UITouch的用法

UITouch一般无法直接获取，是通过UIView的touchesBegan等函数获得。

//这四个方法是UIResponder中得方法

// Generally, all responders which do custom touch handling should override all four of these methods.

// Your responder will receive either touchesEnded:withEvent: or touchesCancelled:withEvent: for each

// touch it is handling (those touches it received in touchesBegan:withEvent:).

// *** You must handle cancelled touches to ensure correct behavior in your application.  Failure to

// do so is very likely to lead to incorrect behavior or crashes.

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event;

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event;

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event;

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event;

 

前面写了几次提到UITouch，也提到了UITouch的三个代理方法

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event;

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event;

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event;

这里还有几个代理方法

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event;//触摸取消事件

- (void)remoteControlReceivedWithEvent:(UIEvent *)event;//注册接受触摸事件的Control

下面写了一个简单的DEMO，触摸时，移动图片

- (void)loadView {

[super loadView];

// Release any retained subviews of the main view.

// e.g. self.myOutlet = nil;

UIImageView *image = [[UIImageView alloc] initWithFrame:CGRectMake(20.0, 50.0, 45.0, 45.0)];

image.image = [UIImage imageNamed:@"1.png"];

image.tag = 100;

[self.view addSubview:image];

}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event

{

UITouch *touch = [touches anyObject];

UIImageView *view1 = (UIImageView*)[self.view  viewWithTag:100];

CGPoint point = [touch  locationInView:self.view];

CGRect  frame = view1.frame;

frame.origin = point;

view1.frame = frame;

}

效果