iOS核心动画技巧学习 - CALayer处理事件

CALayer 并不关心任何的响应链事件,所以也不能直接处理触摸事件或者手势;但是它有俩个方法帮你处理事件 -containsPoint 和 hitTest

-containtPoint

• 接收一个本图层坐标系下的 CGPoint,如果这个点在图层的 frame 范围内返回 YES

  - (void)viewDidLoad {
      [super viewDidLoad];
  
      self.blueLayer = [CALayer layer];
      self.blueLayer.frame = CGRectMake(50, 50, 100, 100);
      self.blueLayer.backgroundColor = [UIColor blueColor].CGColor;
      [self.layerView.layer addSublayer:self.blueLayer];
      
  }
  - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
  
      //使用containsPoint方法
      CGPoint point = [[touches anyObject] locationInView:self.view];
      point = [self.layerView.layer convertPoint:point fromLayer:self.view.layer];
  
      if ([self.layerView.layer containsPoint:point]) {
          point = [self.blueLayer convertPoint:point fromLayer:self.layerView.layer];
  
          if ([self.blueLayer containsPoint:point]) {
              NSLog(@"蓝色");
          }else{
              NSLog(@"白色");
          }
      }else{
          NSLog(@"灰色");
      }
  }

hitTest

• 同样接收一个 CGPoint类型的参数,返回图层本身

- (void)viewDidLoad {
    [super viewDidLoad];

    self.blueLayer = [CALayer layer];
    self.blueLayer.frame = CGRectMake(50, 50, 100, 100);
    self.blueLayer.backgroundColor = [UIColor blueColor].CGColor;
    [self.layerView.layer addSublayer:self.blueLayer];
    
}
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{

    //使用hitTest方法
    CGPoint point = [[touches anyObject] locationInView:self.view];

    CALayer *layer = [self.layerView.layer hitTest:point];

    if (layer == self.blueLayer) {
        NSLog(@"蓝色");
    }else if(layer == self.layerView.layer){
        NSLog(@"白色");
    }else{
        NSLog(@"灰色");
    }
}