iOS手势-UIGestureRecognizer

原文链接

1. UIGestureRecognizer

父类是NSObject利用手势识别器---UIGestureRecognizer，能轻松识别用户在某个view上面做的一些常见手势UIGestureRecognizer是一个抽象类，定义了所有手势的基本行为，使用它的子类才能处理具体的手势，详见其子类介绍一个手势只能支持一个方向默认只支持一个手势，若要实现多个手势，需要设置手势代理，遵守<UIGestureRecognizerDelegate>，并实现shouldRecognizeSimultaneouslyWithGestureRecognizer，返回YES。

2. 手势识别的状态

手势状态含义UIGestureRecognizerStatePossible没有触摸事件发生，所有手势识别的默认状态UIGestureRecognizerStateBegan一个手势已经开始但尚未改变或者完成时UIGestureRecognizerStateChanged手势状态改变UIGestureRecognizerStateEnded手势完成UIGestureRecognizerStateCancelled手势取消，恢复至Possible状态UIGestureRecognizerStateFailed手势失败，恢复至Possible状态UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded识别到手势识别

3. UIGestureRecognizer属性

// 手势状态 @property(nonatomic,readonly) UIGestureRecognizerState state;

//手势代理 @property(nullable,nonatomic,weak) id <UIGestureRecognizerDelegate> delegate;

// 手势是否可用（默认可用） // 当前在识别手势时不能修改手势是否可用 @property(nonatomic, getter=isEnabled) BOOL enabled;

// 手势的视图 @property(nullable, nonatomic,readonly) UIView *view;

@property(nonatomic) BOOL cancelsTouchesInView; @property(nonatomic) BOOL delaysTouchesBegan; @property(nonatomic) BOOL delaysTouchesEnded;

@property(nonatomic, copy) NSArray<NSNumber *> *allowedTouchTypes @property(nonatomic, copy) NSArray<NSNumber *> *allowedPressTypes

4. UIGestureRecognizer方法

// 初始化手势，直接用initWithTarget就好，另外两个忽略 // -(void)handleGesture; // -(void)handleGesture:(UIGestureRecognizer*)gestureRecognizer; - (instancetype)initWithTarget:(nullable id)target action:(nullable SEL)action

// 增加监听和移除监听

(void)addTarget:(id)target action:(SEL)action;(void)removeTarget:(nullable id)target action:(nullable SEL)action; //target为nil，则移除所有相同方法名的方法

// 获取touch的位置

(CGPoint)locationInView:(nullable UIView*)view;

// 获取locations中的touches的数量

(NSUInteger)numberOfTouches;

// 获取特定角标的touch的位置

(CGPoint)locationOfTouch:(NSUInteger)touchIndex inView:(nullable UIView*)view;

(void)requireGestureRecognizerToFail:(UIGestureRecognizer *)otherGestureRecognizer; @end

5. UIGestureRecognizer的代理--UIGestureRecognizerDelegate

// 是否允许触发当前手势 - (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer;

// Simultaneously:同时 sɪml’teɪnɪəslɪ // 是否允许同时支持多个手势

(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer;

// 是否接收触摸手势

(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch;

// 是否接收按压手势

(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceivePress:(UIPress *)press;

(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRequireFailureOfGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer NS_AVAILABLE_IOS(7_0);

(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldBeRequiredToFailByGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer NS_AVAILABLE_IOS(7_0);

@end

6. UIGestureRecognizer的子类

6.1. 点按手势

6.2. 捏合手势——用于缩放

6.3. 拖动手势

6.4. 轻扫手势

6.5. 旋转手势

6.6. 长按手势