setValueForKey error

1

I’m trying to implement an UIAlertController customization to show a switch control for one of the actions as described at https://medium.com/@maximbilan/ios-uialertcontroller-customization-5cfd88140db8#.3xe001k06

My Java class for SwitchAlertActionViewController look like this.
I am not completely sure what annotations (if any) I need to add there and also not sure what commented out swift line below would correspond to in the Java code.

public class SwitchAlertActionViewController extends UIViewController {
  // @IBOutlet weak var valueSwitch: UISwitch!
  UISwitch valueSwitch;
  boolean isSwitchOn = false; 
	
  public static native SwitchAlertActionViewController alloc();

  @Override
  public native SwitchAlertActionViewController init();

  protected SwitchAlertActionViewController(Pointer peer) {
    super(peer);
  }

  public void viewDidLoad() {
    super.viewDidLoad();
    valueSwitch.setOn(isSwitchOn);
 }
}

I also copied corresponding xib file from https://github.com/maximbilan/UIAlertController-Customization/tree/master/AlertControllerCustomization/Sources

Now, when I call UIAlertAction.setValueForKey:

UIViewController switchController = SwitchAlertActionViewController.alloc() //
  .initWithNibNameBundle("SwitchAlertActionViewController", NSBundle.mainBundle());
	
UIAlertAction combinedAction = UIAlertAction.actionWithTitleStyleHandler("Combined", UIAlertActionStyle.Default, null);
combinedAction.setValueForKey(switchController, "contentViewController");

I get the following error.
Could you please advise what am I doing wrong?

2016-12-27 16:06:59.417 MyApp[74409:6637335] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<SwitchAlertActionViewController 0x7bcf2350> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key valueSwitch.'
*** First throw call stack:
(
	0   CoreFoundation                      0x0794dbf2 __exceptionPreprocess + 194
	1   libobjc.A.dylib                     0x06e0ce66 objc_exception_throw + 52
	2   CoreFoundation                      0x0794db21 -[NSException raise] + 17
	3   Foundation                          0x0449f90d -[NSObject(NSKeyValueCoding) setValue:forUndefinedKey:] + 238
	4   Foundation                          0x043cd476 _NSSetUsingKeyValueSetter + 162
	5   Foundation                          0x043ccfe8 -[NSObject(NSKeyValueCoding) setValue:forKey:] + 285
	6   UIKit                               0x04a43a9e -[UIViewController setValue:forKey:] + 80
	7   Foundation                          0x043eeb5f -[NSObject(NSKeyValueC
oding) setValue:forKeyPath:] + 309
	8   UIKit                               0x04cf13ad -[UIRuntimeOutletConnection connect] + 138
	9   libobjc.A.dylib                     0x06e22177 -[NSObject performSelector:] + 51
	10  CoreFoundation                      0x078ed180 -[NSArray makeObjectsPerformSelector:] + 272
	11  UIKit                               0x04cefa6c -[UINib instantiateWithOwner:options:] + 2102
	12  UIKit                               0x04a4ad23 -[UIViewController _loadViewFromNibNamed:bundle:] + 437
	13  UIKit                               0x04a4b770 -[UIViewController loadView] + 197
	14  UIKit                               0x04a4bae9 -[UIViewController loadViewIfRequired] + 188
	15  UIKit                               0x04a4c50d -[UIViewController view] + 29
	16  UIKit                               0x04ec66ca -[_UIAlertControllerActionView _loadContentViewControllerView] + 118
	17  UIKit                               0x04ec7932 -[_UIAlertControllerActionView setAction:] + 847
	18  UIKit       
                        0x05479ab3 -[_UIAlertControllerView _actionsChanged] + 668
	19  UIKit                               0x04c404c8 -[UIAlertController loadView] + 356
	20  UIKit                               0x04a4bae9 -[UIViewController loadViewIfRequired] + 188
	21  UIKit                               0x04a4c50d -[UIViewController view] + 29
	22  UIKit                               0x04a68d3e -[UIViewController _setPresentationController:] + 117
	23  UIKit                               0x04a5f314 -[UIViewController _presentViewController:modalSourceViewController:presentationController:animationController:interactionController:completion:] + 1528
	24  UIKit                               0x04a6133c -[UIViewController _presentViewController:withAnimationController:completion:] + 5467
	25  UIKit                               0x04a64632 __62-[UIViewController presentViewController:animated:completion:]_block_invoke + 363
	26  UIKit                               0x04a6499b -[UIViewController _performCoordina
tedPresentOrDismiss:animated:] + 535
	27  UIKit                               0x04a64480 -[UIViewController presentViewController:animated:completion:] + 182
	28  MOE                                 0x066471d8 ffi_call_i386 + 24
)
libc++abi.dylib: terminating with uncaught exception of type NSException
2

Dear Eugene,

xibs and storyboards access properties through KVC. For MOE to add KVC support for a property, you need to bind it as:

@Selector("valueSwitch")
@Property
@IBOutlet
public native UISwitch valueSwitch();

Note the @Property annotation. This makes sure proper backing for the object is allocated in Objective-C, thus the method is native.

In case you also need the setter method, use this:

@Selector("setValueSwitch:")
public native void setValueSwitch(UISwitch value);

Best Regards,
Kristóf

3

Thank you Kristóf,

I changed switch action view controller as you advised. Also my code that calls it look like this:

UIViewController switchController = SwitchAlertActionViewController.alloc() //
  .initWithNibNameBundle("SwitchAlertActionViewController", NSBundle.mainBundle());
	
UIAlertAction combinedAction = UIAlertAction.actionWithTitleStyleHandler("Combined", UIAlertActionStyle.Default, null);
combinedAction.setValueForKey(switchController, "contentViewController");
	
UIAlertController alert = UIAlertController.alertControllerWithTitleMessagePreferredStyle(null, null, UIAlertControllerStyle.ActionSheet);
alert.addAction(combinedAction);
presentViewControllerAnimatedCompletion(alert, true, null);

But now I’m getting a different exception. This time it didn’t get to UIAlertAction.setValueForKey() call and failed on the UIViewController init. Any idea what am I doing wrong? I checked and my .xib does have valueSwitch connection, but I am total newbie in ios development.
You could use github repo from my first message to take a pick at the original ios code.

2017-01-02 11:34:04.149 XXX[20909:10464435] -[SwitchAlertActionViewController _setViewDelegate:]: unrecognized selector sent to instance 0x7d499450

2017-01-02 11:34:04.185 XXX[20909:10464435] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[SwitchAlertActionViewController _setViewDelegate:]: unrecognized selector sent to instance 0x7d499450'
*** First throw call stack:
(
	0   CoreFoundation                      0x07935bf2 __exceptionPreprocess + 194


	1   libobjc.A.dylib                     0x06df4e66 objc_exception_throw + 52
	2   CoreFoundation                      0x079af3bc -[NSObject(NSObject) doesNotRecognizeSelector:] + 172
	3   CoreFoundation                      0x078b44fc ___forwarding___ + 1052
	4   CoreFoundation                      0x078b40be _CF_forwarding_prep_0 + 14
	5   UIKit                               0x04a3da4f +[UIViewController setViewController:forView:] + 53
	6   UIKit                               0x04a34981 -[UIViewController setView:] + 564
	7   Foundation                          0x043b5476 _NSSetUsingKeyValueSetter + 162
	8   Foundation                          0x043b4fe8 -[NSObject(NSKeyValueCoding) setValue:forKey:] + 285
	9   UIKit                               0x04a2ba9e -[UIViewController setValue:forKey:] + 80
	10  Foundation                          0x043d6b5f -[NSObject(NSKeyValueCoding) setValue:forKeyPath:] + 309
	11  UIKit                               0x04cd93ad -[UIRuntimeOutletConnection connect] + 138
	12  li
bobjc.A.dylib                     0x06e0a177 -[NSObject performSelector:] + 51
	13  CoreFoundation                      0x078d5180 -[NSArray makeObjectsPerformSelector:] + 272
	14  UIKit                               0x04cd7a6c -[UINib instantiateWithOwner:options:] + 2102
	15  UIKit                               0x04a32d23 -[UIViewController _loadViewFromNibNamed:bundle:] + 437
	16  UIKit                               0x04a33770 -[UIViewController loadView] + 197
	17  UIKit                               0x04a33ae9 -[UIViewController loadViewIfRequired] + 188
	18  UIKit                               0x04a3450d -[UIViewController view] + 29
	19  UIKit                               0x04eae6ca -[_UIAlertControllerActionView _loadContentViewControllerView] + 118
	20  UIKit                               0x04eaf932 -[_UIAlertControllerActionView setAction:] + 847
	21  UIKit                               0x05461ab3 -[_UIAlertControllerView _actionsChanged] + 668
	22  UIKit                               0x04c284c8 -[
UIAlertController loadView] + 356
	23  UIKit                               0x04a33ae9 -[UIViewController loadViewIfRequired] + 188
	24  UIKit                               0x04a3450d -[UIViewController view] + 29
	25  UIKit                               0x04a50d3e -[UIViewController _setPresentationController:] + 117
	26  UIKit                               0x04a47314 -[UIViewController _presentViewController:modalSourceViewController:presentationController:animationController:interactionController:completion:] + 1528
	27  UIKit                               0x04a4933c -[UIViewController _presentViewController:withAnimationController:completion:] + 5467
	28  UIKit                               0x04a4c632 __62-[UIViewController presentViewController:animated:completion:]_block_invoke + 363
	29  UIKit                               0x04a4c99b -[UIViewController _performCoordinatedPresentOrDismiss:animated:] + 535
	30  UIKit                               0x04a4c480 -[UIViewController presentViewController:animate
d:completion:] + 182
	31  MOE                                 0x0662f1d8 ffi_call_i386 + 24
)
libc++abi.dylib: terminating with uncaught exception of type NSException
4

Dear Eugene,

Could you please share your project with us (or any project where we can reproduce this issue)?

Best Regards,
Kristóf

5

Thank you for looking into this. Here is a small test project. The error happen when you tap on “…” button.

UIAlertController.zip (122.2 KB)

I’m trying to make this UI:

6

Dear Eugene,

you set the custom class of the view in the xib file to SwitchAlertActionViewController, which was incorrect. Please remove the custom class.

Best Regards,
Kristóf

7

Wou! I can’t believe it was that simple. Thank you a lot for your help and for a great product!