How to use pull to refresh in Swift

Question

I am building an RSS reader using swift and need to implement pull to reload functionality   Here is how i am trying to do it   class FirstViewController  UIViewController      UITableViewDelegate  UITableViewDataSource        IBOutlet var refresh  UIScreenEdgePanGestureRecognizer     IBOutlet var newsCollect  UITableView     var activityIndicator UIActivityIndicatorView    nil     override func viewDidLoad            super viewDidLoad          self newsCollect scrollEnabled   true          Do any additional setup after loading the view  typically from a nib         if nCollect news count  lt   2            self collectNews                  else            self removeActivityIndicator                  view addGestureRecognizer refresh           IBAction func reload sender  UIScreenEdgePanGestureRecognizer        nCollect news   News         return newsCollect reloadData       I am getting        Property  self refresh  not initialized at super init call   Please help me to understand the behaviour of Gesture recognisers  A working sample code will be a great help   Thanks

User · Answer

Due to less customisability  code duplication and bugs which come with pull to refresh control  I created a library PullToRefreshDSL which uses DSL pattern just like SnapKit    You only have to add the callback  rest is taken care of tableView ptr headerCallback      weak self  in    weakify self to avoid strong reference     DispatchQueue main asyncAfter deadline   now      seconds 2        your network call         self  tableView ptr isLoadingHeader   false    setting false will hide the view          You only have to add magical keyword ptr after any UIScrollView subclass i e  UITableView UICollectionView You dont have to download the library  you can explore and modify the source code  I am just pointing towards a possible implementation of pull to refresh for iOS

User · Answer

For the pull to refresh i am using   DGElasticPullToRefresh   https   github com gontovnik DGElasticPullToRefresh  Installation  pod  DGElasticPullToRefresh   import DGElasticPullToRefresh      and put this function into your swift file and call this funtion from your    override func viewWillAppear   animated  Bool        func Refresher           let loadingView   DGElasticPullToRefreshLoadingViewCircle         loadingView tintColor   UIColor red  255 0 255 0  green  255 0 255 0  blue  255 0 255 0  alpha  1 0        self table dg addPullToRefreshWithActionHandler    weak self     - gt  Void in              Completion block you can perfrom your code here              print  Stack Overflow               self  table dg stopLoading                 loadingView  loadingView        self table dg setPullToRefreshFillColor UIColor red  255 0 255 0  green  57 0 255 0  blue  66 0 255 0  alpha  1         self table dg setPullToRefreshBackgroundColor self table backgroundColor        And dont forget to remove reference while view will get dissapear  to remove pull to refresh put this code in to your   override func viewDidDisappear   animated  Bool   override func viewDidDisappear   animated  Bool          table dg removePullToRefresh         And it will looks like    Happy coding

User · Answer

Anhil s answer helped me a lot   However  after experimenting further I noticed that the solution suggested sometimes causes a not-so-pretty UI glitch   Instead  going for this approach  did the trick for me    Swift 2 1    Create an instance of a UITableViewController  This will host your UITableView  private let tableViewController   UITableViewController      Add tableViewController as a childViewController and set its tableView property to your UITableView  self addChildViewController self tableViewController  self tableViewController tableView   self tableView self refreshControl addTarget self  action   refreshData    forControlEvents   ValueChanged  self tableViewController refreshControl   self refreshControl

User · Answer

I built a RSS feed app in which I have a Pull To refresh feature that originally had some of the problems listed above    But to add to the users answers above  I was looking everywhere for my use case and could not find it  I was downloading data from the web  RSSFeed  and I wanted to pull down on my tableView of stories to refresh    What is mentioned above cover the right areas but with some of the problems people are having  here is what I did and it works a treat   I took  Blankarsch  s approach and went to my main storyboard and select the table view to use refresh  then what wasn t mentioned is creating IBOutlet and IBAction to use the refresh efficiently   x000D   x000D    Created from main storyboard cntrl drag refresh from left scene to assistant editor x000D   IBOutlet weak var refreshButton  UIRefreshControl x000D   x000D  override func viewDidLoad     x000D            x000D           x000D      Include your code x000D           x000D           x000D      Is the function called below  make sure to put this in your viewDidLoad  x000D      method or not data will be visible when running the app x000D    getFeedData   x000D    x000D   x000D    Function the gets my data parse my data from the web  if you havnt already put this in a similar function  x000D    remembering it returns nothing  hence return type is  - gt  Void  x000D  func getFeedData   - gt  Void  x000D          x000D          x000D    x000D   x000D    From main storyboard cntrl drag to assistant editor and this time create an action instead of outlet and  x000D    make sure arguments are set to none and note sender x000D   IBAction func refresh     x000D      getting our data by calling the function which gets our data parse our data x000D    getFeedData   x000D   x000D      note  refreshControl doesnt need to be declared it is already initailized  Got to love xcode x000D    refreshControl  endRefreshing   x000D    x000D   x000D   x000D    Hope this helps anyone in same situation as me

User · Answer

In Swift use this   If you wants to have pull to refresh in WebView   So try this code   override func viewDidLoad         super viewDidLoad       addPullToRefreshToWebView      func addPullToRefreshToWebView        var refreshController UIRefreshControl   UIRefreshControl        refreshController bounds   CGRectMake 0  50  refreshController bounds size width  refreshController bounds size height     Change position of refresh view     refreshController addTarget self  action  Selector  refreshWebView     forControlEvents  UIControlEvents ValueChanged      refreshController attributedTitle   NSAttributedString string   Pull down to refresh          YourWebView scrollView addSubview refreshController      func refreshWebView refresh UIRefreshControl       YourWebView reload       refresh endRefreshing

User · Answer

Others Answers Are Correct But for More Detail check this Post Pull to Refresh  Enable refreshing in Storyboard  When you   re working with a UITableViewController  the solution is fairly simple  First  Select the table view controller in your storyboard  open the attributes inspector  and enable refreshing  A UITableViewController comes outfitted with a reference to a UIRefreshControl out of the box  You simply need to wire up a few things to initiate and complete the refresh when the user pulls down   Override viewDidLoad    In your override of viewDidLoad    add a target to handle the refresh as follows  override func viewDidLoad         super viewDidLoad          Do any additional setup after loading the view  typically from a nib               self refreshControl  addTarget self  action   quot handleRefresh  quot   forControlEvents  UIControlEvents ValueChanged      Since I   ve specified    handleRefresh      note the colon   as the action argument  I need to define a function in this UITableViewController class with the same name  Additionally  the function should take one argument We   d like this action to be called for the UIControlEvent called ValueChanged Don t forget to call refreshControl endRefreshing    For more information Please go to mention Link and all credit goes to that post

User · Answer

What the error is telling you  is that refresh isn t initialized  Note that you chose to make refresh not optional  which in Swift means that it has to have a value before you call super init  or it s implicitly called  which seems to be your case   Either make refresh optional  probably what you want  or initialize it in some way   I would suggest reading the Swift introductory documentation again  which covers this in great length   One last thing  not part of the answer  as pointed out by  Anil  there is a built in pull to refresh control in iOS called UIRefresControl  which might be something worth looking into

User · Answer

I suggest to make an Extension of pull To Refresh to use in every class   1  Make an empty swift file    File - New - File - Swift File    2  Add the Following          AppExtensions swift      import Foundation     import UIKit          var tableRefreshControl UIRefreshControl   UIRefreshControl              MARK - VIEWCONTROLLER EXTENSION METHODS     public extension UIViewController               func makePullToRefreshToTableView tableName  UITableView triggerToMethodName  String                tableRefreshControl attributedTitle   NSAttributedString string   TEST  Pull to refresh               tableRefreshControl backgroundColor   UIColor whiteColor               tableRefreshControl addTarget self  action  Selector triggerToMethodName   forControlEvents  UIControlEvents ValueChanged              tableName addSubview tableRefreshControl                    func makePullToRefreshEndRefreshing  tableName  String                        tableRefreshControl endRefreshing     additional codes                        3  In Your View Controller call these methods as       override func viewWillAppear animated  Bool     self makePullToRefreshToTableView bidderListTable  triggerToMethodName   pullToRefreshBidderTable       4  At some point you wanted to end refreshing     func pullToRefreshBidderTable     self makePullToRefreshEndRefreshing  bidderListTable         Code What to do here    OR     self makePullToRefreshEndRefreshing  bidderListTable

User · Answer

func pullToRefresh         let refresh   UIRefreshControl       refresh addTarget self  action   selector handleTopRefresh       for   valueChanged       refresh tintColor   UIColor appBlack     self tblAddressBook addSubview refresh      objc func handleTopRefresh   sender UIRefreshControl       self callAddressBookListApi isLoaderRequired  false      sender endRefreshing

User · Answer

Swift 4  var refreshControl  UIRefreshControl   override func viewDidLoad         super viewDidLoad        refreshControl   UIRefreshControl       refreshControl attributedTitle   NSAttributedString string   Pull to refresh       refreshControl addTarget self  action   selector refresh   for   valueChanged      tableView addSubview refreshControl       objc func refresh   sender  Any            your code to reload tableView     And you could stop refreshing with   refreshControl endRefreshing

User · Answer

Swift 5  private var pullControl   UIRefreshControl    pullControl attributedTitle   NSAttributedString string   Pull to refresh           pullControl addTarget self  action   selector refreshListData       for   valueChanged          if  available iOS 10 0                   tableView refreshControl   pullControl           else               tableView addSubview pullControl               Actions  objc private func refreshListData   sender  Any            self pullControl endRefreshing      You can stop after API Call            Call API

User · Answer

You can achieve this by using few lines of code  So why you are going to stuck in third party library or UI  Pull to refresh is built in iOS  You could do this in swift like    var pullControl   UIRefreshControl    override func viewDidLoad        super viewDidLoad       pullControl attributedTitle   NSAttributedString string   Pull to refresh      pullControl addTarget self  action   selector pulledRefreshControl       for  UIControl Event valueChanged     tableView addSubview pullControl     not required when using UITableViewController     objc func pulledRefreshControl sender AnyObject          Code to refresh table view

User · Answer

I would like to mention a PRETTY COOL feature that has been included since iOS 10  which is   For now  UIRefreshControl is directly supported in each of UICollectionView  UITableView and UIScrollView   Each one of these views have refreshControl instance property  which means that there is no longer a need to add it as a subview in your scroll view   all you have to do is    IBOutlet weak var collectionView  UICollectionView   override func viewDidLoad         super viewDidLoad        let refreshControl   UIRefreshControl       refreshControl addTarget self  action   selector doSomething   for   valueChanged          this is the replacement of implementing   collectionView addSubview refreshControl       collectionView refreshControl   refreshControl    func doSomething refreshControl  UIRefreshControl        print  Hello World            somewhere in your code you might need to call      refreshControl endRefreshing       Personally  I find it more natural to treat it as a property for scroll view more than add it as a subview  especially because the only appropriate view to be as a superview for a UIRefreshControl is a scrollview  i e the functionality of using UIRefreshControl is only useful when working with a scroll view  That s why this approach should be more obvious to setup the refresh control view   However  you still have the option of using the addSubview based on the iOS version   if  available iOS 10 0         collectionView refreshControl   refreshControl   else     collectionView addSubview refreshControl

User · Answer

you can use this subclass of tableView   import UIKit  protocol PullToRefreshTableViewDelegate   class       func tableViewDidStartRefreshing tableView  PullToRefreshTableView     class PullToRefreshTableView  UITableView         IBOutlet weak var pullToRefreshDelegate  AnyObject      private var refreshControl  UIRefreshControl      private var isFirstLoad   true      override func willMoveToSuperview newSuperview  UIView             super willMoveToSuperview newSuperview           if  isFirstLoad                addRefreshControl               isFirstLoad   false                      private func addRefreshControl             refreshControl   UIRefreshControl           refreshControl attributedTitle   NSAttributedString string   Pull to refresh           refreshControl addTarget self  action   refresh   forControlEvents   ValueChanged          self addSubview refreshControl              objc private func refresh             pullToRefreshDelegate as  PullToRefreshTableViewDelegate   tableViewDidStartRefreshing self             func endRefreshing             refreshControl endRefreshing              1 - in interface builder change the class of your tableView to PullToRefreshTableView or create a PullToRefreshTableView programmatically  2 - implement the PullToRefreshTableViewDelegate in your view controller  3 - tableViewDidStartRefreshing tableView  PullToRefreshTableView  will be called in your view controller when the table view starts refreshing  4 - call yourTableView endRefreshing   to finish the refreshing

User · Answer

A solution with storyboard and Swift   Open your  storyboard file  select a TableViewController in your storyboard and  quot Enable quot  the Table View Controller  Refreshing feature in the Utilities    Open the associated UITableViewController class and add the following Swift 5 line into the viewDidLoad method  self refreshControl  addTarget self  action   selector refresh   for  UIControl Event valueChanged    Add the following method above the viewDidLoad method func refresh sender AnyObject           Updating your data here         self tableView reloadData       self refreshControl  endRefreshing

User · Answer

Pull to refresh is built in iOS  You could do this in swift like    var refreshControl   UIRefreshControl    override func viewDidLoad        super viewDidLoad       refreshControl attributedTitle   NSAttributedString string   Pull to refresh      refreshControl addTarget self  action   selector self refresh       for   valueChanged     tableView addSubview refreshControl     not required when using UITableViewController     objc func refresh   sender  AnyObject          Code to refresh table view       At some point you could end refreshing   refreshControl endRefreshing

User · Answer

Details   Xcode Version 10 3  10G8   Swift 5   Features   Ability to make  pull to refresh  programmatically Protection from multi-  pull to refresh  events Ability to continue animating of the activity indicator when view controller switched  e g  in case of TabController    Solution  import UIKit  class RefreshControl  UIRefreshControl        private weak var actionTarget  AnyObject      private var actionSelector  Selector      override init     super init          convenience init actionTarget  AnyObject   actionSelector  Selector            self init           self actionTarget   actionTarget         self actionSelector   actionSelector         addTarget              private func addTarget             guard let actionTarget   actionTarget  let actionSelector   actionSelector else   return           addTarget actionTarget  action  actionSelector  for   valueChanged             required init  coder aDecoder  NSCoder    super init coder  aDecoder         func endRefreshing deadline  DispatchTime    nil            guard let deadline   deadline else   endRefreshing    return           DispatchQueue global qos   default  asyncAfter deadline  deadline     weak self  in             DispatchQueue main async   self  endRefreshing                          func refreshActivityIndicatorView             guard let selector   actionSelector else   return           let  isRefreshing   isRefreshing         removeTarget actionTarget  action  selector  for   valueChanged          endRefreshing           if  isRefreshing   beginRefreshing             addTarget              func generateRefreshEvent             beginRefreshing           sendActions for   valueChanged           public extension UIScrollView        private var  refreshControl  RefreshControl    return refreshControl as  RefreshControl        func addRefreshControll actionTarget  AnyObject   action  Selector  replaceIfExist  Bool   false            if  replaceIfExist  amp  amp  refreshControl    nil   return           refreshControl   RefreshControl actionTarget  actionTarget  actionSelector  action             func scrollToTopAndShowRunningRefreshControl changeContentOffsetWithAnimation  Bool   false             refreshControl  refreshActivityIndicatorView           guard   let refreshControl   refreshControl                  contentOffset y    -refreshControl frame height else   return           setContentOffset CGPoint x  0  y  -refreshControl frame height   animated  changeContentOffsetWithAnimation             private var canStartRefreshing  Bool           guard let refreshControl   refreshControl   refreshControl isRefreshing else   return false           return true            func startRefreshing             guard canStartRefreshing else   return            refreshControl  generateRefreshEvent              func pullAndRefresh             guard canStartRefreshing else   return           scrollToTopAndShowRunningRefreshControl changeContentOffsetWithAnimation  true           refreshControl  generateRefreshEvent              func endRefreshing deadline  DispatchTime    nil     refreshControl  endRefreshing deadline  deadline        Usage     Add refresh control to UICollectionView   UITableView   UIScrollView private func setupTableView         let tableView   UITableView                  tableView addRefreshControll actionTarget  self  action   selector refreshData       objc func refreshData   refreshControl  UIRefreshControl        tableView  endRefreshing deadline   now      seconds 3         Stop refreshing in UICollectionView   UITableView   UIScrollView tableView endRefreshing       Simulate pull to refresh in UICollectionView   UITableView   UIScrollView tableView pullAndRefresh     Full Sample     Do not forget to add the solution code here   import UIKit  class ViewController  UIViewController        private weak var tableView  UITableView       override func viewDidLoad             super viewDidLoad           setupTableView              private func setupTableView             let tableView   UITableView           view addSubview tableView          tableView translatesAutoresizingMaskIntoConstraints   false         tableView topAnchor constraint equalTo  view topAnchor  isActive   true         tableView leftAnchor constraint equalTo  view leftAnchor  isActive   true         tableView rightAnchor constraint equalTo  view rightAnchor  isActive   true         tableView bottomAnchor constraint equalTo  view bottomAnchor  isActive   true         tableView dataSource   self         tableView delegate   self         tableView addRefreshControll actionTarget  self  action   selector refreshData           self tableView   tableView          extension ViewController        objc func refreshData   refreshControl  UIRefreshControl            print  refreshing           tableView  endRefreshing deadline   now      seconds 3            extension ViewController  UITableViewDataSource       func numberOfSections in tableView  UITableView  - gt  Int   return 1       func tableView   tableView  UITableView  numberOfRowsInSection section  Int  - gt  Int   return 20       func tableView   tableView  UITableView  cellForRowAt indexPath  IndexPath  - gt  UITableViewCell           let cell   UITableViewCell           cell textLabel  text      indexPath           return cell          extension ViewController  UITableViewDelegate       func tableView   tableView  UITableView  didSelectRowAt indexPath  IndexPath            tableView pullAndRefresh

User · Answer

This is how I made it work using Xcode 7 2 which I think is a major bug  I m using it inside my UITableViewController inside my viewWillAppear  refreshControl   UIRefreshControl   refreshControl  addTarget self  action   configureMessages   forControlEvents   ValueChanged  refreshControl  beginRefreshing    configureMessages    func configureMessages            configuring messages logic here      self refreshControl  endRefreshing       As you can see  I literally have to call the configureMessage   method after setting up my UIRefreshControl then after that  subsequent refreshes will work fine

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