http://www.cnblogs.com/huangjianwu/p/4675648.html

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1、UIGestureRecognizer 介紹

手勢識別在 iOS 中非常重要，他極大地提高了移動設備的使用便捷性。

iOS 系統在 3.2 以后，他提供了一些常用的手勢（UIGestureRecognizer 的子類），開發者可以直接使用他們進行手勢操作。

• UIPanGestureRecognizer（拖動）

• UIPinchGestureRecognizer（捏合）

• UIRotationGestureRecognizer（旋轉）

• UITapGestureRecognizer（點按）

• UILongPressGestureRecognizer（長按）

• ?UISwipeGestureRecognizer（輕掃）

另外，可以通過繼承?UIGestureRecognizer 類，實現自定義手勢（手勢識別器類）。

PS：自定義手勢時，需要?#import <UIKit/UIGestureRecognizerSubclass.h>，一般需實現如下方法：

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 //以上方法在分類 UIGestureRecognizer (UIGestureRecognizerProtected) 中聲明，更多方法聲明請自行查看

UIGestureRecognizer 的繼承關系如下：

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2、手勢狀態

在六種手勢識別中，只有一種手勢是離散型手勢，他就是 UITapGestureRecognizer。

離散型手勢的特點就是：一旦識別就無法取消，而且只會調用一次手勢操作事件（初始化手勢時指定的回調方法）。

?換句話說其他五種手勢是連續型手勢，而連續型手勢的特點就是：會多次調用手勢操作事件，而且在連續手勢識別后可以取消手勢。從下圖可以看出兩者調用操作事件的次數是不同的：

手勢狀態枚舉如下：

1 typedef NS_ENUM(NSInteger, UIGestureRecognizerState) { 2 UIGestureRecognizerStatePossible, // 尚未識別是何種手勢操作（但可能已經觸發了觸摸事件），默認狀態 3 UIGestureRecognizerStateBegan, // 手勢已經開始，此時已經被識別，但是這個過程中可能發生變化，手勢操作尚未完成 4 UIGestureRecognizerStateChanged, // 手勢狀態發生轉變 5 UIGestureRecognizerStateEnded, // 手勢識別操作完成（此時已經松開手指） 6 UIGestureRecognizerStateCancelled, // 手勢被取消，恢復到默認狀態 7 UIGestureRecognizerStateFailed, // 手勢識別失敗，恢復到默認狀態 8 UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded // 手勢識別完成，同UIGestureRecognizerStateEnded 9 };

• 對于離散型手勢 UITapGestureRecgnizer 要么被識別，要么失敗，點按（假設點按次數設置為1，并且沒有添加長按手勢）下去一次不松開則此時什么也不會發生，松開手指立即識別并調用操作事件，并且狀態為3（已完成）。

• 但是連續型手勢要復雜一些，就拿旋轉手勢來說，如果兩個手指點下去不做任何操作，此時并不能識別手勢（因為我們還沒旋轉）但是其實已經觸發了觸摸開始事件，此時處于狀態0；如果此時旋轉會被識別，也就會調用對應的操作事件，同時狀態變成1（手勢開始），但是狀態1只有一瞬間；緊接著狀態變為2（因為我們的旋轉需要持續一會），并且重復調用操作事件（如果在事件中打印狀態會重復打印2）；松開手指，此時狀態變為3，并調用1次操作事件。

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3、使用手勢的步驟

使用手勢很簡單，分為三步：

創建手勢識別器對象實例。創建時，指定一個回調方法，當手勢開始，改變、或結束時，執行回調方法。

設置手勢識別器對象實例的相關屬性（可選部分）

添加到需要識別的 View 中。每個手勢只對應一個 View，當屏幕觸摸在 View 的邊界內時，如果手勢和預定的一樣，那就會執行回調方法。

PS：一個手勢只能對應一個 View，但是一個 View 可以有多個手勢。建議在真機上測試這些手勢，模擬器操作不太方便，可能導致認為手勢失效的情況。（模擬器測試捏合和旋轉手勢時，按住 option 鍵，再用觸摸板或鼠標操作）

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4、舉例說明?

功能描述：

附加到兩個圖片視圖 UIImageView 的有『拖動』、『捏合』、『旋轉』、『點按』；

而『輕掃』和『自定義手勢?KMGestureRecognizer』附加在根視圖 UIView 中。

拖動：進行當前圖片視圖位置移動

捏合：進行當前圖片視圖縮放

旋轉：進行當前圖片視圖角度旋轉

點按：雙擊恢復當前圖片視圖的縮放、角度旋轉、不透明度

長按：設置當前圖片視圖的不透明度為0.7

輕掃：左右輕掃設置兩個圖片視圖為居中，同時以垂直居中的特定偏移量定位

自定義手勢：撓癢功能，左右掃動共3次或以上，設置兩個圖片視圖為居中，同時以水平居中的特定偏移量定位

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效果如下：

KMGestureRecognizer.h

1 #import <UIKit/UIKit.h>2 3 typedef NS_ENUM(NSUInteger, Direction) {4 DirectionUnknown,5 DirectionLeft,6 DirectionRight7 };8 9 @interface KMGestureRecognizer : UIGestureRecognizer 10 @property (assign, nonatomic) NSUInteger tickleCount; //撓癢次數 11 @property (assign, nonatomic) CGPoint currentTickleStart; //當前撓癢開始坐標位置 12 @property (assign, nonatomic) Direction lastDirection; //最后一次撓癢方向 13 14 @end

KMGestureRecognizer.m

1 #import "KMGestureRecognizer.h"2 #import <UIKit/UIGestureRecognizerSubclass.h>3 4 @implementation KMGestureRecognizer5 #define kMinTickleSpacing 20.06 #define kMaxTickleCount 37 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]; //設置當前撓癢開始坐標位置 21 } 22 23 - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { 24 //『當前撓癢開始坐標位置』和『移動后坐標位置』進行 X 軸值比較，得到是向左還是向右移動 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 //移動的 X 軸間距值是否符合要求，足夠大 31 if (ABS(tickleSpacing) >= kMinTickleSpacing) { 32 //判斷是否有三次不同方向的動作，如果有則手勢結束，將執行回調方法 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(@"自定義手勢成功，將執行回調方法"); 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 @end21 22 @implementation ViewController23 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 - 處理手勢操作36 /**37 * 處理拖動手勢38 *39 * @param recognizer 拖動手勢識別器對象實例40 */41 - (void)handlePan:(UIPanGestureRecognizer *)recognizer {42 //視圖前置操作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 //計算速度向量的長度，當他小于200時，滑行會很短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: 1.98986658 59 //基于速度和速度因素計算一個終點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］和最大邊界值［self.view.bounds.size.width - cornerRadius］，以免拖動出屏幕界限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 動畫使 view 滑行到終點70 [UIView animateWithDuration:slideFactor*271 delay:072 options:UIViewAnimationOptionCurveEaseOut73 animations:^{74 recognizer.view.center = finalPoint;75 }76 completion:nil];77 }78 }79 80 /**81 * 處理捏合手勢82 *83 * @param recognizer 捏合手勢識別器對象實例84 */85 - (void)handlePinch:(UIPinchGestureRecognizer *)recognizer {86 CGFloat scale = recognizer.scale;87 recognizer.view.transform = CGAffineTransformScale(recognizer.view.transform, scale, scale); //在已縮放大小基礎下進行累加變化；區別于：使用 CGAffineTransformMakeScale 方法就是在原大小基礎下進行變化88 recognizer.scale = 1.0;89 }90 91 /**92 * 處理旋轉手勢93 *94 * @param recognizer 旋轉手勢識別器對象實例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 * 處理點按手勢 103 * 104 * @param recognizer 點按手勢識別器對象實例 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 * 處理長按手勢 115 * 116 * @param recognizer 點按手勢識別器對象實例 117 */ 118 - (void)handleLongPress:(UILongPressGestureRecognizer *)recognizer { 119 //長按的時候，設置不透明度為0.7 120 recognizer.view.alpha = 0.7; 121 } 122 123 /** 124 * 處理輕掃手勢 125 * 126 * @param recognizer 輕掃手勢識別器對象實例 127 */ 128 - (void)handleSwipe:(UISwipeGestureRecognizer *)recognizer { 129 //代碼塊方式封裝操作方法 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 //根據輕掃方向，進行不同控制 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 * 處理自定義手勢 160 * 161 * @param recognizer 自定義手勢識別器對象實例 162 */ 163 - (void)handleCustomGestureRecognizer:(KMGestureRecognizer *)recognizer { 164 //代碼塊方式封裝操作方法 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 - 綁定手勢操作 179 /** 180 * 綁定拖動手勢 181 * 182 * @param imgVCustom 綁定到圖片視圖對象實例 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 * 綁定捏合手勢 192 * 193 * @param imgVCustom 綁定到圖片視圖對象實例 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 * 綁定旋轉手勢 204 * 205 * @param imgVCustom 綁定到圖片視圖對象實例 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 * 綁定點按手勢 215 * 216 * @param imgVCustom 綁定到圖片視圖對象實例 217 */ 218 - (void)bindTap:(UIImageView *)imgVCustom { 219 UITapGestureRecognizer *recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self 220 action:@selector(handleTap:)]; 221 //使用一根手指雙擊時，才觸發點按手勢識別器 222 recognizer.numberOfTapsRequired = 2; 223 recognizer.numberOfTouchesRequired = 1; 224 [imgVCustom addGestureRecognizer:recognizer]; 225 } 226 227 /** 228 * 綁定長按手勢 229 * 230 * @param imgVCustom 綁定到圖片視圖對象實例 231 */ 232 - (void)bindLongPress:(UIImageView *)imgVCustom { 233 UILongPressGestureRecognizer *recognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)]; 234 recognizer.minimumPressDuration = 0.5; //設置最小長按時間；默認為0.5秒 235 [imgVCustom addGestureRecognizer:recognizer]; 236 } 237 238 /** 239 * 綁定輕掃手勢；支持四個方向的輕掃，但是不同的方向要分別定義輕掃手勢 240 */ 241 - (void)bindSwipe { 242 //向右輕掃手勢 243 UISwipeGestureRecognizer *recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self 244 action:@selector(handleSwipe:)]; 245 recognizer.direction = UISwipeGestureRecognizerDirectionRight; //設置輕掃方向；默認是 UISwipeGestureRecognizerDirectionRight，即向右輕掃 246 [self.view addGestureRecognizer:recognizer]; 247 [recognizer requireGestureRecognizerToFail:_customGestureRecognizer]; //設置以自定義撓癢手勢優先識別 248 249 //向左輕掃手勢 250 recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self 251 action:@selector(handleSwipe:)]; 252 recognizer.direction = UISwipeGestureRecognizerDirectionLeft; 253 [self.view addGestureRecognizer:recognizer]; 254 [recognizer requireGestureRecognizerToFail:_customGestureRecognizer]; //設置以自定義撓癢手勢優先識別 255 } 256 257 /** 258 * 綁定自定義撓癢手勢；判斷是否有三次不同方向的動作，如果有則手勢結束，將執行回調方法 259 */ 260 - (void)bingCustomGestureRecognizer { 261 //當 recognizer.state 為 UIGestureRecognizerStateEnded 時，才執行回調方法 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 //圖片視圖 _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 //圖片視圖 _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 //為了處理手勢識別優先級的問題，這里需先綁定自定義撓癢手勢 310 [self bingCustomGestureRecognizer]; 311 [self bindSwipe]; 312 } 313 314 @end

轉載于:https://www.cnblogs.com/DMDD/p/5074016.html

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