UIView 不响应触摸

Question

I have simple view controller and I add this controller like subview for window using this code:

UIWindow *window = [UIApplication sharedApplication].keyWindow;
if (!window)
window = [[UIApplication sharedApplication].windows objectAtIndex:0];

self.view.alpha = 0.0;
self.view.userInteractionEnabled = YES;
[window addSubview:self.view];

[self.view addGestureRecognizer:[[UITapGestureRecognizer alloc]    initWithTarget:self action:@selector(closeTriggered:)]];

[UIView animateWithDuration:0.5 delay:0 options:UIViewAnimationOptionAllowUserInteraction animations:^{
  self.view.alpha = 1.0;
    }completion:nil];

But when I click at this view - nothing happens. Even event touchesBegan: are not called.

UPD: Code above is in -(void)show method. I want to show one controller above all controllers. In FirstViewController I create instance of CustonAlertViewController like that:

CustomAlertViewController *alertVC = [[CustomAlertViewController alloc]init];
[alertVC show];

In CustomAlertViewController I have show method presented at the top and viewDidLoad method with:

self.view.backgrondColor = [UIColor greenColor];

Answer 1

Hidden views (and equivalently, those with alpha == 0.0 ) do not respond to touches. If you require a fully transparent view, leave alpha as > 0.0, and say...

self.view.backgroundColor = [UIColor clearColor];

Alternatively, assign a nonzero alpha.

EDIT yes, the CustomAlertViewController instance is being deallocated immediately after show is invoked. The view controller that does the allocating needs to have a strong property to keep the alert around,

@property(nonatomic,strong) CustomAlertViewController *alertVC;

and adding...

CustomAlertViewController *alertVC = [[CustomAlertViewController alloc]init];
self.alertVC = alertVC;
[alertVC show];

This doesn't try to address some potential problems beyond the scope of this question (like rotation, or cleanly restoring when the alert is done).

Answer 2

// try like this , u need to give number of touches

  UITapGestureRecognizer *gesture = [[UITapGestureRecognizer alloc]   initWithTarget:self action:@selector(closeTriggered:)];
 gesture.numberOfTapsRequired = 1;
        gesture.numberOfTouchesRequired = 1;
[self.view addGestureRecognizer:gesture];

Answer 3

You have been setting your UITapGestureRecognizer after you addSubview to your window. like:

You have been doing this

//...
[window addSubview:self.view];

[self.view addGestureRecognizer:[[UITapGestureRecognizer alloc]    initWithTarget:self action:@selector(closeTriggered:)]];
//...

Try this

Set UITapGestureRecognizer before you addSubview . And remember to add the UIGestureRecognizerDelegate to your ViewController

self.view.alpha = 0.2;
self.view.userInteractionEnabled = YES;
UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(closeTriggered:)];
tapGesture.numberOfTapsRequired = 1;
[tapGesture setDelegate:self];
[self.view addGestureRecognizer:tapGesture];

// After you add your self.view to window
[window addSubview:self.view];

I hope this can help you.