UITapGestureRecognizer 的用法

最近在项目中用到了手势操作，键盘回收时还是挺常用的，现在总结下，多谢网络上大神们的分享。

先分享下我在项目中用的代码：

 UITapGestureRecognizer * mytap=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tap_gestureRecognizer:)];

     [self addGestureRecognizer:mytap];

     [mytap release];

 //收回键盘

 -(void)tap_gestureRecognizer:(UITapGestureRecognizer *)tap_gest

 {

     [self.scv_stockPriceTextField resignFirstResponder];

     [self.scv_stockAmoutTextField resignFirstResponder];

 }

//单指单击

2: UITapGestureRecognizer *singleFingerOne = [[UITapGestureRecognizer alloc] initWithTarget:self

3: action:@selector(handleSingleFingerEvent:)];

4: singleFingerOne.numberOfTouchesRequired = 1; //手指数

5: singleFingerOne.numberOfTapsRequired = 1; //tap次数

6: singleFingerOne.delegate = self;

7:

8: //单指双击

9: UITapGestureRecognizer *singleFingerTwo = [[UITapGestureRecognizer alloc] initWithTarget:self

10: action:@selector(handleSingleFingerEvent:)];

11: singleFingerTwo.numberOfTouchesRequired = 1;

12: singleFingerTwo.numberOfTapsRequired = 2;

13: singleFingerTwo.delegate = self;

14:

15: //双指单击

16: UITapGestureRecognizer *doubleFingerOne = [[UITapGestureRecognizer alloc] initWithTarget:self

17: action:@selector(handleDoubleFingerEvent:)];

18: doubleFingerOne.numberOfTouchesRequired = 2;

19: doubleFingerOne.numberOfTapsRequired = 1;

20: doubleFingerOne.delegate = self;

21:

22: UITapGestureRecognizer *doubleFingerTwo = [[UITapGestureRecognizer alloc] initWithTarget:self

23:    action:@selector(handleDoubleFingerEvent:)];

24: doubleFingerTwo.numberOfTouchesRequired = 2;

25: doubleFingerTwo.numberOfTapsRequired = 2;

26: doubleFingerTwo.delegate = self;

27:

28: //如果不加下面的话，当单指双击时，会先调用单指单击中的处理，再调用单指双击中的处理

29: [singleFingerOne requireGestureRecognizerToFail:singleFingerTwo];

30: //同理双指亦是如此

31: [doubleFingerOne requireGestureRecognizerToFail:doubleFingerTwo];

32:

33: [self.view addGestureRecognizer:singleFingerOne];

34: [self.view addGestureRecognizer:singleFingerTwo];

35: [self.view addGestureRecognizer:doubleFingerOne];

36: [self.view addGestureRecognizer:doubleFingerTwo];

37:

38: [singleFingerOne release];

39: [singleFingerTwo release];

40: [doubleFingerOne release];

41: [doubleFingerTwo release];

处理事件的方法，代码：

1: //处理单指事件

2: - (void)handleSingleFingerEvent:(UITapGestureRecognizer *)sender

3: {

4: if (sender.numberOfTapsRequired == 1) {

5: //单指单击

6: NSLog(@"单指单击");

7: }else if(sender.numberOfTapsRequired == 2){

8: //单指双击

9: NSLog(@"单指双击");

10: }

11: }

12: //处理双指事件

13: - (void)handleDoubleFingerEvent:(UITapGestureRecognizer *)sender

14: {

15: if (sender.numberOfTapsRequired == 1) {

16: //双指单击

17: NSLog(@"双指单击");

18: }else if(sender.numberOfTapsRequired == 2){

19: //双指双击

20: NSLog(@"双指双击");

21: }

22: }

将相应代码复制到你的工程中即可使用，由于代码中已经有详细的解释说明，这里就不在重复解释了。

代码中只是列举了单指与双指对于单击或多击的处理，同理多指的操作需修改numberOfTouchesRequired属性，对点击的次数需修改numberOfTapsRequired属性。

对于其他手势例如UISwipeGestureRecognizer，UILongPressGestureRecognizer,UILongPressGestureRecognizer的操作使用类似处理。

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、擦碰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：
http://www.ctolive.com/space-1023-do-blog-id-2107.html

标签：
Objective-C iOS

代码片段(5)

[代码] 一个手指，拍击两次手势

`01`	`// 创建一个手势识别器`

`02`	`UITapGestureRecognizer *oneFingerTwoTaps =`

`03`	`[[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerTwoTaps)] autorelease];`

04

`05`	`// Set required taps and number of touches`

`06`	`[oneFingerTwoTaps setNumberOfTapsRequired:2];`

`07`	`[oneFingerTwoTaps setNumberOfTouchesRequired:1];`

08

`09`	`// Add the gesture to the view`

`10`	`[[self view] addGestureRecognizer:oneFingerTwoTaps];`

11

`12`	`消息方法oneFingerTwoTaps`

`13`	`- (void)oneFingerTwoTaps`

14 {

`15`	`NSLog(@"Action: One finger, two taps");`

16 }

[代码] 两个手指，拍击两次手势

`01`	`UITapGestureRecognizer *twoFingersTwoTaps =`

`02`	`[[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersTwoTaps)] autorelease];`

`03`	`[twoFingersTwoTaps setNumberOfTapsRequired:2];`

`04`	`[twoFingersTwoTaps setNumberOfTouchesRequired:2];`

`05`	`[[self view] addGestureRecognizer:twoFingersTwoTaps];`

06

`07`	`消息方法twoFingersTwoTaps`

`08`	`- (void)twoFingersTwoTaps {`

`09`	`NSLog(@"Action: Two fingers, two taps");`

10 }

[代码] 一个手指向上、向下擦碰手势

01 // 向上擦碰

`02`	`UISwipeGestureRecognizer *oneFingerSwipeUp =`

`03`	`[[[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerSwipeUp:)] autorelease];`

`04`	`[oneFingerSwipeUp setDirection:UISwipeGestureRecognizerDirectionUp];`

`05`	`[[self view] addGestureRecognizer:oneFingerSwipeUp];`

06

`07`	`- (void)oneFingerSwipeUp:(UISwipeGestureRecognizer *)recognizer`

08 {

`09`	`CGPoint point = [recognizer locationInView:[self view]];`

`10`	`NSLog(@"Swipe up - start location: %f,%f", point.x, point.y);`

11 }

12

13 // 向下擦碰

`14`	`UISwipeGestureRecognizer *oneFingerSwipeDown =`

`15`	`[[[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerSwipeDown:)] autorelease];`

`16`	`[oneFingerSwipeDown setDirection:UISwipeGestureRecognizerDirectionDown];`

`17`	`[[self view] addGestureRecognizer:oneFingerSwipeDown];`

18

`19`	`- (void)oneFingerSwipeDown:(UISwipeGestureRecognizer *)recognizer`

20 {

`21`	`CGPoint point = [recognizer locationInView:[self view]];`

`22`	`NSLog(@"Swipe down - start location: %f,%f", point.x, point.y);`

23 }

[代码] 旋转手势

`1`	`UIRotationGestureRecognizer *twoFingersRotate =`

`2`	`[[[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersRotate:)] autorelease];`

`3`	`[[self view] addGestureRecognizer:twoFingersRotate];`

4

`5`	`- (void)twoFingersRotate:(UIRotationGestureRecognizer *)recognizer`

6 {

`7`	`// Convert the radian value to show the degree of rotation`

`8`	`NSLog(@"Rotation in degrees since last change: %f", [recognizer rotation] * (180 / M_PI));`

9 }

[代码] 向里或向外捏的手势

view
source

print ?

`1`	`UIPinchGestureRecognizer *twoFingerPinch =`

`2`	`[[[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingerPinch:)] autorelease];`

`3`	`[[self view] addGestureRecognizer:twoFingerPinch];`

4

`5`	`- (void)twoFingerPinch:(UIPinchGestureRecognizer *)recognizer`

6 {

`7`	`NSLog(@"Pinch scale: %f", recognizer.scale);` }

在 iPhone 或 iPad 的开发中，除了用 touchesBegan / touchesMoved / touchesEnded 这组方法来控制使用者的手指触控外，也可以用 UIGestureRecognizer 的衍生类別来进行判断。用 UIGestureRecognizer 的好处在于有现成的手势，开发者不用自己计算手指移动轨迹。UIGestureRecognizer的衍生类別有以下几种：

UITapGestureRecognizer
UIPinchGestureRecognizer
UIRotationGestureRecognizer
UISwipeGestureRecognizer
UIPanGestureRecognizer
UILongPressGestureRecognizer

从命名上不难了解這些类別所对应代表的手势，分別是
Tap（点一下）、Pinch（二指往內或往外拨动）、Rotation（旋转）、Swipe（滑动，快速移动）、Pan （拖移，慢速移动）以及 LongPress（长按）。這些手势別在使用上也很简单，只要在使用前定义并添加到对应的视图上即可。

// 定义一个 recognizer, 并加到需要偵測该手势的 UIView 元件上
- (void)viewDidLoad {
    UISwipeGestureRecognizer* recognizer;
    // handleSwipeFrom 是偵測到手势，所要呼叫的方法
    recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:selfaction:@selector(handleSwipeFrom)];
    // 不同的 Recognizer 有不同的实体变数
    // 例如 SwipeGesture 可以指定方向
    // 而 TapGesture 則可以指定次數
    recognizer.direction = UISwipeGestureRecognizerDirectionUp
    [self.view addGestureRecognizer:recognizer];
    [recognizer release];
 }

 - (void)handleSwipeFrom:(UISwipeGestureRecognizer*)recognizer {
    // 触发手勢事件后，在这里作些事情

    // 底下是刪除手势的方法
    [self.view removeGestureRecognizer:recognizer];
 }

问题來了。有些手势其实是互相关联的，例如 Tap 与 LongPress、Swipe与 Pan，或是 Tap 一次与Tap 兩次。当一個 UIView 同时添加兩个相关联的手势时，到底我这一下手指头按的要算是 Tap 还是 LongPress？如果照預设作法来看，只要「先滿足条件」的就会跳出并呼叫对应方法，举例来说，如果同时注册了 Pan 和 Swipe，只要手指头一移动就会触发 Pan 然后跳出，因而永远都不會发生 Swipe；单点与双点的情形也是一样，永远都只会触发单点，不會有双点。

那么这个问题有解吗？答案是肯定的，UIGestureRecognizer 有个方法叫做requireGestureRecognizerToFail，他可以指定某一个
recognizer，即便自己已经滿足條件了，也不會立刻触发，会等到该指定的 recognizer 确定失败之后才触发。以同时支持单点与双点的手势为例，代码如下：

- (void)viewDidLoad {
    // 单击的 Recognizer
    UITapGestureRecognizer* singleRecognizer;
    singleRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:selfaction:@selector(handleSingleTapFrom)];
    singleTapRecognizer.numberOfTapsRequired = 1; // 单击
    [self.view addGestureRecognizer:singleRecognizer];

    // 双击的 Recognizer
    UITapGestureRecognizer* double;
    doubleRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:selfaction:@selector(handleDoubleTapFrom)];
    doubleTapRecognizer.numberOfTapsRequired = 2; // 双击
    [self.view addGestureRecognizer:doubleRecognizer];

    // 关键在这一行，如果双击确定偵測失败才會触发单击
    [singleRecognizer requireGestureRecognizerToFail:doubleRecognizer];
    [singleRecognizer release];
    [doubleRecognizer release];
}

来源：http://blog.csdn.net/xiaoxuan415315/article/details/7788239