iOS - UITouch

前言

	NS_CLASS_AVAILABLE_IOS(2_0)  @interface UITouch : NSObject
	@available(iOS 2.0, *)		 public class UITouch : NSObject

• 触摸事件基本都是发生在 viewController 中，首先触摸的对象是视图，而视图的类 UIView 继承了 UIRespnder 类，但是要对事件作出处理，还需要重写 UIResponder 类中定义的事件处理函数。根据不同的触摸状态，程序会调用相应的处理函数。

1、touch 的创建

• 在系统触摸事件处理方法中实现

• Objective-C

  	// 获取任意一个触摸对象
   	UITouch *touch = [touches anyObject];
  
  	// 获取任意一个触摸对象
  	UITouch *touch = [[event allTouches] anyObject];
  
  	// 获取指定的 view 触摸对象
  	UITouch *touch = [[event touchesForView:myView] anyObject];
  
  	// 获取指定的 window 触摸对象
  	UITouch *touch = [[event touchesForWindow:self.view.window] anyObject];
  

• Swift

  	// 获取任意一个触摸对象
  	let touch:UITouch = touches.first! as UITouch
  
  	// 获取任意一个触摸对象
  	let touch2:UITouch = (event?.allTouches()?.first!)! as UITouch
  
  	// 获取指定的 view 触摸对象
  	let touch3:UITouch = (event!.touchesForView(myView!)?.first)! as UITouch
  
  	// 获取指定的 window 触摸对象
  	let touch4:UITouch = (event!.touchesForWindow(self.view.window!)?.first)! as UITouch
  

2、touch 的设置

• 在系统触摸事件处理方法中实现

• Objective-C

  	// 设置接收多点触摸
  	/*
  		默认为 NO，即视图默认不接收多点触摸
  	*/
  	self.view.multipleTouchEnabled = YES;
  

• Swift

  	// 设置接收多点触摸
  	/*
  		默认为 NO，即视图默认不接收多点触摸
  	*/
  	self.view.multipleTouchEnabled = true
  

3、touch 的获取

• 在系统触摸事件处理方法中实现

• Objective-C

  	// 获取触摸窗口
  	UIWindow *touchWindow = touch.window;
  
  	// 获取触摸视图
  	UIView *touchView = touch.view;
  
  	// 获取触摸手势
  	NSArray *touchGesture = touch.gestureRecognizers;
  
  	// 获取触摸次数
  	NSUInteger tapCount = touch.tapCount;
  
  	// 获取触摸时间
  	NSTimeInterval timestamp = touch.timestamp;
  
  	// 获取触摸状态
  	/*
  		UITouchPhaseBegan,    	   // whenever a finger touches the surface.     触摸开始
  		UITouchPhaseMoved,    	   // whenever a finger moves on the surface.    接触点移动
  		UITouchPhaseStationary,    // whenever a finger is touching the surface but hasn't moved
  		                           // since the previous event.                  接触点无移动
  		UITouchPhaseEnded,    	   // whenever a finger leaves the surface.      触摸结束
  		UITouchPhaseCancelled,     // whenever a touch doesn't end but we need to stop tracking
  		                           // (e.g. putting device to face)              触摸取消
  	*/
  	UITouchPhase touchPhase = touch.phase;
  
  	// 获取触摸位置
  
  		// 上次触摸点的位置
  		CGPoint lastPoint = [touch previousLocationInView:self.view];
  
  		// 当前触摸点的位置
  		CGPoint currentPoint = [touch locationInView:self.view];
  
  	// 获取触摸半径
  	CGFloat majorRadius = touch.majorRadius;
  	CGFloat majorRadiusTolerance = touch.majorRadiusTolerance;
  

• Swift

  	// 获取触摸窗口
  	let touchWindow:UIWindow = touch.window!
  
  	// 获取触摸视图
  	let touchView:UIView = touch.view!
  
  	// 获取触摸手势
  	let touchGesture:[AnyObject] = touch.gestureRecognizers!
  
  	// 获取触摸次数
  	let tapCount:Int = touch.tapCount
  
  	// 获取触摸时间
  	let timestamp:NSTimeInterval = touch.timestamp
  
  	// 获取触摸状态
  	/*
  		case Began,        // whenever a finger touches the surface.     触摸开始
  		case Moved,        // whenever a finger moves on the surface.    接触点移动
  		case Stationary,   // whenever a finger is touching the surface but hasn't moved since
  		                   // the previous event.                        接触点无移动
  		case Ended,        // whenever a finger leaves the surface.      触摸结束
  		case Cancelled,    // whenever a touch doesn't end but we need to stop tracking
  		                   // (e.g. putting device to face)              触摸取消
  	*/
  	let touchPhase:UITouchPhase = touch.phase
  
  	// 获取触摸位置
  
  		// 上次触摸点的位置
      	let lastPoint:CGPoint = touch.previousLocationInView(self.view)
  
  		// 当前触摸点的位置
      	let currentPoint:CGPoint = touch.locationInView(self.view)
  
  	// 获取触摸半径
  	let majorRadius:CGFloat = touch.majorRadius
   	let majorRadiusTolerance:CGFloat = touch.majorRadiusTolerance
  

4、系统触摸事件处理方法

• 不用手动调用

• Objective-C

  	// 触摸开始，重写 UIResponder 中定义的方法
  	- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
  
  	}
  
  	// 触摸移动，重写 UIResponder 中定义的方法
  	- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
  
  	}
  
  	// 触摸结束，重写 UIResponder 中定义的方法
  	- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
  
  	}
  
  	// 触摸取消，重写 UIResponder 中定义的方法
  	- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
  
  	}
  

• Swift

  	// 触摸开始，重写 UIResponder 中定义的方法
  	override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
  
  	}
  
  	// 触摸移动，重写 UIResponder 中定义的方法
  	override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
  
  	}
  
  	// 触摸结束，重写 UIResponder 中定义的方法
  	override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
  
  	}
  
  	// 触摸取消，重写 UIResponder 中定义的方法
  	override func touchesCancelled(touches: Set<UITouch>!, withEvent event: UIEvent!) {
  
  	}
  

5、视图随触摸移动

• Objective-C

  	// 触摸移动
  	- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
  
      	// 获取触摸对象
      	UITouch *touch = [touches anyObject];
      	UIView *tapView = touch.view;
  
      	// 获取触摸点位置
      	CGPoint lastPoint = [touch previousLocationInView:self.view];
      	CGPoint currentPoint = [touch locationInView:self.view];
  
      	// 改变视图中心坐标
      	CGPoint tapViewCenter = tapView.center;
  
      	tapViewCenter.x += currentPoint.x - lastPoint.x;
      	tapViewCenter.y += currentPoint.y - lastPoint.y;
  
      	tapView.center = tapViewCenter;
  	}
  

• Swift

  	// 触摸移动
  	override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
  
      	// 获取触摸对象
      	let touch:UITouch = touches.first! as UITouch
      	let tapView = touch.view
  
      	// 获取触摸点位置
      	let lastPoint:CGPoint = touch.previousLocationInView(self.view)
      	let currentPoint:CGPoint = touch.locationInView(self.view)
  
      	// 改变视图中心坐标
      	var tapViewCenter = tapView!.center
  
      	tapViewCenter.x += currentPoint.x - lastPoint.x
      	tapViewCenter.y += currentPoint.y - lastPoint.y
  
      	tapView!.center = tapViewCenter
  	}
  

6、单击／双击触摸

• Objective-C

  	// 触摸结束
  	- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
  
      	UITouch *touch = [touches anyObject];
  
      	// 单击
      	if (touch.tapCount == 1) {
  
  			 // 响应单击触摸事件
          	[self performSelector:@selector(singleTapClick) withObject:nil afterDelay:0];
      	}
      	// 双击
      	else if (touch.tapCount == 2) {
  
  			// 取消单击触摸响应事件
          	[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(singleTapClick) object:nil];
  
  			// 响应双击触摸事件
          	[self performSelector:@selector(doubleTapClick) withObject:nil afterDelay:0];
      	}
  	}
  
  	// 单击触摸响应事件处理
  	- (void)singleTapClick {
  
      	self.view.backgroundColor = [UIColor greenColor];
  	}
  
  	// 双击触摸响应事件处理
  	- (void)doubleTapClick {
  
      	self.view.backgroundColor = [UIColor orangeColor];
  	}
  

• Swift

  	// 触摸结束
  	override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
  
  		let touch = touches.first! as UITouch
  
  		// 单击
      	if touch.tapCount == 1 {
  
  			// 响应单击触摸事件
         	self.performSelector(#selector(singleTapClick), withObject: nil, afterDelay: 0)
      	}
  
      	// 双击
      	if touch.tapCount == 2 {
  
          	// 取消单击触摸响应事件
          	NSObject.cancelPreviousPerformRequestsWithTarget(self, selector: #selector(singleTapClick), object: nil)
  
          	// 响应双击触摸事件
          	self.performSelector(#selector(doubleTapClick), withObject: nil, afterDelay: 0)
      	}
  	}
  
  	// 单击触摸响应事件处理
  	func singleTapClick() {
  
      	self.view.backgroundColor = UIColor.greenColor()
  	}
  
  	// 双击触摸响应事件处理
  	func doubleTapClick() {
  
      	self.view.backgroundColor = UIColor.orangeColor()
  	}