Question

如何使用iOS手势UIGestureRecognizer

Answer 1

　　UIKit中包含了UIGestureRecognizer类，用于检测发生在设备中的手势。UIGestureRecognizer是一个抽象类，定义了所有手势的基本行为，它有下面一些子类用于处理具体的手势：

　　1、拍击UITapGestureRecognizer (任意次数的拍击)
　　2、向里或向外捏UIPinchGestureRecognizer (用于缩放)
　　3、摇动或者拖拽UIPanGestureRecognizer
　　4、滑动UISwipeGestureRecognizer (以任意方向)
　　5、旋转UIRotationGestureRecognizer (手指朝相反方向移动)
　　6、长按UILongPressGestureRecognizer

　　对于不同类型的手势识别器，具有不同的配置属性。比如UITapGestureRecognizer，可以配置拍击次数。界面接收到手势之后，可以发送一 个消息，用于处理响应手势动作后的任务。当然，不同的手势识别器，发送的消息方法也会有所不同。下面列举几个具体示例代码：

　　

　　一个手指，拍击两次手势
　　复制代码
　　// 创建一个手势识别器
　　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];

　　消息方法oneFingerTwoTaps
　　- (void)oneFingerTwoTaps
　　{
　　NSLog(@"Action: One finger, two taps");
　　}
　　复制代码
　　

　　两个手指，拍击两次手势
　　复制代码
　　UITapGestureRecognizer *twoFingersTwoTaps =
　　[[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersTwoTaps)] autorelease];
　　[twoFingersTwoTaps setNumberOfTapsRequired:2];
　　[twoFingersTwoTaps setNumberOfTouchesRequired:2];
　　[[self view] addGestureRecognizer:twoFingersTwoTaps];

　　消息方法twoFingersTwoTaps
　　- (void)twoFingersTwoTaps {
　　NSLog(@"Action: Two fingers, two taps");
　　}
　　复制代码
　　

　　一个手指向上、向下滑动手势
　　复制代码
　　// 向上滑动
　　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);
　　}

　　// 向下滑动
　　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);
　　}
　　复制代码
　　

　　旋转手势
　　复制代码
　　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));
　　}
　　复制代码
　　

　　向里或向外捏的手势
　　复制代码
　　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];

　　消息方法twoFingersTwoTaps
　　- (void)twoFingersTwoTaps {
　　NSLog(@"Action: Two fingers, two taps");
　　}