/*  定義屬性 */@interface ViewController (){  CGPoint _startPoint; //開始點擊的點  CGPoint _endPoint; //結束點擊的點    UILabel *_label1; //顯示當前觸摸的狀態的標簽  UILabel *_label2;  UILabel *_label3;  UILabel *_label4;  UIImageView *_imageView; //笑臉圖片}/*  觸摸事件UITouch的系列方法如下所示 <一>到<四> */#pragma mark <一> 當一個或多個手指觸碰屏幕時，發送touchesBegan:withEvent:消息-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{  _label1.text = @"觸摸 開始 ";    //1. 首先獲取觸摸屏幕的手指  UITouch * touch = [touches anyObject];    //2. 點擊的當前點的坐標  CGPoint point = [touch locationInView:self.view];  _label2.text = [NSString stringWithFormat:@"當前點得坐標:x=%.1f, y=%.1f",point.x,point.y];    //4. 獲取觸摸屏幕的次數  int tapCount = touch.tapCount;  //5. 獲取觸摸屏幕的手指根數  int fingerCount = touches.count;    _label3.text = [NSString stringWithFormat:@"觸摸屏幕次數為%i, 觸摸的手指數為%i",tapCount,fingerCount];    //6. 當前視圖默認只支持單點觸摸 如果想添加多點觸摸 必須開啟多點觸摸模式  self.view.multipleTouchEnabled = YES;    //7.1. 得到開始點擊的點,得到最后點擊的點，計算一下，看看做了什么操作  _startPoint = [touch locationInView:self.view];  _label4.text = @"";}#pragma mark <二> 當一個或多個手指在屏幕上移動時，發送touchesMoved:withEvent:消息-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{  _label1.text = @"觸摸 move...";  CGPoint point = [[touches anyObject] locationInView:self.view];  _label2.text = [NSString stringWithFormat:@"當前點得坐標:x=%.1f, y=%.1f",point.x,point.y];}#pragma mark <三> 當一個或多個手指離開屏幕時，發送touchesEnded:withEvent:消息-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{  _label1.text = @"觸摸 結束";  CGPoint point = [[touches anyObject] locationInView:self.view];    //3. 判斷是否進入了圖片范圍內  if (CGRectContainsPoint(_imageView.frame, point)) {    _label2.text = @"停留在笑臉圖片范圍內";  }  else  {    _label2.text = @"停留在笑臉圖片外面";  }    //7.2 計算開始到結束偏移量  float distanceX = fabsf(point.x - _startPoint.x);  //獲取手指縱向移動的偏移量  float distanceY = fabsf(point.y - _startPoint.y);    _label4.text = [NSString stringWithFormat:@"x偏移了%.1f，y方向偏移了%.1f",distanceX,distanceY];    _startPoint = CGPointZero;}#pragma mark <四> 當觸摸序列被諸如電話呼入這樣的系統事件打斷所意外取消時，發送touchesCancelled:withEvent:消息-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event{  _label1.text = @"觸摸 取消";}