UITapGestureRecognizer和UIPanGestureRecognizer

Question

我想創建並看到一個uiimageview，當我點擊屏幕。 在我擡起手指之前，我想在屏幕周圍移動uiimageview，並且只在手指離開時才移動圖像。繼承人我做了什麼：

- (IBAction)tap:(UITapGestureRecognizer *)recognizer { 

    CGPoint location = [recognizer locationInView:self.view]; 

    UIImageView *circle = [[UIImageView alloc] initWithFrame:CGRectMake(location.x, location.y, 50, 50)]; 
    circle.userInteractionEnabled = YES; 
    [circle setImage:[UIImage imageNamed:@"monkey_1.png"]]; 
    [self.view addSubview:circle]; 

    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:circle action:nil]; 
    [recognizer requireGestureRecognizerToFail:pan]; 

    CGPoint translation = [pan translationInView:circle]; 
    pan.view.center = CGPointMake(pan.view.center.x + translation.x, pan.view.center.y + translation.y); 
    [pan setTranslation:CGPointMake(0, 0) inView:self.view]; 
} 

Answer 1

你可以只是一個UIPanGestureRecognizer或UILongPressGestureRecognizer做到這一點。在手勢處理方法中，檢查識別器的state屬性，並在UIGestureRecognizerStateEnded（即用戶將手指從屏幕上擡起）時顯示圖像。例如：

- (void)handleGesture:(UILongPressGestureRecognizer *)recognizer { 
    if(recognizer.state == UIGestureRecognizerStateEnded) { 
     // gesture ended: show the image 
    } 
    else if(recognizerState == UIGestureRecognizerStateBegan) { 
     // this code runs when the gesture is started. 
    } 
    else if(recognizerState == UIGestureRecognizerStateChanged) { 
     // gesture is in progress 
    } 
}