iOS手势-UIGestureRecognizer

1. UIGestureRecognizer

  1. 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

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