iOS 手势操作:拖动、捏合、旋转、点按、长按、轻扫、自定义

orangeladybug 发布于2年前
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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:

iOS 手势操作:拖动、捏合、旋转、点按、长按、轻扫、自定义

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:

iOS 手势操作:拖动、捏合、旋转、点按、长按、轻扫、自定义

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UIGestureRecognizerStateEnded
9 };
  • 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:

iOS 手势操作:拖动、捏合、旋转、点按、长按、轻扫、自定义

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 : UIGestureRecognizer
10 @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 : UIViewController
5 @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0.7
120     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:self
186                                                                                  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:self
197                                                                                      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:self
209                                                                                            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:self
220                                                                                  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:self
244                                                                                      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:self
251                                                            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:self
265                                                                     action:@selector(handleCustomGestureRecognizer:)];
266     [self.view addGestureRecognizer:_customGestureRecognizer];
267 }
268 
269 - (void)layoutUI {
270     //图片视图 _imgV
271     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 _imgV2
284     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
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