在某段時間後取消UILongPressGestureRecognizer

Question

我在我的UICollectionView中使用了UILongPressGestureRecognizer。現在我的時候我一定的時間後，握住我的的CollectionView項目手指（例如1秒），我希望我的UILongPressGestureRecognizer結束和執行一定的代碼：

if (gestureRecognizer.state == UIGestureRecognizerStateEnded) {} 

這是我的代碼：

- (void)viewDidLoad { 
    [super viewDidLoad]; 
    Public = [[PublicMethods alloc]init]; 
    self.view.backgroundColor = [UIColor whiteColor]; 
    [self.view addSubview:self.collect]; 

    UILongPressGestureRecognizer *lpgr = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(handleLongPress:)]; 
    lpgr.minimumPressDuration = 3; //seconds 
    lpgr.delaysTouchesBegan = YES; 
    lpgr.delegate = self; 
    [self.collect addGestureRecognizer:lpgr]; 


} 
-(void)handleLongPress:(UILongPressGestureRecognizer *)gestureRecognizer { 
    if (gestureRecognizer.state != UIGestureRecognizerStateEnded) { 
    return; 
    } 

    CGPoint p = [gestureRecognizer locationInView:self.collect]; 
    NSIndexPath *indexPath = [self.collect indexPathForItemAtPoint:p]; 
    if (indexPath == nil){ 
    NSLog(@"couldn't find index path"); 
    } else { 
    // get the cell at indexPath (the one you long pressed) 
    //CollectionViewCell* cell = (CollectionViewCell*)[self.collect cellForItemAtIndexPath:indexPath]; 
    UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"bala" message:@"jalaaaa" delegate:self cancelButtonTitle:@"ok" otherButtonTitles:nil, nil]; 
    [alert show]; 
    } 
} 

Answer 1

你可以在所述UILongPressGestureRecognizer開始實例化一個計時器然後取消該手勢，並且一旦定時器完成時，前執行「結束手勢」代碼（使用1秒的時間限制）：

- (void)handleLongPress:(UILongPressGestureRecognizer *)gestureRecognizer { 
    if (gestureRecognizer.state == UIGestureRecognizerStateBegan) { 
     // Create a timer that calls cancel: 2.5 second after the 
     // gesture begins (i.e. 3 seconds after the button press if 
     // if lpgr.minimumPressDuration = .5;. Pass the gesture 
     // recognizer along within the user info dictionary parameter. 
     timer = [NSTimer scheduledTimerWithTimeInterval:2.5 target:self selector:@selector(cancel:) userInfo:[NSDictionary dictionaryWithObjectsAndKeys:gestureRecognizer, @"gestureRecognizer", nil] repeats:NO]; 

    } else if (gestureRecognizer.state == UIGestureRecognizerStateEnded) { 
     // Assuming you still want to execute the end code 
     // if the user lifts their finger before the 3 seconds 
     // is complete, use the same method called in the timer. 
     [self cancel:nil]; 
    } 
} 

- (void)cancel:(NSTimer*)timerObject { 

    NSLog(@"%@",[timer.userInfo objectForKey:@"gestureRecognizer"]); 
    // Get the gesture recognizer from the info dictionary 
    UIGestureRecognizer *gestureRecognizer = [timer.userInfo objectForKey:@"gestureRecognizer"]; 

    CGPoint p = [gestureRecognizer locationInView:self.collect]; 
    NSIndexPath *indexPath = [self.collect indexPathForItemAtPoint:p]; 
    if (indexPath == nil){ 
     NSLog(@"couldn't find index path"); 
    } else { 
     // get the cell at indexPath (the one you long pressed) 
     //CollectionViewCell* cell = (CollectionViewCell*)[self.collect cellForItemAtIndexPath:indexPath]; 
     UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"bala" message:@"jalaaaa" delegate:self cancelButtonTitle:@"ok" otherButtonTitles:nil, nil]; 
     [alert show]; 
    } 

    // Disable it and re-enable it to cancel the gesture 
    gestureRecognizer.enabled = NO; 
    gestureRecognizer.enabled = YES; 

    // Invalidate the timer 
    [timer invalidate]; 
    timer = nil; 
}