你的位置:首页 > 操作系统

[操作系统]你真的了解UIGestureRecognizer吗?


一:首先查看一下关于UIGestureRecognizer的定义

//当前手势状态typedef NS_ENUM(NSInteger, UIGestureRecognizerState) {  //尚未识别是何种手势操作(但可能已经触发了触摸事件),默认状态  UIGestureRecognizerStatePossible,    //手势已经开始,此时已经被识别,但是这个过程中可能发生变化,手势操作尚未完成  UIGestureRecognizerStateBegan,     //手势状态发生改变  UIGestureRecognizerStateChanged,   // 手势识别操作完成(此时已经松开手指)   UIGestureRecognizerStateEnded,   //手势被取消,恢复到默认状态    UIGestureRecognizerStateCancelled,   //手势识别失败,恢复到默认状态  UIGestureRecognizerStateFailed,    //手势识别完成,同end  UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded };NS_CLASS_AVAILABLE_IOS(3_2) @interface UIGestureRecognizer : NSObject//创建一个手势对象并添加触发事件- (instancetype)initWithTarget:(nullable id)target action:(nullable SEL)action NS_DESIGNATED_INITIALIZER; //给一个手势对象添加监听事件- (void)addTarget:(id)target action:(SEL)action;  //移除一个手势的监听事件- (void)removeTarget:(nullable id)target action:(nullable SEL)action; //获取当前手势状态@property(nonatomic,readonly) UIGestureRecognizerState state; //委托@property(nullable,nonatomic,weak) id <UIGestureRecognizerDelegate> delegate; //手势识别是否可用@property(nonatomic, getter=isEnabled) BOOL enabled; //获取手势触摸的View视图 只读@property(nullable, nonatomic,readonly) UIView *view;     //是否取消触摸控件的响应默认为YES,这种情况下当手势识别器识别到触摸之后,会发送touchesCancelled给触摸到的控件以取消控件view对touch的响应,这个时候只有手势识别器响应touch,当设置成NO时,手势识别器识别到触摸之后不会发送touchesCancelled给控件,这个时候手势识别器和控件view均响应touch。注意:手势识别和触摸事件是同时存在的,只是因为touchesCancelled导致触摸事件失效、@property(nonatomic) BOOL cancelsTouchesInView;    //是否延迟发送触摸事件给触摸到的控件默认是NO,这种情况下当发生一个触摸时,手势识别器先捕捉到到触摸,然后发给触摸到的控件,两者各自做出响应。如果设置为YES,手势识别器在识别的过程中(注意是识别过程),不会将触摸发给触摸到的控件,即控件不会有任何触摸事件。只有在识别失败之后才会将触摸事件发给触摸到的控件,这种情况下控件view的响应会延迟约0.15ms。@property(nonatomic) BOOL delaysTouchesBegan;    //如果触摸识别失败是否立即结束本次手势识别的触摸事件@property(nonatomic) BOOL delaysTouchesEnded;    //指定一个手势需要另一个手势执行失败才会执行,同时触发多个手势使用其中一个手势的解决办法有时手势是相关联的,如单机和双击,点击和长按,点下去瞬间可能只会识别到单击无法识别其他,该方法可以指定某一个 手势,即便自己已经满足条件了,也不会立刻触发,会等到该指定的手势确定失败之后才触发- (void)requireGestureRecognizerToFail:(UIGestureRecognizer *)otherGestureRecognizer;//获取当前触摸在指定视图上的点- (CGPoint)locationInView:(nullable UIView*)view;                //获取触摸手指数- (NSUInteger)numberOfTouches;                     //多指触摸的触摸点相对于指定视图的位置- (CGPoint)locationOfTouch:(NSUInteger)touchIndex inView:(nullable UIView*)view; @end

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

知识点1:关于UIGestureRecognizer的子类如下(下面这些才是我们平常会直接运用到的类):

UITapGestureRecognizer(轻触,点按)UILongPressGestureRecognizer(长按)UISwipeGestureRecognizer(轻扫手势)UIRotationGestureRecognizer(旋转手势)UIPanGestureRecognizer(拖拽手势)UIPinchGestureRecognizer(捏合手势,缩放用)

实例如下:

//拖拽手势UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];[tagButton addGestureRecognizer:pan];- (void)pan:(UIPanGestureRecognizer *)pan{       }

//给视图增加点击动作UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapHandle:)];[self.view addGestureRecognizer:tap];-(void)tapHandle:(UITapGestureRecognizer*)tap{  }

二:关于UIGestureRecognizerDelegate代理的内容

@protocol UIGestureRecognizerDelegate <NSObject>@optional//开始进行手势识别时调用的方法,返回NO则结束识别,不再触发手势,用处:可以在控件指定的位置使用手势识别- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer;//是否支持多手势触发,返回YES,则可以多个手势一起触发方法,返回NO则为互斥是否允许多个手势识别器共同识别,一个控件的手势识别后是否阻断手势识别继续向下传播,默认返回NO;如果为YES,响应者链上层对象触发手势识别后,如果下层对象也添加了手势并成功识别也会继续执行,否则上层对象识别后则不再继续传播- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer;// 这个方法返回YES,第一个手势和第二个互斥时,第一个会失效- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRequireFailureOfGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer NS_AVAILABLE_IOS(7_0);//这个方法返回YES,第一个和第二个互斥时,第二个会失效- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldBeRequiredToFailByGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer NS_AVAILABLE_IOS(7_0);//手指触摸屏幕后回调的方法,返回NO则不再进行手势识别,方法触发等此方法在window对象在有触摸事件发生时,调用gesture recognizer的touchesBegan:withEvent:方法之前调用,如果返回NO,则gesture recognizer不会看到此触摸事件。(默认情况下为YES)- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch;@end

知识点1:

//是否同时支持多种手势- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{ return YES;}//是否允许开始点击- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer{return YES;}//设置点击的范围- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{//获取当前的触摸点 CGPoint curp = [touch locationInView:self.imageView]; if (curp.x <= self.imageView.bounds.size.width*0.5) {   return NO; }else{   return YES; }}

知识点2:UITapGestureRecognizer和UIButton的点击事件冲突的解决办法

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{  if ([touch.view isKindOfClass:[UIButton class]])  {    return NO;  }     return YES;}

三:关于UIGestureRecognizer的子类知识

1:UITapGestureRecognizer(轻触,点按)

NS_CLASS_AVAILABLE_IOS(3_2) @interface UITapGestureRecognizer : UIGestureRecognizer//设置能识别到手势的最少的轻触次数(默认为1)@property (nonatomic) NSUInteger numberOfTapsRequired;   //设置能识别到手势的最少的手指的个数(默认为1) @property (nonatomic) NSUInteger numberOfTouchesRequired; @end

知识点1:实例代码如下

// 创建一个手势对象UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapAction:)];// 设置能识别到手势的最少的轻触次数tap.numberOfTapsRequired = 3;// 设置能识别到手势的最少的手指的个数tap.numberOfTouchesRequired = 2;//把手势对象添加到对应的控件中[self.imgView addGestureRecognizer:tap];

2:UILongPressGestureRecognizer(长按手势)

NS_CLASS_AVAILABLE_IOS(3_2) @interface UILongPressGestureRecognizer : UIGestureRecognizer//设置能识别到手势的最少的轻触次数(默认为1)@property (nonatomic) NSUInteger numberOfTapsRequired;   //设置能识别到手势的最少的手指的个数(默认为1) @property (nonatomic) NSUInteger numberOfTouchesRequired;  //设置能识别到长按手势的最短的长按时间,单位:秒,默认为0.5@property (nonatomic) CFTimeInterval minimumPressDuration; //设置长按时允许移动的最大距离,单位:像素,默认为10像素@property (nonatomic) CGFloat allowableMovement;      @end

知识点1:实例代码如下

UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressAction:)];// 设置能识别到长按手势的最小的长按时间longPress.minimumPressDuration = 0.5;// "容错的范围"longPress.allowableMovement = 10;// 把长按手势添加到对应的控件中[self.imgView addGestureRecognizer:longPress];

3:UISwipeGestureRecognizer(轻扫手势)

typedef NS_OPTIONS(NSUInteger, UISwipeGestureRecognizerDirection) {  UISwipeGestureRecognizerDirectionRight = 1 << 0, //向右滑  UISwipeGestureRecognizerDirectionLeft = 1 << 1, //向左滑  UISwipeGestureRecognizerDirectionUp  = 1 << 2, //向上滑  UISwipeGestureRecognizerDirectionDown = 1 << 3 //向下滑};NS_CLASS_AVAILABLE_IOS(3_2) @interface UISwipeGestureRecognizer : UIGestureRecognizer //最少触摸手指个数,默认为1@property(nonatomic) NSUInteger            numberOfTouchesRequired; //设置轻扫手势支持的方向,默认为向右滑@property(nonatomic) UISwipeGestureRecognizerDirection direction;        @end

知识点1:实例代码如下

UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeAction:)];swipeLeft.direction = UISwipeGestureRecognizerDirectionLeft;[self.imgView addGestureRecognizer:swipeLeft];

4:UIRotationGestureRecognizer(旋转手势)

NS_CLASS_AVAILABLE_IOS(3_2) @interface UIRotationGestureRecognizer : UIGestureRecognizer//旋转的角度@property (nonatomic)     CGFloat rotation; //旋转速度,单位:度/秒、     @property (nonatomic,readonly) CGFloat velocity;      @end

知识点1:实例代码如下

//为图片框添加一个旋转手势UIRotationGestureRecognizer *rotation = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotateAction:)];rotation.delegate = self;[self.imgView addGestureRecognizer:rotation];// 旋转手势的监听方法- (void)rotateAction:(UIRotationGestureRecognizer *)recognizer {// 在原来的基础上, 累加多少度recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation);// 每次旋转完毕后将rotation的值, 恢复到0的位置.recognizer.rotation = 0;}

5:UIPanGestureRecognizer(拖拽手势)

NS_CLASS_AVAILABLE_IOS(3_2) @interface UIPanGestureRecognizer : UIGestureRecognizer //设置触发拖拽最少手指数,默认为1@property (nonatomic)     NSUInteger minimumNumberOfTouches;  //设置触发拖拽最多手指数,默认为 UINT_MAX 无限大@property (nonatomic)     NSUInteger maximumNumberOfTouches;  //获取当前拖拽位置- (CGPoint)translationInView:(nullable UIView *)view;            //设置当前拖拽位置- (void)setTranslation:(CGPoint)translation inView:(nullable UIView *)view;//设置拖拽速度,单位:像素/秒- (CGPoint)velocityInView:(nullable UIView *)view;             @end

知识点1:实例代码

UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panAction:)];[self.imgView addGestureRecognizer:pan];// 拖拽手势的监听方法- (void)panAction:(UIPanGestureRecognizer *)recognizer {// 1. 获取手指拖拽的时候, 平移的值CGPoint translation = [recognizer translationInView:recognizer.view];// 2. 让当前控件做响应的平移recognizer.view.transform = CGAffineTransformTranslate(recognizer.view.transform, translation.x, translation.y);// 3. 每次平移手势识别完毕后, 让平移的值不要累加[recognizer setTranslation:CGPointZero inView:recognizer.view];}

6:UIPinchGestureRecognizer(捏合手势,缩放用)

NS_CLASS_AVAILABLE_IOS(3_2) @interface UIPinchGestureRecognizer : UIGestureRecognizer //设置缩放比例@property (nonatomic)     CGFloat scale;   //获取捏合速度,单位:缩放比/秒     @property (nonatomic,readonly) CGFloat velocity;      @end

知识点1:实例代码

UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchAction:)];pinch.delegate = self;[self.imgView addGestureRecognizer:pinch];// 捏合手势监听方法- (void)pinchAction:(UIPinchGestureRecognizer *)recognizer {recognizer.view.transform = CGAffineTransformScale(recognizer.view.transform, recognizer.scale, recognizer.scale);recognizer.scale = 1.0;}