本篇IOS应用开发教程将为大家讲解IOS编程的知识点，看完这篇文章会让你对IOS编程的知识点有更加清晰的理解和运用。

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

功能描述：

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); //在已缩放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

希望这篇文章可以帮助到你。总之，同学们，你想要的职坐标IOS频道都能找到!