最前面可见的 UIView 没有收到触摸，为什么？

Question

考虑以下视图层次结构

• self.view
  • self.transformedView（z-transform=10，索引 0）
  • self.ordinaryView（z-transform=0，索引 1）

通过这段代码实现

@interface AGSTransformedView : UIView
@end
@implementation AGSTransformedView

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    NSLog(@"The transformed view is receiving touch");
    [super touchesBegan:touches withEvent:event];
}

@end


@interface AGSOrdinaryView : UIView
@end
@implementation AGSOrdinaryView

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    NSLog(@"The ordinary view is receiving touch");
    [super touchesBegan:touches withEvent:event];
}

@end

@interface AGSViewController ()

@end

@implementation AGSViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    AGSTransformedView *transformed = [[AGSTransformedView alloc] initWithFrame:self.view.bounds];
    transformed.layer.transform = CATransform3DMakeTranslation(0, 0, 10);
    transformed.backgroundColor = [UIColor yellowColor];
    [self.view addSubview:transformed];

    AGSOrdinaryView *ordinary = [[AGSOrdinaryView alloc] initWithFrame:self.view.bounds];
    ordinary.backgroundColor = [UIColor blueColor];
    [self.view addSubview:ordinary];
}

@end

点击屏幕时，我在控制台中看到了这个

The ordinary view is receiving touch

在屏幕上我只看到黄色视图（变换视图）。

为什么最前面的可见视图没有收到触摸？

Answer 1

似乎 UIKit 在确定哪个视图应该是触摸的接收者时只尊重视图层次结构。我还没有找到这方面的文档。