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[操作系统]iOS 手势操作:拖动、捏合、旋转、点按、长按、轻扫、自定义

1、UIGestureRecognizer 介绍

手势识别在 iOS 中非常重要,他极大地提高了移动设备的使用便捷性。

iOS 系统在 3.2 以后,他提供了一些常用的手势(UIGestureRecognizer 的子类),开发者可以直接使用他们进行手势操作。

  • UIPanGestureRecognizer(拖动)

  • UIPinchGestureRecognizer(捏合)

  • UIRotationGestureRecognizer(旋转)

  • UITapGestureRecognizer(点按)

  • UILongPressGestureRecognizer(长按)

  • ​UISwipeGestureRecognizer(轻扫)

另外,可以通过继承 UIGestureRecognizer 类,实现自定义手势(手势识别器类)。

PS:自定义手势时,需要 #import <UIKit/UIGestureRecognizerSubclass.h>,一般需实现如下方法:

1 - (void)reset;2 3 - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event;4 - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event;5 - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event;6 - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event;7 //以上方法在分类 UIGestureRecognizer (UIGestureRecognizerProtected) 中声明,更多方法声明请自行查看

UIGestureRecognizer 的继承关系如下:

 

2、手势状态

在六种手势识别中,只有一种手势是离散型手势,他就是 UITapGestureRecognizer。

离散型手势的特点就是:一旦识别就无法取消,而且只会调用一次手势操作事件(初始化手势时指定的回调方法)。

​换句话说其他五种手势是连续型手势,而连续型手势的特点就是:会多次调用手势操作事件,而且在连续手势识别后可以取消手势。从下图可以看出两者调用操作事件的次数是不同的:

手势状态枚举如下:

1 typedef NS_ENUM(NSInteger, UIGestureRecognizerState) {2   UIGestureRecognizerStatePossible,  // 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3   UIGestureRecognizerStateBegan,   // 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4   UIGestureRecognizerStateChanged,  // 手势状态发生转变5   UIGestureRecognizerStateEnded,   // 手势识别操作完成(此时已经松开手指)6   UIGestureRecognizerStateCancelled, // 手势被取消,恢复到默认状态7   UIGestureRecognizerStateFailed,   // 手势识别失败,恢复到默认状态8   UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded // 手势识别完成,同UIGestureRecognizerStateEnded9 };

  • 对于离散型手势 UITapGestureRecgnizer 要么被识别,要么失败,点按(假设点按次数设置为1,并且没有添加长按手势)下去一次不松开则此时什么也不会发生,松开手指立即识别并调用操作事件,并且状态为3(已完成)。
  • 但是连续型手势要复杂一些,就拿旋转手势来说,如果两个手指点下去不做任何操作,此时并不能识别手势(因为我们还没旋转)但是其实已经触发了触摸开始事件,此时处于状态0;如果此时旋转会被识别,也就会调用对应的操作事件,同时状态变成1(手势开始),但是状态1只有一瞬间;紧接着状态变为2(因为我们的旋转需要持续一会),并且重复调用操作事件(如果在事件中打印状态会重复打印2);松开手指,此时状态变为3,并调用1次操作事件。

 

3、使用手势的步骤

使用手势很简单,分为三步:

  1. 创建手势识别器对象实例。创建时,指定一个回调方法,当手势开始,改变、或结束时,执行回调方法。

  2. 设置手势识别器对象实例的相关属性(可选部分)

  3. 添加到需要识别的 View 中。每个手势只对应一个 View,当屏幕触摸在 View 的边界内时,如果手势和预定的一样,那就会执行回调方法。

PS:一个手势只能对应一个 View,但是一个 View 可以有多个手势。建议在真机上测试这些手势,模拟器操作不太方便,可能导致认为手势失效的情况。(模拟器测试捏合和旋转手势时,按住 option 键,再用触摸板或鼠标操作)

 

4、举例说明 

功能说明:

附加到两个图片视图 UIImageView 的有『拖动』、『捏合』、『旋转』、『点按』;

而『轻扫』和『自定义手势 KMGestureRecognizer』附加在根视图 UIView 中。

  1. 拖动:进行当前图片视图位置移动

  2. 捏合:进行当前图片视图缩放

  3. 旋转:进行当前图片视图角度旋转

  4. 点按:双击恢复当前图片视图的缩放、角度旋转、不透明度

  5. 长按:设置当前图片视图的不透明度为0.7

  6. 轻扫:左右轻扫设置两个图片视图为居中,同时以垂直居中的特定偏移量定位

  7. 自定义手势:挠痒功能,左右扫动共3次或以上,设置两个图片视图为居中,同时以水平居中的特定偏移量定位

 

效果如下:

KMGestureRecognizer.h

 1 #import <UIKit/UIKit.h> 2  3 typedef NS_ENUM(NSUInteger, Direction) { 4   DirectionUnknown, 5   DirectionLeft, 6   DirectionRight 7 }; 8  9 @interface KMGestureRecognizer : UIGestureRecognizer10 @property (assign, nonatomic) NSUInteger tickleCount; //挠痒次数11 @property (assign, nonatomic) CGPoint currentTickleStart; //当前挠痒开始坐标位置12 @property (assign, nonatomic) Direction lastDirection; //最后一次挠痒方向13 14 @end

KMGestureRecognizer.m

 1 #import "KMGestureRecognizer.h" 2 #import <UIKit/UIGestureRecognizerSubclass.h> 3  4 @implementation KMGestureRecognizer 5 #define kMinTickleSpacing 20.0 6 #define kMaxTickleCount 3 7  8 - (void)reset { 9   _tickleCount = 0;10   _currentTickleStart = CGPointZero;11   _lastDirection = DirectionUnknown;12   13   if (self.state == UIGestureRecognizerStatePossible) {14     self.state = UIGestureRecognizerStateFailed;15   }16 }17 18 - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {19   UITouch *touch = [touches anyObject];20   _currentTickleStart = [touch locationInView:self.view]; //设置当前挠痒开始坐标位置21 }22 23 - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {24   //『当前挠痒开始坐标位置』和『移动后坐标位置』进行 X 轴值比较,得到是向左还是向右移动25   UITouch *touch = [touches anyObject];26   CGPoint tickleEnd = [touch locationInView:self.view];27   CGFloat tickleSpacing = tickleEnd.x - _currentTickleStart.x;28   Direction currentDirection = tickleSpacing < 0 ? DirectionLeft : DirectionRight;29   30   //移动的 X 轴间距值是否符合要求,足够大31   if (ABS(tickleSpacing) >= kMinTickleSpacing) {32     //判断是否有三次不同方向的动作,如果有则手势结束,将执行回调方法33     if (_lastDirection == DirectionUnknown ||34       (_lastDirection == DirectionLeft && currentDirection == DirectionRight) ||35       (_lastDirection == DirectionRight && currentDirection == DirectionLeft)) {36       _tickleCount++;37       _currentTickleStart = tickleEnd;38       _lastDirection = currentDirection;39       40       if (_tickleCount >= kMaxTickleCount && self.state == UIGestureRecognizerStatePossible) {41         self.state = UIGestureRecognizerStateEnded;42         //NSLog(@"自定义手势成功,将执行回调方法");43       }44     }45   }46 }47 48 - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {49   [self reset];50 }51 52 - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {53   [self reset];54 }55 56 @end

ViewController.h

1 #import <UIKit/UIKit.h>2 #import "KMGestureRecognizer.h"3 4 @interface ViewController : UIViewController5 @property (strong, nonatomic) UIImageView *imgV;6 @property (strong, nonatomic) UIImageView *imgV2;7 @property (strong, nonatomic) KMGestureRecognizer *customGestureRecognizer;8 9 @end

ViewController.m

 1 #import "ViewController.h" 2  3 @interface ViewController () 4 - (void)handlePan:(UIPanGestureRecognizer *)recognizer; 5 - (void)handlePinch:(UIPinchGestureRecognizer *)recognizer; 6 - (void)handleRotation:(UIRotationGestureRecognizer *)recognizer; 7 - (void)handleTap:(UITapGestureRecognizer *)recognizer; 8 - (void)handleLongPress:(UILongPressGestureRecognizer *)recognizer; 9 - (void)handleSwipe:(UISwipeGestureRecognizer *)recognizer; 10 - (void)handleCustomGestureRecognizer:(KMGestureRecognizer *)recognizer; 11  12 - (void)bindPan:(UIImageView *)imgVCustom; 13 - (void)bindPinch:(UIImageView *)imgVCustom; 14 - (void)bindRotation:(UIImageView *)imgVCustom; 15 - (void)bindTap:(UIImageView *)imgVCustom; 16 - (void)bindLongPress:(UIImageView *)imgVCustom; 17 - (void)bindSwipe; 18 - (void)bingCustomGestureRecognizer; 19 - (void)layoutUI; 20 @end 21  22 @implementation ViewController 23  24 - (void)viewDidLoad { 25   [super viewDidLoad]; 26    27   [self layoutUI]; 28 } 29  30 - (void)didReceiveMemoryWarning { 31   [super didReceiveMemoryWarning]; 32   // Dispose of any resources that can be recreated. 33 } 34  35 #pragma mark - 处理手势操作 36 /** 37  * 处理拖动手势 38  * 39  * @param recognizer 拖动手势识别器对象实例 40 */ 41 - (void)handlePan:(UIPanGestureRecognizer *)recognizer { 42   //视图前置操作 43   [recognizer.view.superview bringSubviewToFront:recognizer.view]; 44    45   CGPoint center = recognizer.view.center; 46   CGFloat cornerRadius = recognizer.view.frame.size.width / 2; 47   CGPoint translation = [recognizer translationInView:self.view]; 48   //NSLog(@"%@", NSStringFromCGPoint(translation)); 49   recognizer.view.center = CGPointMake(center.x + translation.x, center.y + translation.y); 50   [recognizer setTranslation:CGPointZero inView:self.view]; 51    52   if (recognizer.state == UIGestureRecognizerStateEnded) { 53     //计算速度向量的长度,当他小于200时,滑行会很短 54     CGPoint velocity = [recognizer velocityInView:self.view]; 55     CGFloat magnitude = sqrtf((velocity.x * velocity.x) + (velocity.y * velocity.y)); 56     CGFloat slideMult = magnitude / 200; 57     //NSLog(@"magnitude: %f, slideMult: %f", magnitude, slideMult); //e.g. 397.973175, slideMult: 1.989866 58      59     //基于速度和速度因素计算一个终点 60     float slideFactor = 0.1 * slideMult; 61     CGPoint finalPoint = CGPointMake(center.x + (velocity.x * slideFactor), 62                     center.y + (velocity.y * slideFactor)); 63     //限制最小[cornerRadius]和最大边界值[self.view.bounds.size.width - cornerRadius],以免拖动出屏幕界限 64     finalPoint.x = MIN(MAX(finalPoint.x, cornerRadius), 65              self.view.bounds.size.width - cornerRadius); 66     finalPoint.y = MIN(MAX(finalPoint.y, cornerRadius), 67              self.view.bounds.size.height - cornerRadius); 68      69     //使用 UIView 动画使 view 滑行到终点 70     [UIView animateWithDuration:slideFactor*2 71                delay:0 72               options:UIViewAnimationOptionCurveEaseOut 73             animations:^{ 74               recognizer.view.center = finalPoint; 75              } 76              completion:nil]; 77   } 78 } 79  80 /** 81  * 处理捏合手势 82  * 83  * @param recognizer 捏合手势识别器对象实例 84 */ 85 - (void)handlePinch:(UIPinchGestureRecognizer *)recognizer { 86   CGFloat scale = recognizer.scale; 87   recognizer.view.transform = CGAffineTransformScale(recognizer.view.transform, scale, scale); //在已收缩大小基础下进行累加变化;区别于:使用 CGAffineTransformMakeScale 方法就是在原大小基础下进行变化 88   recognizer.scale = 1.0; 89 } 90  91 /** 92  * 处理旋转手势 93  * 94  * @param recognizer 旋转手势识别器对象实例 95 */ 96 - (void)handleRotation:(UIRotationGestureRecognizer *)recognizer { 97   recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation); 98   recognizer.rotation = 0.0; 99 }100 101 /**102  * 处理点按手势103  *104  * @param recognizer 点按手势识别器对象实例105 */106 - (void)handleTap:(UITapGestureRecognizer *)recognizer {107   UIView *view = recognizer.view;108   view.transform = CGAffineTransformMakeScale(1.0, 1.0);109   view.transform = CGAffineTransformMakeRotation(0.0);110   view.alpha = 1.0;111 }112 113 /**114  * 处理长按手势115  *116  * @param recognizer 点按手势识别器对象实例117 */118 - (void)handleLongPress:(UILongPressGestureRecognizer *)recognizer {119   //长按的时候,设置不透明度为0.7120   recognizer.view.alpha = 0.7;121 }122 123 /**124  * 处理轻扫手势125  *126  * @param recognizer 轻扫手势识别器对象实例127 */128 - (void)handleSwipe:(UISwipeGestureRecognizer *)recognizer {129   //代码块方式封装操作方法130   void (^positionOperation)() = ^() {131     CGPoint newPoint = recognizer.view.center;132     newPoint.y -= 20.0;133     _imgV.center = newPoint;134     135     newPoint.y += 40.0;136     _imgV2.center = newPoint;137   };138   139   //根据轻扫方向,进行不同控制140   switch (recognizer.direction) {141     case UISwipeGestureRecognizerDirectionRight: {142       positionOperation();143       break;144     }145     case UISwipeGestureRecognizerDirectionLeft: {146       positionOperation();147       break;148     }149     case UISwipeGestureRecognizerDirectionUp: {150       break;151     }152     case UISwipeGestureRecognizerDirectionDown: {153       break;154     }155   }156 }157 158 /**159  * 处理自定义手势160  *161  * @param recognizer 自定义手势识别器对象实例162 */163 - (void)handleCustomGestureRecognizer:(KMGestureRecognizer *)recognizer {164   //代码块方式封装操作方法165   void (^positionOperation)() = ^() {166     CGPoint newPoint = recognizer.view.center;167     newPoint.x -= 20.0;168     _imgV.center = newPoint;169     170     newPoint.x += 40.0;171     _imgV2.center = newPoint;172   };173   174   positionOperation();175 }176 177 178 #pragma mark - 绑定手势操作179 /**180  * 绑定拖动手势181  *182  * @param imgVCustom 绑定到图片视图对象实例183 */184 - (void)bindPan:(UIImageView *)imgVCustom {185   UIPanGestureRecognizer *recognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self186                                          action:@selector(handlePan:)];187   [imgVCustom addGestureRecognizer:recognizer];188 }189 190 /**191  * 绑定捏合手势192  *193  * @param imgVCustom 绑定到图片视图对象实例194 */195 - (void)bindPinch:(UIImageView *)imgVCustom {196   UIPinchGestureRecognizer *recognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self197                                            action:@selector(handlePinch:)];198   [imgVCustom addGestureRecognizer:recognizer];199   //[recognizer requireGestureRecognizerToFail:imgVCustom.gestureRecognizers.firstObject];200 }201 202 /**203  * 绑定旋转手势204  *205  * @param imgVCustom 绑定到图片视图对象实例206 */207 - (void)bindRotation:(UIImageView *)imgVCustom {208   UIRotationGestureRecognizer *recognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self209                                               action:@selector(handleRotation:)];210   [imgVCustom addGestureRecognizer:recognizer];211 }212 213 /**214  * 绑定点按手势215  *216  * @param imgVCustom 绑定到图片视图对象实例217 */218 - (void)bindTap:(UIImageView *)imgVCustom {219   UITapGestureRecognizer *recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self220                                          action:@selector(handleTap:)];221   //使用一根手指双击时,才触发点按手势识别器222   recognizer.numberOfTapsRequired = 2;223   recognizer.numberOfTouchesRequired = 1;224   [imgVCustom addGestureRecognizer:recognizer];225 }226 227 /**228  * 绑定长按手势229  *230  * @param imgVCustom 绑定到图片视图对象实例231 */232 - (void)bindLongPress:(UIImageView *)imgVCustom {233   UILongPressGestureRecognizer *recognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)];234   recognizer.minimumPressDuration = 0.5; //设置最小长按时间;默认为0.5秒235   [imgVCustom addGestureRecognizer:recognizer];236 }237 238 /**239  * 绑定轻扫手势;支持四个方向的轻扫,但是不同的方向要分别定义轻扫手势240 */241 - (void)bindSwipe {242   //向右轻扫手势243   UISwipeGestureRecognizer *recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self244                                            action:@selector(handleSwipe:)];245   recognizer.direction = UISwipeGestureRecognizerDirectionRight; //设置轻扫方向;默认是 UISwipeGestureRecognizerDirectionRight,即向右轻扫246   [self.view addGestureRecognizer:recognizer];247   [recognizer requireGestureRecognizerToFail:_customGestureRecognizer]; //设置以自定义挠痒手势优先识别248   249   //向左轻扫手势250   recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self251                               action:@selector(handleSwipe:)];252   recognizer.direction = UISwipeGestureRecognizerDirectionLeft;253   [self.view addGestureRecognizer:recognizer];254   [recognizer requireGestureRecognizerToFail:_customGestureRecognizer]; //设置以自定义挠痒手势优先识别255 }256 257 /**258  * 绑定自定义挠痒手势;判断是否有三次不同方向的动作,如果有则手势结束,将执行回调方法259 */260 - (void)bingCustomGestureRecognizer {261   //当 recognizer.state 为 UIGestureRecognizerStateEnded 时,才执行回调方法 handleCustomGestureRecognizer:262   263   //_customGestureRecognizer = [KMGestureRecognizer new];264   _customGestureRecognizer = [[KMGestureRecognizer alloc] initWithTarget:self265                                   action:@selector(handleCustomGestureRecognizer:)];266   [self.view addGestureRecognizer:_customGestureRecognizer];267 }268 269 - (void)layoutUI {270   //图片视图 _imgV271   UIImage *img = [UIImage imageNamed:@"Emoticon_tusiji_icon"];272   CGFloat cornerRadius = img.size.width;273   _imgV = [[UIImageView alloc] initWithImage:img];274   _imgV.frame = CGRectMake(20.0, 20.0,275               cornerRadius * 2, cornerRadius * 2);276   _imgV.userInteractionEnabled = YES;277   _imgV.layer.masksToBounds = YES;278   _imgV.layer.cornerRadius = cornerRadius;279   _imgV.layer.borderWidth = 2.0;280   _imgV.layer.borderColor = [UIColor grayColor].CGColor;281   [self.view addSubview:_imgV];282   283   //图片视图 _imgV2284   img = [UIImage imageNamed:@"Emoticon_tusiji_icon2"];285   cornerRadius = img.size.width;286   _imgV2 = [[UIImageView alloc] initWithImage:img];287   _imgV2.frame = CGRectMake(20.0, 40.0 + _imgV.frame.size.height,288                cornerRadius * 2, cornerRadius * 2);289   _imgV2.userInteractionEnabled = YES;290   _imgV2.layer.masksToBounds = YES;291   _imgV2.layer.cornerRadius = cornerRadius;292   _imgV2.layer.borderWidth = 2.0;293   _imgV2.layer.borderColor = [UIColor orangeColor].CGColor;294   [self.view addSubview:_imgV2];295   296   297   [self bindPan:_imgV];298   [self bindPinch:_imgV];299   [self bindRotation:_imgV];300   [self bindTap:_imgV];301   [self bindLongPress:_imgV];302   303   [self bindPan:_imgV2];304   [self bindPinch:_imgV2];305   [self bindRotation:_imgV2];306   [self bindTap:_imgV2];307   [self bindLongPress:_imgV2];308   309   //为了处理手势识别优先级的问题,这里需先绑定自定义挠痒手势310   [self bingCustomGestureRecognizer];311   [self bindSwipe];312 }313 314 @end