Question

我正在尝试将触摸事件添加到从屏幕右侧向左侧漂移的小视图块。问题是layer.presentationLayer hitTest:point方法没有返回任何内容，即使我确实在视图块的范围内进行了挖掘。

最后，我找到了解决方法。但是，两个问题仍然让我感到困惑。

转换后的点似乎不对，如何正确使用presentationLayer hitTest？
在我的代码段中，UIViewAnimationOptionAllowUserInteraction未设置，为什么我还能处理触摸事件？

以下是代码，任何帮助将不胜感激

`viewDidLoad`

CGRect bounds = [[UIScreen mainScreen] bounds];

for (int i = 0; i < 15; i++) {

    ViewBlock *view = [[ViewBlock alloc] initWithFrame:CGRectMake(bounds.size.width, 200, 40, 40)];
    [self.view addSubview:view];


    [UIView animateWithDuration:20 delay:i * 21 options:UIViewAnimationOptionCurveLinear animations:^{
        view.frame = CGRectMake(-40, 200, 40, 40);
    } completion:^(BOOL finished) {
        [view removeFromSuperview];
    }];
}

ViewBlock.m

@implementation ViewBlock
- (instancetype)initWithFrame:(CGRect)frame{

    if (self = [super initWithFrame:frame]) {
        self.backgroundColor = [UIColor redColor];
    }
    return self;
}

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event{
    CALayer *presentationLayer = self.layer.presentationLayer; //Do NOT modify presentationLayer
    if (presentationLayer) {
        CGPoint layer_point = [presentationLayer convertPoint:point fromLayer:self.layer.modelLayer];
        if ([presentationLayer hitTest:point]) {
            return self; //not worked
        }

        if ([presentationLayer hitTest:layer_point]) {
            return self; //not worked either
        }

        if (CGRectContainsPoint(presentationLayer.bounds, layer_point)) {
            return self;  //the workaround
        }
    }
    return [super hitTest:point withEvent:event];
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    [super touchesBegan:touches withEvent:event];
    NSLog(@"touches began");
}

- (void)didMoveToSuperview{
    [super didMoveToSuperview];

    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapTouched:)]
    ;
    tap.cancelsTouchesInView = NO;

    [self addGestureRecognizer:tap];
}

- (void)tapTouched:(UITapGestureRecognizer *)sender{
    NSLog(@"touches gesture");
}
@end

Answer 1

Q1：转换后的点似乎不对，如何正确使用presentationLayer hitTest？

你缺少的是hitTest:的参数应该在接收者的超级层的坐标系中，所以代码应该是：

CGPoint superLayerP = [presentationLayer.superlayer convertPoint:layer_point fromLayer:presentationLayer];
if ([presentationLayer hitTest:superLayerP]) {
    return self;
}

Q2：在我的代码片段中，未设置UIViewAnimationOptionAllowUserInteraction，为什么我可以处理触摸事件

我认为您可以获取触摸事件，因为您覆盖- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event并返回self作为结果，因此事件将传递给它。默认情况下（如果不覆盖hitTest：withEvent：方法），则不会触及事件。

如果你设置UIViewAnimationOptionAllowUserInteraction选项，你可以在视图的最后一帧（CGRectMake（-40,200,40,40））上获得触摸事件，但在这个例子中，最后一帧不在屏幕上，您可以将其设置为CGRectMake(0, 200, 40, 40)并进行测试。

iOS动画演示文稿层命中测试似乎没有按预期工作

`viewDidLoad`

ViewBlock.m

1 个答案: