How to pass prepareForSegue an object

Question

I have many annotations in a mapview  with rightCalloutAccessory buttons   The button will perform a segue from this mapview to a tableview   I want to pass the tableview a different object  that holds data  depending on which callout button was clicked   For example   totally made up    annotation1  Austin  -  pass data obj 1  relevant to Austin  annotation2  Dallas  -  pass data obj 2  relevant to Dallas  annotation3  Houston  -  pass data obj 3 and so on     you get the idea    I am able to detect which callout button was clicked   I m using prepareForSegue  to pass the data obj to the destination ViewController   Since I cannot make this call take an extra argument for the data obj I require  what are some elegant ways to achieve the same effect  dynamic data obj    Any tip would be appreciated

User · Answer

I used this solution so that I could keep the invocation of the segue and the data communication within the same function:

private var segueCompletion : ((UIStoryboardSegue, Any?) -> Void)?

func performSegue(withIdentifier identifier: String, sender: Any?, completion: @escaping (UIStoryboardSegue, Any?) -> Void) {
    self.segueCompletion = completion;
    self.performSegue(withIdentifier: identifier, sender: sender);
    self.segueCompletion = nil
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    self.segueCompletion?(segue, sender)
}

A use case would be something like:

func showData(id : Int){
    someService.loadSomeData(id: id) {
        data in
        self.performSegue(withIdentifier: "showData", sender: self) {
            storyboard, sender in
            let dataView = storyboard.destination as! DataView
            dataView.data = data
        }
    }
}

This seems to work for me, however, I'm not 100% sure that the perform and prepare functions are always executed on the same thread.

User · Answer

My solution is similar        In destination class   var AddressString String   String       In segue  override func prepareForSegue segue  UIStoryboardSegue  sender  AnyObject        if  segue identifier     seguetobiddetailpagefromleadbidder                 let secondViewController   segue destinationViewController as  BidDetailPage         secondViewController AddressString   pr address as String

User · Answer

Sometimes it is helpful to avoid creating a compile-time dependency between two view controllers  Here s how you can do it without caring about the type of the destination view controller   -  void prepareForSegue  UIStoryboardSegue   segue sender  id sender       if   segue destinationViewController respondsToSelector  selector setMyData                segue destinationViewController performSelector  selector setMyData                                                  withObject myData              So as long as your destination view controller declares a public property  e g     property  nonatomic  strong  MyData  myData    you can set this property in the previous view controller as I described above

User · Answer

Simply grab a reference to the target view controller in prepareForSegue  method and pass any objects you need to there  Here s an example     -  void prepareForSegue  UIStoryboardSegue   segue sender  id sender          Make sure your segue name in storyboard is the same as this line     if    segue identifier  isEqualToString   YOUR SEGUE NAME HERE                     Get reference to the destination view controller         YourViewController  vc    segue destinationViewController               Pass any objects to the view controller here  like             vc setMyObjectHere object             REVISION   You can also use performSegueWithIdentifier sender  method to activate the transition to a new view based on a selection or button press     For instance  consider I had two view controllers   The first contains three buttons and the second needs to know which of those buttons has been pressed before the transition   You could  wire the buttons up to an IBAction in your code which uses performSegueWithIdentifier  method  like this        When any of my buttons are pressed  push the next view -  IBAction buttonPressed  id sender        self performSegueWithIdentifier   MySegue  sender sender         This will get called too before the view appears -  void prepareForSegue  UIStoryboardSegue   segue sender  id sender       if    segue identifier  isEqualToString   MySegue                  Get destination view         SecondView  vc    segue destinationViewController               Get button tag number  or do whatever you need to do here  based on your object         NSInteger tagIndex     UIButton   sender tag               Pass the information to your destination view          vc setSelectedButton tagIndex             EDIT   The demo application I originally attached is now six years old  so I ve removed it to avoid any confusion

User · Answer

I ve implemented a library with a category on UIViewController that simplifies this operation  Basically  you set the parameters you want to pass over in a NSDictionary associated to the UI item that is performing the segue  It works with manual segues too   For example  you can do   self performSegueWithIdentifier   yourIdentifier  parameters     customParam1  customValue1    customValue2  customValue2      for a manual segue or create a button with a segue and use   button setSegueParameters     customParam1  customValue1    customValue2  customValue2      If destination view controller is not key-value coding compliant for a key  nothing happens  It works with key-values too  useful for unwind segues   Check it out here https   github com stefanomondino SMQuickSegue

User · Answer

For Swift use this   override func prepareForSegue segue  UIStoryboardSegue  sender  AnyObject         var segueID   segue identifier      if segueID      yourSegueName             var yourVC YourViewController   segue destinationViewController as YourViewController          yourVC objectOnYourVC   setObjectValueHere

User · Answer

In Swift 4 2 I would do something like that    override func prepare for segue  UIStoryboardSegue  sender  Any         if let yourVC   segue destination as  YourViewController           yourVC yourData   self someData

User · Answer

I came across this question when I was trying to learn how to pass data from one View Controller to another  I need something visual to help me learn though  so this answer is a supplement to the others already here  It is a little more general than the original question but it can be adapted to work   This basic example works like this     The idea is to pass a string from the text field in the First View Controller to the label in the Second View Controller   First View Controller  import UIKit  class FirstViewController  UIViewController         IBOutlet weak var textField  UITextField          This function is called before the segue     override func prepareForSegue segue  UIStoryboardSegue  sender  AnyObject                 get a reference to the second view controller         let secondViewController   segue destinationViewController as  SecondViewController             set a variable in the second view controller with the String to pass         secondViewController receivedString   textField text             Second View Controller  import UIKit  class SecondViewController  UIViewController         IBOutlet weak var label  UILabel          This variable will hold the data being passed from the First View Controller     var receivedString           override func viewDidLoad             super viewDidLoad               Used the text from the First View Controller to set the label         label text   receivedString            Remember to   Make the segue by control clicking on the button and draging it over to the Second View Controller  Hook up the outlets for the UITextField and the UILabel  Set the first and second View Controllers to the appropriate Swift files in IB    Source  How to send data through segue  swift   YouTube tutorial   See also  View Controllers  Passing data forward and passing data back  fuller answer

User · Answer

I have a sender class  like this   class MyEntry    interface MySenderEntry   NSObject  property  strong  nonatomic  MyEntry  entry   end   implementation MySenderEntry  end   I use this sender class for passing objects to prepareForSeque sender   - void didSelectItemAtIndexPath  NSIndexPath  indexPath       MySenderEntry  sender    MySenderEntry new       sender entry     entries objectAtIndex indexPath row        self performSegueWithIdentifier SEGUE IDENTIFIER SHOW ENTRY sender sender      - void prepareForSegue  UIStoryboardSegue  segue sender  id sender       if    segue identifier  isEqualToString SEGUE IDENTIFIER SHOW ENTRY             NSAssert  sender isKindOfClass  MySenderEntry class      MySenderEntry            MySenderEntry  senderEntry    MySenderEntry  sender          MyEntry  entry   senderEntry entry          NSParameterAssert entry             segue destinationViewController  delegate   self           segue destinationViewController  entry   entry          return             if    segue identifier  isEqualToString SEGUE IDENTIFIER HISTORY                            return             if    segue identifier  isEqualToString SEGUE IDENTIFIER FAVORITE                            return

User · Answer

Just use this function    override func prepare for segue  UIStoryboardSegue  sender  Any         let index   CategorytableView indexPathForSelectedRow     let indexNumber   index  row     let VC   segue destination as  DestinationViewController    VC value   self data

[ios] How to pass prepareForSegue: an object

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