objective-c - UITapGestureRecognizer 不适用于 UILabel

Question

我正在尝试将 UITapGestureRecognizer 添加到 UILabel，如果用户有新通知，它将从状态栏向下动画。我希望用户能够单击标签并直接转到公告。 UITapGetureRecognizer 不工作。这是我正在做的:

+(void)animateDown:(NSString *)title view:(UIViewController *)view color:(UIColor *)color time:(NSTimeInterval)duration
{
    view = view.navigationController.visibleViewController;
    if (currentlyDisplayed == NO) {
        if (color == nil) color = customGreen;
        UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0 ,-40, 320, 40)];
        label.text = title;
        label.font = [UIFont fontWithName:@"STHeitiTC-Medium" size:18];
        label.backgroundColor = color;//customBlue;//[UIColor colorWithRed:0.0993145 green:0.0957361 blue:0.562879 alpha:.8f];
        label.layer.cornerRadius = 15.0f;
        [label setTextAlignment:NSTextAlignmentCenter];
        [label setMinimumFontSize:12];
        [label setAdjustsFontSizeToFitWidth:YES];
        [label sizeToFit];
        label.textColor = [UIColor whiteColor];
        if ([color isEqual:customBlue]) {
            UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(onTap:)];
            tap.numberOfTapsRequired = 1;
            tap.numberOfTouchesRequired = 1;
            label.userInteractionEnabled = YES;
            [label addGestureRecognizer:tap];
        }
        [view.view addSubview:label];
        [view.view bringSubviewToFront:label];
        currentlyDisplayed = YES;
        [UIView animateWithDuration:.5f delay:0 options:UIViewAnimationOptionAllowUserInteraction|UIViewAnimationOptionCurveEaseIn animations:^{
            label.frame = CGRectMake(0, 0, 320, 40);
        }completion:^(BOOL finished) {
            CGFloat dur;
            if (duration == 0)  {
                dur = .5f;
            }else {
                dur = duration;
            }

            [UIView animateWithDuration:1 delay:dur options:UIViewAnimationOptionAllowUserInteraction|UIViewAnimationOptionCurveEaseOut animations:^{
                label.frame = CGRectMake(0,-40,320,40);
            }completion:^(BOOL finished) {
                if (finished) [label removeFromSuperview];
                currentlyDisplayed = NO;
            }];
        }]; 
    }else {
        NSMethodSignature *sig = [[self class] methodSignatureForSelector:@selector(animateDown:view:color:time:)];
        NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:sig];
        [invocation setSelector:@selector(animateDown:view:color:time:)];
        [invocation setTarget:self];
        [invocation setArgument:&title atIndex:2];
        [invocation setArgument:&view atIndex:3];
        [invocation setArgument:&color atIndex:4];
        [invocation setArgument:&duration atIndex:5];
        [NSTimer scheduledTimerWithTimeInterval:0.5 invocation:invocation repeats:NO];
    }
}



- (IBAction)onTap:(UIPanGestureRecognizer *)recognizer {
    [[NSNotificationCenter defaultCenter] postNotification:[NSNotification notificationWithName:@"announcementTapped" object:nil]];
    NSLog(@"tapped");
}

永远不会调用 onTap 方法......它进入 if 语句......参见图片:

Answer 1

它无法识别触摸，因为它在 UIView 动画 block 中被点击。

尝试在设置动画时将 UIViewAnimationOptionAllowUserInteraction 添加到选项参数。

---

编辑

问题是 UIView 层的实际位置在最终目的地。你要做的是检查它的 presentationLayer 是否在被点击的位置。

要解决这个问题，您可以将手势添加到主视图而不是实际标签，并在点击时检查触摸位置是否在标签的 presentationLayer 内:

- (IBAction)onTap:(UITapGestureRecognizer *)tapGestureRecognizer {
    CGPoint point = [tapGestureRecognizer locationInView:tapGestureRecognizer.view];
    BOOL labelTapped = [self.label.layer.presentationLayer hitTest:point] != nil;
    if (labelTapped) {
        // do something
    }
}