如何使用iOS手勢UIGestureRecognizer

UIKit中包含了UIGestureRecognizer類，用於檢測發生在裝置中的手勢。UIGestureRecognizer是一個抽象類別，定義了所有手勢的基本行為，它有下面一些子類用於處理具體的手勢：      1、拍擊UITapGestureRecognizer (任意次數的拍擊)      2、向裡或向外捏UIPinchGestureRecognizer (用於縮放)      3、搖動或者拖拽UIPanGestureRecognizer      4、滑動UISwipeGestureRecognizer (以任意方向)      5、旋轉UIRotationGestureRecognizer (手指朝相反方向移動)      6、長按UILongPressGestureRecognizer  對於不同類型的手勢辨識器，具有不同的配置屬性。比如UITapGestureRecognizer，可以配置拍擊次數。介面接收到手勢之後，可以發送一 個訊息，用於處理響應手勢動作後的任務。當然，不同的手勢辨識器，發送的訊息方法也會有所不同。下面列舉幾個具體範例程式碼：   一個手指，拍擊兩次手勢 // 建立一個手勢辨識器UITapGestureRecognizer *oneFingerTwoTaps =  [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerTwoTaps)] autorelease]; // Set required taps and number of touches[oneFingerTwoTaps setNumberOfTapsRequired:2];[oneFingerTwoTaps setNumberOfTouchesRequired:1]; // Add the gesture to the view[[self view] addGestureRecognizer:oneFingerTwoTaps]; 訊息方法oneFingerTwoTaps- (void)oneFingerTwoTaps{  NSLog(@"Action: One finger, two taps");}   兩個手指，拍擊兩次手勢 UITapGestureRecognizer *twoFingersTwoTaps =  [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersTwoTaps)] autorelease];[twoFingersTwoTaps setNumberOfTapsRequired:2];[twoFingersTwoTaps setNumberOfTouchesRequired:2];[[self view] addGestureRecognizer:twoFingersTwoTaps]; 訊息方法twoFingersTwoTaps- (void)twoFingersTwoTaps {  NSLog(@"Action: Two fingers, two taps");}    一個手指向上、向下滑動手勢 // 向上滑動UISwipeGestureRecognizer *oneFingerSwipeUp =  [[[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerSwipeUp:)] autorelease];[oneFingerSwipeUp setDirection:UISwipeGestureRecognizerDirectionUp];[[self view] addGestureRecognizer:oneFingerSwipeUp]; - (void)oneFingerSwipeUp:(UISwipeGestureRecognizer *)recognizer{  CGPoint point = [recognizer locationInView:[self view]];  NSLog(@"Swipe up - start location: %f,%f", point.x, point.y);} // 向下滑動UISwipeGestureRecognizer *oneFingerSwipeDown =  [[[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerSwipeDown:)] autorelease];[oneFingerSwipeDown setDirection:UISwipeGestureRecognizerDirectionDown];[[self view] addGestureRecognizer:oneFingerSwipeDown]; - (void)oneFingerSwipeDown:(UISwipeGestureRecognizer *)recognizer{  CGPoint point = [recognizer locationInView:[self view]];  NSLog(@"Swipe down - start location: %f,%f", point.x, point.y);}   旋轉手勢 UIRotationGestureRecognizer *twoFingersRotate =  [[[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersRotate:)] autorelease];[[self view] addGestureRecognizer:twoFingersRotate]; - (void)twoFingersRotate:(UIRotationGestureRecognizer *)recognizer{  // Convert the radian value to show the degree of rotation  NSLog(@"Rotation in degrees since last change: %f", [recognizer rotation] * (180 / M_PI));}   向裡或向外捏的手勢 UIPinchGestureRecognizer *twoFingerPinch =  [[[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingerPinch:)] autorelease];[[self view] addGestureRecognizer:twoFingerPinch]; - (void)twoFingerPinch:(UIPinchGestureRecognizer *)recognizer{  NSLog(@"Pinch scale: %f", recognizer.scale);}           UITapGestureRecognizer *twoFingersTwoTaps =  [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersTwoTaps)] autorelease];[twoFingersTwoTaps setNumberOfTapsRequired:2];[twoFingersTwoTaps setNumberOfTouchesRequired:2];[[self view] addGestureRecognizer:twoFingersTwoTaps]; 訊息方法twoFingersTwoTaps- (void)twoFingersTwoTaps {  NSLog(@"Action: Two fingers, two taps");}