让 View 可以移动

//添加事件

UIPanGestureRecognizer *pan_top = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(panTopView:)];

//处发事件方法

CGPoint point = [pan translationInView:self.view];
    CGPoint newPoint = CGPointMake(View.center.x + point.x, View.center.y + point.y);
    [vie_top setCenter:newPoint];
    [pan setTranslation:CGPointZero inView:self.view];