UIKit之触摸、响应者链

触摸

//如果想让UIView实现出触摸方法的话,咱们需要重写与touch有关的方法
- (void)touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event{
    NSLog(@"开始触摸");
   // 1. UITouch表示触摸屏幕的一根手指
    UITouch*touch = [touches anyObject];
   // 2.获取触摸屏幕时的坐标
    CGPointstartPoint = [touch locationInView:self];
   // 3.打印坐标
    NSLog(@"%@",NSStringFromCGPoint(startPoint))
}

- (void)touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event{
   NSLog(@"正在摸");
    self.backgroundColor= [UIColorcolorWithRed:arc4random()%256/256.0green:arc4random()%256/256.0blue:arc4random()%256/256.0alpha:1];
   UITouch*moveTouch = [touches anyObject];
   CGPointmovePoint = [moveTouch locationInView:self];
   NSLog(@"%@",NSStringFromCGPoint(movePoint));
}
- (void)touchesCancelled:(NSSet*)touches withEvent:(UIEvent*)event{
   NSLog(@"不摸了");
}
- (void)touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event{
   NSLog(@"摸完了");
}

响应者链

//响应者链多个响应者组成的链
//首先执行检测过程,信息先从UIApplication->Appdelegate->UIWindow->Controller->UIView->其子类(确认在哪个视图上)

//响应过程
//先从View的子类里面寻找有没有事件实现的方法,如果有,事件执行,响应者链完后,如果没有就一层一层往上找,最后找到UIApplication,如果再没有就丢弃