How can I set the maximum amount of characters in a UITextField on the iPhone SDK when I load up a UIView?
This question is related to
ios
objective-c
cocoa-touch
uitextfield
The answer is
There is generic solution for setting max length in Swift.
By IBInspectable you can add new Attribute in Xcode Attribute Inspector.
import UIKit
private var maxLengths = [UITextField: Int]()
extension UITextField {
@IBInspectable var maxLength: Int {
get {
guard let length = maxLengths[self]
else {
return Int.max
}
return length
}
set {
maxLengths[self] = newValue
addTarget(
self,
action: Selector("limitLength:"),
forControlEvents: UIControlEvents.EditingChanged
)
}
}
func limitLength(textField: UITextField) {
guard let prospectiveText = textField.text
where prospectiveText.characters.count > maxLength else {
return
}
let selection = selectedTextRange
text = prospectiveText.substringWithRange(
Range<String.Index>(prospectiveText.startIndex ..< prospectiveText.startIndex.advancedBy(maxLength))
)
selectedTextRange = selection
}
}
Swift 4
import UIKit
private var kAssociationKeyMaxLength: Int = 0
extension UITextField {
@IBInspectable var maxLength: Int {
get {
if let length = objc_getAssociatedObject(self, &kAssociationKeyMaxLength) as? Int {
return length
} else {
return Int.max
}
}
set {
objc_setAssociatedObject(self, &kAssociationKeyMaxLength, newValue, .OBJC_ASSOCIATION_RETAIN)
addTarget(self, action: #selector(checkMaxLength), for: .editingChanged)
}
}
@objc func checkMaxLength(textField: UITextField) {
guard let prospectiveText = self.text,
prospectiveText.count > maxLength
else {
return
}
let selection = selectedTextRange
let indexEndOfText = prospectiveText.index(prospectiveText.startIndex, offsetBy: maxLength)
let substring = prospectiveText[..<indexEndOfText]
text = String(substring)
selectedTextRange = selection
}
}
Edit: memory leak issue fixed.
Use below extension to set the maximum character length of a UITextField and UITextView.
Swift 4.0
private var kAssociationKeyMaxLength: Int = 0
private var kAssociationKeyMaxLengthTextView: Int = 0
extension UITextField {
@IBInspectable var maxLength: Int {
get {
if let length = objc_getAssociatedObject(self, &kAssociationKeyMaxLength) as? Int {
return length
} else {
return Int.max
}
}
set {
objc_setAssociatedObject(self, &kAssociationKeyMaxLength, newValue, .OBJC_ASSOCIATION_RETAIN)
addTarget(self, action: #selector(checkMaxLength), for: .editingChanged)
}
}
@objc func checkMaxLength(textField: UITextField) {
guard let prospectiveText = self.text,
prospectiveText.count > maxLength
else {
return
}
let selection = selectedTextRange
let indexEndOfText = prospectiveText.index(prospectiveText.startIndex, offsetBy: maxLength)
let substring = prospectiveText[..<indexEndOfText]
text = String(substring)
selectedTextRange = selection
}
}
UITextView
extension UITextView:UITextViewDelegate {
@IBInspectable var maxLength: Int {
get {
if let length = objc_getAssociatedObject(self, &kAssociationKeyMaxLengthTextView) as? Int {
return length
} else {
return Int.max
}
}
set {
self.delegate = self
objc_setAssociatedObject(self, &kAssociationKeyMaxLengthTextView, newValue, .OBJC_ASSOCIATION_RETAIN)
}
}
public func textViewDidChange(_ textView: UITextView) {
checkMaxLength(textField: self)
}
@objc func checkMaxLength(textField: UITextView) {
guard let prospectiveText = self.text,
prospectiveText.count > maxLength
else {
return
}
let selection = selectedTextRange
let indexEndOfText = prospectiveText.index(prospectiveText.startIndex, offsetBy: maxLength)
let substring = prospectiveText[..<indexEndOfText]
text = String(substring)
selectedTextRange = selection
}
}
You can set limit below.
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
if (textField.text.length >= 50) {
return NO;
}
return YES;
}
we can set the range of textfield like this..
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
int setrange = 20;
return !([textField.text length]>setrange && [string length] > range.length);
}
Thank you august! (Post)
This is the code that I ended up with which works:
#define MAX_LENGTH 20
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if (textField.text.length >= MAX_LENGTH && range.length == 0)
{
return NO; // return NO to not change text
}
else
{return YES;}
}
I want to add to the answer given by @sickp.
There is an issue in his Swift code that occurs with any multibyte text (e.g. emojis). NSRange and String in Swift are not compatible, so it's frustrating that the delegate class combines them. The trick is simply to convert the String objects to NSString The correct solution, based on what @sickp wrote, is actually this:
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let currentText = (textField.text as NSString?) ?? NSString()
let currentCharacterCount = currentText.length
if range.length + range.location > currentCharacterCount {
return false
}
let newLength = currentText.replacingCharacters(in: range, with: string).characters.count
return newLength <= 25
}
Swift 4.2+
By implementing UITextFieldDelegate method
ViewController:
class MyViewController: UIViewController { let MAX_LENGTH = 256 @IBOutlet weak var myTextField: UITextField! override viewDidLoad() { self.myTextField.delegate = self } }Delegate:
extension MyViewController: UITextFieldDelegate { func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool { let userText = textView.text ?? "" var newText = "" if range.length > 0 { let txt = NSString(string: userText) if txt.length > 0 { newText = txt.replacingCharacters(in: range, with: text) } } else { newText = userText + text } return newText.count <= MAX_LENGTH } }
Use this code here RESTRICTED_LENGTH is length you want to restrict for textfield.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if (textField == nameTF) {
int limit = RESTRICTED_LENGTH - 1;
return !([textField.text length]>limit && [string length] > range.length);
}
else
{
return YES;
}
return NO;
}
What about this simple approach. Its working fine for me.
extension UITextField {
func charactersLimit(to:Int) {
if (self.text!.count > to) {
self.deleteBackward()
}
}
}
Then:
someTextField.charactersLimit(to:16)
Swift 3 version //***** This will NOT work with Swift 2.x! *****//
First create a new Swift file : TextFieldMaxLength.swift, and then add the code below:
import UIKit
private var maxLengths = [UITextField: Int]()
extension UITextField {
@IBInspectable var maxLength: Int {
get {
guard let length = maxLengths[self]
else {
return Int.max
}
return length
}
set {
maxLengths[self] = newValue
addTarget(
self,
action: #selector(limitLength),
for: UIControlEvents.editingChanged
)
}
}
func limitLength(textField: UITextField) {
guard let prospectiveText = textField.text,
prospectiveText.characters.count > maxLength
else {
return
}
let selection = selectedTextRange
let maxCharIndex = prospectiveText.index(prospectiveText.startIndex, offsetBy: maxLength)
text = prospectiveText.substring(to: maxCharIndex)
selectedTextRange = selection
}
}
and then you will see in Storyboard a new field (Max Length) when you select any TextField
if you still have more questions check out this link: http://www.globalnerdy.com/2016/05/18/ios-programming-trick-how-to-use-xcode-to-set-a-text-fields-maximum-length-visual-studio-style/
for Swift 3.1 or later
firstly add protocol UITextFieldDelegate
like:-
class PinCodeViewController: UIViewController, UITextFieldDelegate {
.....
.....
.....
}
after that create your UITextField and set delegate
Complete Exp: -
import UIKit
class PinCodeViewController: UIViewController, UITextFieldDelegate {
let pinCodetextField: UITextField = {
let tf = UITextField()
tf.placeholder = "please enter your pincode"
tf.font = UIFont.systemFont(ofSize: 15)
tf.borderStyle = UITextBorderStyle.roundedRect
tf.autocorrectionType = UITextAutocorrectionType.no
tf.keyboardType = UIKeyboardType.numberPad
tf.clearButtonMode = UITextFieldViewMode.whileEditing;
tf.contentVerticalAlignment = UIControlContentVerticalAlignment.center
return tf
}()
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(pinCodetextField)
//----- setup your textfield anchor or position where you want to show it-----
// after that
pinCodetextField.delegate = self // setting the delegate
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
return !(textField.text?.characters.count == 6 && string != "")
} // this is return the maximum characters in textfield
}
For Swift 2.1+
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
if (range.length + range.location > textField.text!.characters.count )
{
return false;
}
let newLength = textField.text!.characters.count + string.characters.count - range.length
return newLength <= 25
}
Hope it helps
You can also do this using NotificationCenter in Swift 4
NotificationCenter.default.addObserver(self, selector: #selector(self.handleTextChange(recognizer:)), name: NSNotification.Name.UITextFieldTextDidChange, object: yourTextField)
@objc func handleTextChange(recognizer: NSNotification) {
//max length is 50 charater max
let textField = recognizer.object as! UITextField
if((textField.text?.count)! > 50) {
let newString: String? = (textField.text as NSString?)?.substring(to: 50)
textField.text = newString
}
}
Often you have multiple input fields with a different length.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
int allowedLength;
switch(textField.tag) {
case 1:
allowedLength = MAXLENGTHNAME; // triggered for input fields with tag = 1
break;
case 2:
allowedLength = MAXLENGTHADDRESS; // triggered for input fields with tag = 2
break;
default:
allowedLength = MAXLENGTHDEFAULT; // length default when no tag (=0) value =255
break;
}
if (textField.text.length >= allowedLength && range.length == 0) {
return NO; // Change not allowed
} else {
return YES; // Change allowed
}
}
If your purpose of limiting text count is to ensure that text will fit into a UILabel elsewhere, I'd avoid using character count. It breaks down with some emoji (trying to truncate a double size emoji will likely crash your app). It's also an issue with some languages like Japanese and Chinese, which have a two-step input process where a simple count just won't work.
I built out a UITextField drop-in subclass (MPC_CharacterLimitedTextField on github). You feed it the expected output label width and it will handle all languages, emoji, and pasting issues. It will harvest only as many full characters that will fit into the label, regardless of the character count. There's a demo in the project so you can test it to see if it's what you need. Hope it will help anybody who was having the same problems with output length that I was.
swift 3.0
This code is working fine when you are paste string more than your character limits.
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
let str = (textView.text + text)
if str.characters.count <= 10 {
return true
}
textView.text = str.substring(to: str.index(str.startIndex, offsetBy: 10))
return false
}
Thanks for your votes. :)
Slightly beyond answering the original question, and expanding on Frouo's answer, here are extensions to trim a String of whitespace and to a max length, and to utilize those String extensions to trim a UITextField to a max length:
// In String_Extensions.swift
extension String {
func trimmedString() -> String {
var trimmedString = self.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
let components = trimmedString.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).filter { count($0) > 0 }
return " ".join(components)
}
func trimmedStringToMaxLength(maxLength: Int) -> String {
return trimmedString().substringToIndex(advance(startIndex, min(count(self), maxLength))).trimmedString()
}
}
// In UITextField_Extensions.swift
private var maxLengthDictionary = [UITextField : Int]()
private var textFieldMaxLength = 20
extension UITextField {
@IBInspectable var maxLength: Int {
get {
if let maxLength = maxLengthDictionary[self] {
return maxLength
} else {
return textFieldMaxLength
}
}
set {
maxLengthDictionary[self] = newValue < textFieldMaxLength + 1 ? newValue : textFieldMaxLength
}
}
func trimAndLimitToMaxLength() {
text = text.trimmedStringToMaxLength(maxLength)
}
}
let someTextField = UITextField()
let someString = " This is a string that is longer than allowable for a text field. "
someTextField.text = someString
someTextField.trimAndLimitToMaxLength()
println(someTextField.text) // Prints "This is a string tha"
let anotherTextField = UITextField()
anotherTextField.maxLength = 5
anotherTextField.text = someString
anotherTextField.trimAndLimitToMaxLength()
println(anotherTextField.text) // Prints "This"
trimAndLimitToMaxLength() could be used in UITextFieldDelegate's textFieldDidEndEditing(_:) so that a user could enter or paste in a longer than acceptable string and then shorten it vs. just cutting off the input at the max length. In doing this, I would also set attributed text styles to indicate any portion of the text that goes beyond the acceptable length (e.g., [NSBackgroundColorAttributeName : UIColor.redColor(), NSForegroundColorAttributeName : UIColor.whiteColor(), NSStrikethroughStyleAttributeName : NSNumber(int: 1)]
Other answers do not handle the case where user can paste a long string from clipboard. If I paste a long string it should just be truncated but shown. Use this in your delegate:
static const NSUInteger maxNoOfCharacters = 5;
-(IBAction)textdidChange:(UITextField * )textField
{
NSString * text = textField.text;
if(text.length > maxNoOfCharacters)
{
text = [text substringWithRange:NSMakeRange(0, maxNoOfCharacters)];
textField.text = text;
}
// use 'text'
}
I give a supplementary answer based on @Frouo. I think his answer is the most beautiful way. Becuase it's a common control we can reuse.
private var kAssociationKeyMaxLength: Int = 0
extension UITextField {
@IBInspectable var maxLength: Int {
get {
if let length = objc_getAssociatedObject(self, &kAssociationKeyMaxLength) as? Int {
return length
} else {
return Int.max
}
}
set {
objc_setAssociatedObject(self, &kAssociationKeyMaxLength, newValue, .OBJC_ASSOCIATION_RETAIN)
self.addTarget(self, action: #selector(checkMaxLength), for: .editingChanged)
}
}
func checkMaxLength(textField: UITextField) {
guard !self.isInputMethod(), let prospectiveText = self.text,
prospectiveText.count > maxLength
else {
return
}
let selection = selectedTextRange
let maxCharIndex = prospectiveText.index(prospectiveText.startIndex, offsetBy: maxLength)
text = prospectiveText.substring(to: maxCharIndex)
selectedTextRange = selection
}
//The method is used to cancel the check when use Chinese Pinyin input method.
//Becuase the alphabet also appears in the textfield when inputting, we should cancel the check.
func isInputMethod() -> Bool {
if let positionRange = self.markedTextRange {
if let _ = self.position(from: positionRange.start, offset: 0) {
return true
}
}
return false
}
}
You can't do this directly - UITextField has no maxLength attribute, but you can set the UITextField's delegate, then use:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
The best way would be to set up a notification on the text changing. In your -awakeFromNib of your view controller method you'll want:
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(limitTextField:) name:@"UITextFieldTextDidChangeNotification" object:myTextField];
Then in the same class add:
- (void)limitTextField:(NSNotification *)note {
int limit = 20;
if ([[myTextField stringValue] length] > limit) {
[myTextField setStringValue:[[myTextField stringValue] substringToIndex:limit]];
}
}
Then link up the outlet myTextField to your UITextField and it will not let you add any more characters after you hit the limit. Be sure to add this to your dealloc method:
[[NSNotificationCenter defaultCenter] removeObserver:self name:@"UITextFieldTextDidChangeNotification" object:myTextField];
I found this quick and simple
- (IBAction)backgroundClick:(id)sender {
if (mytext.length <= 7) {
[mytext resignFirstResponder];
} else {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Too Big"
message:@"Please Shorten Name"
delegate:nil
cancelButtonTitle:@"Cancel"
otherButtonTitles:nil];
[alert show];
[alert release];
}
}
The following code is similar to sickp's answer but handles correctly copy-paste operations. If you try to paste a text that is longer than the limit, the following code will truncate the text to fit the limit instead of refusing the paste operation completely.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
static const NSUInteger limit = 70; // we limit to 70 characters
NSUInteger allowedLength = limit - [textField.text length] + range.length;
if (string.length > allowedLength) {
if (string.length > 1) {
// get at least the part of the new string that fits
NSString *limitedString = [string substringToIndex:allowedLength];
NSMutableString *newString = [textField.text mutableCopy];
[newString replaceCharactersInRange:range withString:limitedString];
textField.text = newString;
}
return NO;
} else {
return YES;
}
}
(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
if ([txt_name.text length]>100)
{
return NO;
}
return YES;
}
Other answers do not handle the case where user can paste a long string from clipboard. If I paste a long string it should just be truncated but shown. Use this in your delegate:
static const NSUInteger maxNoOfCharacters = 5;
-(IBAction)textdidChange:(UITextField * )textField
{
NSString * text = textField.text;
if(text.length > maxNoOfCharacters)
{
text = [text substringWithRange:NSMakeRange(0, maxNoOfCharacters)];
textField.text = text;
}
// use 'text'
}
For Swift 2.1+
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
if (range.length + range.location > textField.text!.characters.count )
{
return false;
}
let newLength = textField.text!.characters.count + string.characters.count - range.length
return newLength <= 25
}
Hope it helps
You can't do this directly - UITextField has no maxLength attribute, but you can set the UITextField's delegate, then use:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
now how many characters u want just give values
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSUInteger newLength = [textField.text length] + [string length] - range.length;
return (newLength > 25) ? NO : YES;
}
Thank you august! (Post)
This is the code that I ended up with which works:
#define MAX_LENGTH 20
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if (textField.text.length >= MAX_LENGTH && range.length == 0)
{
return NO; // return NO to not change text
}
else
{return YES;}
}
For Xamarin:
YourTextField.ShouldChangeCharacters =
delegate(UITextField textField, NSRange range, string replacementString)
{
return (range.Location + replacementString.Length) <= 4; // MaxLength == 4
};
I did this in Swift for an 8 character limit when using a number pad.
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
return !(textField.text?.characters.count == MAX_LENGTH && string != "")
}
I had to test for string != "" to allow the delete button to work on the number pad, otherwise it wouldn't allow deleting characters in the text field after it reached its max.
swift 3.0
This code is working fine when you are paste string more than your character limits.
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
let str = (textView.text + text)
if str.characters.count <= 10 {
return true
}
textView.text = str.substring(to: str.index(str.startIndex, offsetBy: 10))
return false
}
Thanks for your votes. :)
I have open sourced a UITextField subclass, STATextField, that offers this functionality (and much more) with its maxCharacterLength property.
Got it down to 1 line of code :)
Set your text view's delegate to "self" then add the <UITextViewDelegate> in your .h and the following code in your .m .... you can adjust the number "7" to be whatever you want your MAXIMUM number of characters to be.
-(BOOL)textView:(UITextView *)a shouldChangeTextInRange:(NSRange)b replacementText:(NSString *)c {
return ((a.text.length+c.length<=7)+(c.length<1)+(b.length>=c.length)>0);
}
This code accounts for typing new characters, deleting characters, selecting characters then typing or deleting, selecting characters and cutting, pasting in general, and selecting characters and pasting.
Done!
Alternatively, another cool way to write this code with bit-operations would be
-(BOOL)textView:(UITextView *)a shouldChangeTextInRange:(NSRange)b replacementText:(NSString *)c {
return 0^((a.text.length+c.length<=7)+(c.length<1)+(b.length>=c.length));
}
What about this simple approach. Its working fine for me.
extension UITextField {
func charactersLimit(to:Int) {
if (self.text!.count > to) {
self.deleteBackward()
}
}
}
Then:
someTextField.charactersLimit(to:16)
I have implemented a UITextField Extension to add a maxLength property to it.
It's based on Xcode 6 IBInspectables, so you can set the maxLength limit on the Interface builder.
Here is the implementation:
UITextField+MaxLength.h
#import <UIKit/UIKit.h>
@interface UITextField_MaxLength : UITextField<UITextFieldDelegate>
@property (nonatomic)IBInspectable int textMaxLength;
@end
UITextField+MaxLength.m
#import "UITextField+MaxLength.h"
@interface UITextField_MaxLength()
@property (nonatomic, assign) id <UITextFieldDelegate> superDelegate;
@end
@implementation UITextField_MaxLength
- (BOOL)textField:(UITextField *) textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
//validate the length, only if it's set to a non zero value
if (self.textMaxLength>0) {
if(range.length + range.location > textField.text.length)
return NO;
if (textField.text.length+string.length - range.length>self.textMaxLength) {
return NO;
}
}
//if length validation was passed, query the super class to see if the delegate method is implemented there
if (self.superDelegate && [self.superDelegate respondsToSelector:@selector(textField:shouldChangeCharactersInRange:replacementString:)]) {
return [self.superDelegate textField:textField shouldChangeCharactersInRange:range replacementString:string];
}
else{
//if the super class does not implement the delegate method, simply return YES as the length validation was passed
return YES;
}
}
- (void)setDelegate:(id<UITextFieldDelegate>)delegate {
if (delegate == self)
return;
self.superDelegate = delegate;
[super setDelegate:self];
}
//forward all non overriden delegate methods
- (id)forwardingTargetForSelector:(SEL)aSelector {
if ([self.superDelegate respondsToSelector:aSelector])
return self.superDelegate;
return [super forwardingTargetForSelector:aSelector];
}
- (BOOL)respondsToSelector:(SEL)aSelector {
if ([self.superDelegate respondsToSelector:aSelector])
return YES;
return [super respondsToSelector:aSelector];
}
@end
There is generic solution for setting max length in Swift.
By IBInspectable you can add new Attribute in Xcode Attribute Inspector.
import UIKit
private var maxLengths = [UITextField: Int]()
extension UITextField {
@IBInspectable var maxLength: Int {
get {
guard let length = maxLengths[self]
else {
return Int.max
}
return length
}
set {
maxLengths[self] = newValue
addTarget(
self,
action: Selector("limitLength:"),
forControlEvents: UIControlEvents.EditingChanged
)
}
}
func limitLength(textField: UITextField) {
guard let prospectiveText = textField.text
where prospectiveText.characters.count > maxLength else {
return
}
let selection = selectedTextRange
text = prospectiveText.substringWithRange(
Range<String.Index>(prospectiveText.startIndex ..< prospectiveText.startIndex.advancedBy(maxLength))
)
selectedTextRange = selection
}
}
Often you have multiple input fields with a different length.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
int allowedLength;
switch(textField.tag) {
case 1:
allowedLength = MAXLENGTHNAME; // triggered for input fields with tag = 1
break;
case 2:
allowedLength = MAXLENGTHADDRESS; // triggered for input fields with tag = 2
break;
default:
allowedLength = MAXLENGTHDEFAULT; // length default when no tag (=0) value =255
break;
}
if (textField.text.length >= allowedLength && range.length == 0) {
return NO; // Change not allowed
} else {
return YES; // Change allowed
}
}
Swift 2.0 +
First of all create a class for this process. Lets call it StringValidator.swift.
Then just paste the following code inside it.
import Foundation
extension String {
func containsCharactersIn(matchCharacters: String) -> Bool {
let characterSet = NSCharacterSet(charactersInString: matchCharacters)
return self.rangeOfCharacterFromSet(characterSet) != nil
}
func containsOnlyCharactersIn(matchCharacters: String) -> Bool {
let disallowedCharacterSet = NSCharacterSet(charactersInString: matchCharacters).invertedSet
return self.rangeOfCharacterFromSet(disallowedCharacterSet) == nil
}
func doesNotContainCharactersIn(matchCharacters: String) -> Bool {
let characterSet = NSCharacterSet(charactersInString: matchCharacters)
return self.rangeOfCharacterFromSet(characterSet) == nil
}
func isNumeric() -> Bool
{
let scanner = NSScanner(string: self)
scanner.locale = NSLocale.currentLocale()
return scanner.scanDecimal(nil) && scanner.atEnd
}
}
Now save the class.....
Usage..
Now goto your viewController.swift class and make your textfield's outlets as..
@IBOutlet weak var contactEntryTxtFld: UITextField! //First textfield
@IBOutlet weak var contactEntryTxtFld2: UITextField! //Second textfield
Now goto the textfield's shouldChangeCharactersInRange method and use like the following.
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
if string.characters.count == 0 {
return true
}
let latestText = textField.text ?? ""
let checkAbleText = (latestText as NSString).stringByReplacingCharactersInRange(range, withString: string)
switch textField {
case contactEntryTxtFld:
return checkAbleText.containsOnlyCharactersIn("0123456789") && prospectiveText.characters.count <= 5
case contactEntryTxtFld2:
return checkAbleText.containsOnlyCharactersIn("0123456789") && prospectiveText.characters.count <= 5
default:
return true
}
}
Don't forget to set the delegate protocol/methods of textfields.
Let me explain about this... I am using the simple extension process of string which I wrote inside an another class. Now I am just calling those extension methods from another class where I need them by adding check and maximum value.
Features...
- It will set maximum limit of a particular textfield.
- It will set type of accepted keys for particular textfield.
Types...
containsOnlyCharactersIn //Accepts only Characters.
containsCharactersIn //Accepts combination of characters
doesNotContainsCharactersIn //Will not accept characters
Hope this helped.... Thanks..
This should be enough to solve the problem (replace 4 by the limit u want). Just make sure to add delegate in IB.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
return (newString.length<=4);
}
The best way would be to set up a notification on the text changing. In your -awakeFromNib of your view controller method you'll want:
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(limitTextField:) name:@"UITextFieldTextDidChangeNotification" object:myTextField];
Then in the same class add:
- (void)limitTextField:(NSNotification *)note {
int limit = 20;
if ([[myTextField stringValue] length] > limit) {
[myTextField setStringValue:[[myTextField stringValue] substringToIndex:limit]];
}
}
Then link up the outlet myTextField to your UITextField and it will not let you add any more characters after you hit the limit. Be sure to add this to your dealloc method:
[[NSNotificationCenter defaultCenter] removeObserver:self name:@"UITextFieldTextDidChangeNotification" object:myTextField];
The following code is similar to sickp's answer but handles correctly copy-paste operations. If you try to paste a text that is longer than the limit, the following code will truncate the text to fit the limit instead of refusing the paste operation completely.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
static const NSUInteger limit = 70; // we limit to 70 characters
NSUInteger allowedLength = limit - [textField.text length] + range.length;
if (string.length > allowedLength) {
if (string.length > 1) {
// get at least the part of the new string that fits
NSString *limitedString = [string substringToIndex:allowedLength];
NSMutableString *newString = [textField.text mutableCopy];
[newString replaceCharactersInRange:range withString:limitedString];
textField.text = newString;
}
return NO;
} else {
return YES;
}
}
I did this in Swift for an 8 character limit when using a number pad.
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
return !(textField.text?.characters.count == MAX_LENGTH && string != "")
}
I had to test for string != "" to allow the delete button to work on the number pad, otherwise it wouldn't allow deleting characters in the text field after it reached its max.
for Swift 3.1 or later
firstly add protocol UITextFieldDelegate
like:-
class PinCodeViewController: UIViewController, UITextFieldDelegate {
.....
.....
.....
}
after that create your UITextField and set delegate
Complete Exp: -
import UIKit
class PinCodeViewController: UIViewController, UITextFieldDelegate {
let pinCodetextField: UITextField = {
let tf = UITextField()
tf.placeholder = "please enter your pincode"
tf.font = UIFont.systemFont(ofSize: 15)
tf.borderStyle = UITextBorderStyle.roundedRect
tf.autocorrectionType = UITextAutocorrectionType.no
tf.keyboardType = UIKeyboardType.numberPad
tf.clearButtonMode = UITextFieldViewMode.whileEditing;
tf.contentVerticalAlignment = UIControlContentVerticalAlignment.center
return tf
}()
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(pinCodetextField)
//----- setup your textfield anchor or position where you want to show it-----
// after that
pinCodetextField.delegate = self // setting the delegate
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
return !(textField.text?.characters.count == 6 && string != "")
} // this is return the maximum characters in textfield
}
Swift 4.2 and UITextFieldDelegate method
This works for me and limits the textfield to have a max input of 8 characters. Hopefully NSRange will eventually be changed to Range but for now I am happy to use NSString as creating a Range from NSRange involves dealing with another optional.
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let text = textField.text ?? ""
let nsString = text as NSString
let newText = nsString.replacingCharacters(in: range, with: string)
return newText.count <= 8
}
To make it work with cut & paste of strings of any length, I would suggest changing the function to something like:
#define MAX_LENGTH 20
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSInteger insertDelta = string.length - range.length;
if (textField.text.length + insertDelta > MAX_LENGTH)
{
return NO; // the new string would be longer than MAX_LENGTH
}
else {
return YES;
}
}
For Xamarin:
YourTextField.ShouldChangeCharacters =
delegate(UITextField textField, NSRange range, string replacementString)
{
return (range.Location + replacementString.Length) <= 4; // MaxLength == 4
};
I simulate the actual string replacement that's about to happen to calculate that future string's length:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
if([newString length] > maxLength)
return NO;
return YES;
}
The Problem with some of the answer given above is, For example I have a text field and I have to set a limit of 15 characters input, then it stops after entering 15th Character. but they Don't allow to delete. That is the delete button also don't work. As I was facing the same problem. Came out with the solution , Given Below. Works Perfect for Me
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if(textField.tag==6)
{
if ([textField.text length]<=30)
{
return YES;
}
else if([@"" isEqualToString:string])
{
textField.text=[textField.text substringToIndex:30 ];
}
return NO;
}
else
{
return YES;
}
}
I am having a text field, whose tag I have set "6" and I have restricted the max char limit = 30 ; works fine in every case
Swift 4
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
guard let text = textField.text else { return true }
let newLength = text.count + string.count - range.length
return newLength <= 10
}
Use below extension to set the maximum character length of a UITextField and UITextView.
Swift 4.0
private var kAssociationKeyMaxLength: Int = 0
private var kAssociationKeyMaxLengthTextView: Int = 0
extension UITextField {
@IBInspectable var maxLength: Int {
get {
if let length = objc_getAssociatedObject(self, &kAssociationKeyMaxLength) as? Int {
return length
} else {
return Int.max
}
}
set {
objc_setAssociatedObject(self, &kAssociationKeyMaxLength, newValue, .OBJC_ASSOCIATION_RETAIN)
addTarget(self, action: #selector(checkMaxLength), for: .editingChanged)
}
}
@objc func checkMaxLength(textField: UITextField) {
guard let prospectiveText = self.text,
prospectiveText.count > maxLength
else {
return
}
let selection = selectedTextRange
let indexEndOfText = prospectiveText.index(prospectiveText.startIndex, offsetBy: maxLength)
let substring = prospectiveText[..<indexEndOfText]
text = String(substring)
selectedTextRange = selection
}
}
UITextView
extension UITextView:UITextViewDelegate {
@IBInspectable var maxLength: Int {
get {
if let length = objc_getAssociatedObject(self, &kAssociationKeyMaxLengthTextView) as? Int {
return length
} else {
return Int.max
}
}
set {
self.delegate = self
objc_setAssociatedObject(self, &kAssociationKeyMaxLengthTextView, newValue, .OBJC_ASSOCIATION_RETAIN)
}
}
public func textViewDidChange(_ textView: UITextView) {
checkMaxLength(textField: self)
}
@objc func checkMaxLength(textField: UITextView) {
guard let prospectiveText = self.text,
prospectiveText.count > maxLength
else {
return
}
let selection = selectedTextRange
let indexEndOfText = prospectiveText.index(prospectiveText.startIndex, offsetBy: maxLength)
let substring = prospectiveText[..<indexEndOfText]
text = String(substring)
selectedTextRange = selection
}
}
You can set limit below.
I found this quick and simple
- (IBAction)backgroundClick:(id)sender {
if (mytext.length <= 7) {
[mytext resignFirstResponder];
} else {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Too Big"
message:@"Please Shorten Name"
delegate:nil
cancelButtonTitle:@"Cancel"
otherButtonTitles:nil];
[alert show];
[alert release];
}
}
You can also do this using NotificationCenter in Swift 4
NotificationCenter.default.addObserver(self, selector: #selector(self.handleTextChange(recognizer:)), name: NSNotification.Name.UITextFieldTextDidChange, object: yourTextField)
@objc func handleTextChange(recognizer: NSNotification) {
//max length is 50 charater max
let textField = recognizer.object as! UITextField
if((textField.text?.count)! > 50) {
let newString: String? = (textField.text as NSString?)?.substring(to: 50)
textField.text = newString
}
}
I have implemented a UITextField Extension to add a maxLength property to it.
It's based on Xcode 6 IBInspectables, so you can set the maxLength limit on the Interface builder.
Here is the implementation:
UITextField+MaxLength.h
#import <UIKit/UIKit.h>
@interface UITextField_MaxLength : UITextField<UITextFieldDelegate>
@property (nonatomic)IBInspectable int textMaxLength;
@end
UITextField+MaxLength.m
#import "UITextField+MaxLength.h"
@interface UITextField_MaxLength()
@property (nonatomic, assign) id <UITextFieldDelegate> superDelegate;
@end
@implementation UITextField_MaxLength
- (BOOL)textField:(UITextField *) textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
//validate the length, only if it's set to a non zero value
if (self.textMaxLength>0) {
if(range.length + range.location > textField.text.length)
return NO;
if (textField.text.length+string.length - range.length>self.textMaxLength) {
return NO;
}
}
//if length validation was passed, query the super class to see if the delegate method is implemented there
if (self.superDelegate && [self.superDelegate respondsToSelector:@selector(textField:shouldChangeCharactersInRange:replacementString:)]) {
return [self.superDelegate textField:textField shouldChangeCharactersInRange:range replacementString:string];
}
else{
//if the super class does not implement the delegate method, simply return YES as the length validation was passed
return YES;
}
}
- (void)setDelegate:(id<UITextFieldDelegate>)delegate {
if (delegate == self)
return;
self.superDelegate = delegate;
[super setDelegate:self];
}
//forward all non overriden delegate methods
- (id)forwardingTargetForSelector:(SEL)aSelector {
if ([self.superDelegate respondsToSelector:aSelector])
return self.superDelegate;
return [super forwardingTargetForSelector:aSelector];
}
- (BOOL)respondsToSelector:(SEL)aSelector {
if ([self.superDelegate respondsToSelector:aSelector])
return YES;
return [super respondsToSelector:aSelector];
}
@end
(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
if ([txt_name.text length]>100)
{
return NO;
}
return YES;
}
The Problem with some of the answer given above is, For example I have a text field and I have to set a limit of 15 characters input, then it stops after entering 15th Character. but they Don't allow to delete. That is the delete button also don't work. As I was facing the same problem. Came out with the solution , Given Below. Works Perfect for Me
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if(textField.tag==6)
{
if ([textField.text length]<=30)
{
return YES;
}
else if([@"" isEqualToString:string])
{
textField.text=[textField.text substringToIndex:30 ];
}
return NO;
}
else
{
return YES;
}
}
I am having a text field, whose tag I have set "6" and I have restricted the max char limit = 30 ; works fine in every case
The best way would be to set up a notification on the text changing. In your -awakeFromNib of your view controller method you'll want:
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(limitTextField:) name:@"UITextFieldTextDidChangeNotification" object:myTextField];
Then in the same class add:
- (void)limitTextField:(NSNotification *)note {
int limit = 20;
if ([[myTextField stringValue] length] > limit) {
[myTextField setStringValue:[[myTextField stringValue] substringToIndex:limit]];
}
}
Then link up the outlet myTextField to your UITextField and it will not let you add any more characters after you hit the limit. Be sure to add this to your dealloc method:
[[NSNotificationCenter defaultCenter] removeObserver:self name:@"UITextFieldTextDidChangeNotification" object:myTextField];
This is the correct way to handle max length on UITextField, it allows the return key to exit the resign the textfield as first responder and lets the user backspace when they reach the limit
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
int MAX_LENGHT = 5;
if([string isEqualToString:@"\n"])
{
[textField resignFirstResponder];
return FALSE;
}
else if(textField.text.length > MAX_LENGHT-1)
{
if([string isEqualToString:@""] && range.length == 1)
{
return TRUE;
}
else
{
return FALSE;
}
}
else
{
return TRUE;
}
}
I simulate the actual string replacement that's about to happen to calculate that future string's length:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
if([newString length] > maxLength)
return NO;
return YES;
}
This is the correct way to handle max length on UITextField, it allows the return key to exit the resign the textfield as first responder and lets the user backspace when they reach the limit
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
int MAX_LENGHT = 5;
if([string isEqualToString:@"\n"])
{
[textField resignFirstResponder];
return FALSE;
}
else if(textField.text.length > MAX_LENGHT-1)
{
if([string isEqualToString:@""] && range.length == 1)
{
return TRUE;
}
else
{
return FALSE;
}
}
else
{
return TRUE;
}
}
Thank you august! (Post)
This is the code that I ended up with which works:
#define MAX_LENGTH 20
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if (textField.text.length >= MAX_LENGTH && range.length == 0)
{
return NO; // return NO to not change text
}
else
{return YES;}
}
This limits the number of characters, but also make sure that you can paste in the field until the maximum limit.
- (void)textViewDidChange:(UITextView *)textView
{
NSString* str = [textView text];
str = [str substringToIndex:MIN(1000,[str length])];
[textView setText:str];
if([str length]==1000) {
// show some label that you've reached the limit of 1000 characters
}
}
To make it work with cut & paste of strings of any length, I would suggest changing the function to something like:
#define MAX_LENGTH 20
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSInteger insertDelta = string.length - range.length;
if (textField.text.length + insertDelta > MAX_LENGTH)
{
return NO; // the new string would be longer than MAX_LENGTH
}
else {
return YES;
}
}
I created this UITextFieldLimit subclass:
- Multiple textfields supported
- Set the text length limit
- Paste prevention
- Displays a label of left characters inside the textfield, get hidden when you stop editing.
- Shake animation when no characters left.
Grab the UITextFieldLimit.h and UITextFieldLimit.m from this GitHub repository:
https://github.com/JonathanGurebo/UITextFieldLimit
and begin to test!
Mark your storyboard-created UITextField and link it to my subclass using the Identity Inspector:
Then you can link it to an IBOutlet and set the limit(default is 10).
Your ViewController.h file should contain: (if you wan't to modify the setting, like the limit)
#import "UITextFieldLimit.h"
/.../
@property (weak, nonatomic) IBOutlet UITextFieldLimit *textFieldLimit; // <--Your IBOutlet
Your ViewController.m file should @synthesize textFieldLimit.
Set the text length limit in your ViewController.m file:
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[textFieldLimit setLimit:25];// <-- and you won't be able to put more than 25 characters in the TextField.
}
Hope the class helps you. Good luck!
If your purpose of limiting text count is to ensure that text will fit into a UILabel elsewhere, I'd avoid using character count. It breaks down with some emoji (trying to truncate a double size emoji will likely crash your app). It's also an issue with some languages like Japanese and Chinese, which have a two-step input process where a simple count just won't work.
I built out a UITextField drop-in subclass (MPC_CharacterLimitedTextField on github). You feed it the expected output label width and it will handle all languages, emoji, and pasting issues. It will harvest only as many full characters that will fit into the label, regardless of the character count. There's a demo in the project so you can test it to see if it's what you need. Hope it will help anybody who was having the same problems with output length that I was.
Got it down to 1 line of code :)
Set your text view's delegate to "self" then add the <UITextViewDelegate> in your .h and the following code in your .m .... you can adjust the number "7" to be whatever you want your MAXIMUM number of characters to be.
-(BOOL)textView:(UITextView *)a shouldChangeTextInRange:(NSRange)b replacementText:(NSString *)c {
return ((a.text.length+c.length<=7)+(c.length<1)+(b.length>=c.length)>0);
}
This code accounts for typing new characters, deleting characters, selecting characters then typing or deleting, selecting characters and cutting, pasting in general, and selecting characters and pasting.
Done!
Alternatively, another cool way to write this code with bit-operations would be
-(BOOL)textView:(UITextView *)a shouldChangeTextInRange:(NSRange)b replacementText:(NSString *)c {
return 0^((a.text.length+c.length<=7)+(c.length<1)+(b.length>=c.length));
}
Slightly beyond answering the original question, and expanding on Frouo's answer, here are extensions to trim a String of whitespace and to a max length, and to utilize those String extensions to trim a UITextField to a max length:
// In String_Extensions.swift
extension String {
func trimmedString() -> String {
var trimmedString = self.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
let components = trimmedString.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).filter { count($0) > 0 }
return " ".join(components)
}
func trimmedStringToMaxLength(maxLength: Int) -> String {
return trimmedString().substringToIndex(advance(startIndex, min(count(self), maxLength))).trimmedString()
}
}
// In UITextField_Extensions.swift
private var maxLengthDictionary = [UITextField : Int]()
private var textFieldMaxLength = 20
extension UITextField {
@IBInspectable var maxLength: Int {
get {
if let maxLength = maxLengthDictionary[self] {
return maxLength
} else {
return textFieldMaxLength
}
}
set {
maxLengthDictionary[self] = newValue < textFieldMaxLength + 1 ? newValue : textFieldMaxLength
}
}
func trimAndLimitToMaxLength() {
text = text.trimmedStringToMaxLength(maxLength)
}
}
let someTextField = UITextField()
let someString = " This is a string that is longer than allowable for a text field. "
someTextField.text = someString
someTextField.trimAndLimitToMaxLength()
println(someTextField.text) // Prints "This is a string tha"
let anotherTextField = UITextField()
anotherTextField.maxLength = 5
anotherTextField.text = someString
anotherTextField.trimAndLimitToMaxLength()
println(anotherTextField.text) // Prints "This"
trimAndLimitToMaxLength() could be used in UITextFieldDelegate's textFieldDidEndEditing(_:) so that a user could enter or paste in a longer than acceptable string and then shorten it vs. just cutting off the input at the max length. In doing this, I would also set attributed text styles to indicate any portion of the text that goes beyond the acceptable length (e.g., [NSBackgroundColorAttributeName : UIColor.redColor(), NSForegroundColorAttributeName : UIColor.whiteColor(), NSStrikethroughStyleAttributeName : NSNumber(int: 1)]
I have open sourced a UITextField subclass, STATextField, that offers this functionality (and much more) with its maxCharacterLength property.
now how many characters u want just give values
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSUInteger newLength = [textField.text length] + [string length] - range.length;
return (newLength > 25) ? NO : YES;
}
You can't do this directly - UITextField has no maxLength attribute, but you can set the UITextField's delegate, then use:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
Swift 4.2 and UITextFieldDelegate method
This works for me and limits the textfield to have a max input of 8 characters. Hopefully NSRange will eventually be changed to Range but for now I am happy to use NSString as creating a Range from NSRange involves dealing with another optional.
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let text = textField.text ?? ""
let nsString = text as NSString
let newText = nsString.replacingCharacters(in: range, with: string)
return newText.count <= 8
}
Use this code here RESTRICTED_LENGTH is length you want to restrict for textfield.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if (textField == nameTF) {
int limit = RESTRICTED_LENGTH - 1;
return !([textField.text length]>limit && [string length] > range.length);
}
else
{
return YES;
}
return NO;
}
The best way would be to set up a notification on the text changing. In your -awakeFromNib of your view controller method you'll want:
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(limitTextField:) name:@"UITextFieldTextDidChangeNotification" object:myTextField];
Then in the same class add:
- (void)limitTextField:(NSNotification *)note {
int limit = 20;
if ([[myTextField stringValue] length] > limit) {
[myTextField setStringValue:[[myTextField stringValue] substringToIndex:limit]];
}
}
Then link up the outlet myTextField to your UITextField and it will not let you add any more characters after you hit the limit. Be sure to add this to your dealloc method:
[[NSNotificationCenter defaultCenter] removeObserver:self name:@"UITextFieldTextDidChangeNotification" object:myTextField];
Using Interface builder you can link and get the event for "Editing changed" in any of your function. Now there you can put check for the length
- (IBAction)onValueChange:(id)sender
{
NSString *text = nil;
int MAX_LENGTH = 20;
switch ([sender tag] )
{
case 1:
{
text = myEditField.text;
if (MAX_LENGTH < [text length]) {
myEditField.text = [text substringToIndex:MAX_LENGTH];
}
}
break;
default:
break;
}
}
Swift 3 version //***** This will NOT work with Swift 2.x! *****//
First create a new Swift file : TextFieldMaxLength.swift, and then add the code below:
import UIKit
private var maxLengths = [UITextField: Int]()
extension UITextField {
@IBInspectable var maxLength: Int {
get {
guard let length = maxLengths[self]
else {
return Int.max
}
return length
}
set {
maxLengths[self] = newValue
addTarget(
self,
action: #selector(limitLength),
for: UIControlEvents.editingChanged
)
}
}
func limitLength(textField: UITextField) {
guard let prospectiveText = textField.text,
prospectiveText.characters.count > maxLength
else {
return
}
let selection = selectedTextRange
let maxCharIndex = prospectiveText.index(prospectiveText.startIndex, offsetBy: maxLength)
text = prospectiveText.substring(to: maxCharIndex)
selectedTextRange = selection
}
}
and then you will see in Storyboard a new field (Max Length) when you select any TextField
if you still have more questions check out this link: http://www.globalnerdy.com/2016/05/18/ios-programming-trick-how-to-use-xcode-to-set-a-text-fields-maximum-length-visual-studio-style/
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
if (textField.text.length >= 50) {
return NO;
}
return YES;
}
To complete August answer, an possible implementation of the proposed function (see UITextField's delegate).
I did not test domness code, but mine do not get stuck if the user reached the limit, and it is compatible with a new string that comes replace a smaller or equal one.
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
//limit the size :
int limit = 20;
return !([textField.text length]>limit && [string length] > range.length);
}
Swift 4.2+
By implementing UITextFieldDelegate method
ViewController:
class MyViewController: UIViewController { let MAX_LENGTH = 256 @IBOutlet weak var myTextField: UITextField! override viewDidLoad() { self.myTextField.delegate = self } }Delegate:
extension MyViewController: UITextFieldDelegate { func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool { let userText = textView.text ?? "" var newText = "" if range.length > 0 { let txt = NSString(string: userText) if txt.length > 0 { newText = txt.replacingCharacters(in: range, with: text) } } else { newText = userText + text } return newText.count <= MAX_LENGTH } }
I created this UITextFieldLimit subclass:
- Multiple textfields supported
- Set the text length limit
- Paste prevention
- Displays a label of left characters inside the textfield, get hidden when you stop editing.
- Shake animation when no characters left.
Grab the UITextFieldLimit.h and UITextFieldLimit.m from this GitHub repository:
https://github.com/JonathanGurebo/UITextFieldLimit
and begin to test!
Mark your storyboard-created UITextField and link it to my subclass using the Identity Inspector:
Then you can link it to an IBOutlet and set the limit(default is 10).
Your ViewController.h file should contain: (if you wan't to modify the setting, like the limit)
#import "UITextFieldLimit.h"
/.../
@property (weak, nonatomic) IBOutlet UITextFieldLimit *textFieldLimit; // <--Your IBOutlet
Your ViewController.m file should @synthesize textFieldLimit.
Set the text length limit in your ViewController.m file:
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[textFieldLimit setLimit:25];// <-- and you won't be able to put more than 25 characters in the TextField.
}
Hope the class helps you. Good luck!
Thank you august! (Post)
This is the code that I ended up with which works:
#define MAX_LENGTH 20
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if (textField.text.length >= MAX_LENGTH && range.length == 0)
{
return NO; // return NO to not change text
}
else
{return YES;}
}
I give a supplementary answer based on @Frouo. I think his answer is the most beautiful way. Becuase it's a common control we can reuse.
private var kAssociationKeyMaxLength: Int = 0
extension UITextField {
@IBInspectable var maxLength: Int {
get {
if let length = objc_getAssociatedObject(self, &kAssociationKeyMaxLength) as? Int {
return length
} else {
return Int.max
}
}
set {
objc_setAssociatedObject(self, &kAssociationKeyMaxLength, newValue, .OBJC_ASSOCIATION_RETAIN)
self.addTarget(self, action: #selector(checkMaxLength), for: .editingChanged)
}
}
func checkMaxLength(textField: UITextField) {
guard !self.isInputMethod(), let prospectiveText = self.text,
prospectiveText.count > maxLength
else {
return
}
let selection = selectedTextRange
let maxCharIndex = prospectiveText.index(prospectiveText.startIndex, offsetBy: maxLength)
text = prospectiveText.substring(to: maxCharIndex)
selectedTextRange = selection
}
//The method is used to cancel the check when use Chinese Pinyin input method.
//Becuase the alphabet also appears in the textfield when inputting, we should cancel the check.
func isInputMethod() -> Bool {
if let positionRange = self.markedTextRange {
if let _ = self.position(from: positionRange.start, offset: 0) {
return true
}
}
return false
}
}
I want to add to the answer given by @sickp.
There is an issue in his Swift code that occurs with any multibyte text (e.g. emojis). NSRange and String in Swift are not compatible, so it's frustrating that the delegate class combines them. The trick is simply to convert the String objects to NSString The correct solution, based on what @sickp wrote, is actually this:
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let currentText = (textField.text as NSString?) ?? NSString()
let currentCharacterCount = currentText.length
if range.length + range.location > currentCharacterCount {
return false
}
let newLength = currentText.replacingCharacters(in: range, with: string).characters.count
return newLength <= 25
}
Using Interface builder you can link and get the event for "Editing changed" in any of your function. Now there you can put check for the length
- (IBAction)onValueChange:(id)sender
{
NSString *text = nil;
int MAX_LENGTH = 20;
switch ([sender tag] )
{
case 1:
{
text = myEditField.text;
if (MAX_LENGTH < [text length]) {
myEditField.text = [text substringToIndex:MAX_LENGTH];
}
}
break;
default:
break;
}
}
Swift 4
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
guard let text = textField.text else { return true }
let newLength = text.count + string.count - range.length
return newLength <= 10
}
This should be enough to solve the problem (replace 4 by the limit u want). Just make sure to add delegate in IB.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
return (newString.length<=4);
}
Swift 4
import UIKit
private var kAssociationKeyMaxLength: Int = 0
extension UITextField {
@IBInspectable var maxLength: Int {
get {
if let length = objc_getAssociatedObject(self, &kAssociationKeyMaxLength) as? Int {
return length
} else {
return Int.max
}
}
set {
objc_setAssociatedObject(self, &kAssociationKeyMaxLength, newValue, .OBJC_ASSOCIATION_RETAIN)
addTarget(self, action: #selector(checkMaxLength), for: .editingChanged)
}
}
@objc func checkMaxLength(textField: UITextField) {
guard let prospectiveText = self.text,
prospectiveText.count > maxLength
else {
return
}
let selection = selectedTextRange
let indexEndOfText = prospectiveText.index(prospectiveText.startIndex, offsetBy: maxLength)
let substring = prospectiveText[..<indexEndOfText]
text = String(substring)
selectedTextRange = selection
}
}
Edit: memory leak issue fixed.
This limits the number of characters, but also make sure that you can paste in the field until the maximum limit.
- (void)textViewDidChange:(UITextView *)textView
{
NSString* str = [textView text];
str = [str substringToIndex:MIN(1000,[str length])];
[textView setText:str];
if([str length]==1000) {
// show some label that you've reached the limit of 1000 characters
}
}
Swift 2.0 +
First of all create a class for this process. Lets call it StringValidator.swift.
Then just paste the following code inside it.
import Foundation
extension String {
func containsCharactersIn(matchCharacters: String) -> Bool {
let characterSet = NSCharacterSet(charactersInString: matchCharacters)
return self.rangeOfCharacterFromSet(characterSet) != nil
}
func containsOnlyCharactersIn(matchCharacters: String) -> Bool {
let disallowedCharacterSet = NSCharacterSet(charactersInString: matchCharacters).invertedSet
return self.rangeOfCharacterFromSet(disallowedCharacterSet) == nil
}
func doesNotContainCharactersIn(matchCharacters: String) -> Bool {
let characterSet = NSCharacterSet(charactersInString: matchCharacters)
return self.rangeOfCharacterFromSet(characterSet) == nil
}
func isNumeric() -> Bool
{
let scanner = NSScanner(string: self)
scanner.locale = NSLocale.currentLocale()
return scanner.scanDecimal(nil) && scanner.atEnd
}
}
Now save the class.....
Usage..
Now goto your viewController.swift class and make your textfield's outlets as..
@IBOutlet weak var contactEntryTxtFld: UITextField! //First textfield
@IBOutlet weak var contactEntryTxtFld2: UITextField! //Second textfield
Now goto the textfield's shouldChangeCharactersInRange method and use like the following.
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
if string.characters.count == 0 {
return true
}
let latestText = textField.text ?? ""
let checkAbleText = (latestText as NSString).stringByReplacingCharactersInRange(range, withString: string)
switch textField {
case contactEntryTxtFld:
return checkAbleText.containsOnlyCharactersIn("0123456789") && prospectiveText.characters.count <= 5
case contactEntryTxtFld2:
return checkAbleText.containsOnlyCharactersIn("0123456789") && prospectiveText.characters.count <= 5
default:
return true
}
}
Don't forget to set the delegate protocol/methods of textfields.
Let me explain about this... I am using the simple extension process of string which I wrote inside an another class. Now I am just calling those extension methods from another class where I need them by adding check and maximum value.
Features...
- It will set maximum limit of a particular textfield.
- It will set type of accepted keys for particular textfield.
Types...
containsOnlyCharactersIn //Accepts only Characters.
containsCharactersIn //Accepts combination of characters
doesNotContainsCharactersIn //Will not accept characters
Hope this helped.... Thanks..
we can set the range of textfield like this..
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
int setrange = 20;
return !([textField.text length]>setrange && [string length] > range.length);
}
You can't do this directly - UITextField has no maxLength attribute, but you can set the UITextField's delegate, then use:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
To complete August answer, an possible implementation of the proposed function (see UITextField's delegate).
I did not test domness code, but mine do not get stuck if the user reached the limit, and it is compatible with a new string that comes replace a smaller or equal one.
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
//limit the size :
int limit = 20;
return !([textField.text length]>limit && [string length] > range.length);
}
Source: Stackoverflow.com