iOS手势-UIPanGestureRecognizer

UIPanGestureRecognizer是iOS开发中不怎么常用的一个拖动手势.

打开UIPanGestureRecognizer.h

 // default is 1. the minimum number of touches required to match

// 识别拖动手势需要的最少的手指数,少于这个数目无法识别

@property (nonatomic)          NSUInteger minimumNumberOfTouches __TVOS_PROHIBITED; 

 // default is UINT_MAX. the maximum number of touches that can be down;

//识别拖动手势限制的最大的手指数,超过这个数目无法识别

@property (nonatomic)          NSUInteger maximumNumberOfTouches __TVOS_PROHIBITED; 

 // translation in the coordinate system of the specified view

// 获取到的是移动后手指在相对坐标系内移动的距离

- (CGPoint)translationInView:(nullable UIView *)view;                       

//一般在Action内计算偏移量的时候,使用该方法将偏移量置位0(偏移量是一直累加的,不会自动清零)

- (void)setTranslation:(CGPoint)translation inView:(nullable UIView *)view;

 // velocity of the pan in points/second in the coordinate system of the specified view

// 这个可以获取在View中的手势的平移速度

- (CGPoint)velocityInView:(nullable UIView *)view;