ios View拖拽

 1 // 当手指在view上移动的时候调用
 2 - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
 3 {
 4     
 5     UITouch *touch = [touches anyObject];
 6     // 0. 获取上一次的位置
 7     CGPoint prePoint = [touch previousLocationInView:self];
 8     
 9     // 1.获取当前的位置
10     CGPoint currentPoint = [touch locationInView:self];
11     
12     CGFloat moveX = currentPoint.x - prePoint.x;
13     CGFloat moveY = currentPoint.y - prePoint.y;
14     
15     // 2.改变当前视图的位置,为手指指定的位置
16     CGPoint temp =  self.center;
17     temp.x += moveX;
18     temp.y += moveY;
19     self.center = temp;
20 
21 }