手势操作---识别单击还是双击
在视图上同时识别单击手势和双击手势的问题在于，当检测到一个单击操作时，无法确定是确实是一个单击操作或者只是双击操作中的第一次点击。解决这个问题的方法就是:在检测到单击时，需要等一段时间等待第二次点击，如果没有第二次点击，则为单击操作；如果有第二次点击，则为双击操作。
检测手势有两种方法，一种是定制子视图，重写视图从UIResponder类中继承来的事件处理方法,即touchesBegan:withEvent:等一系列方法来检测手势；另一个方法是使用手势识别器，即UIGestureRecognizer的各种具体子类。
一.重写事件处理方法

代码如下：

- (id)init { 
    if ((self = [super init])) { 
        self.userInteractionEnabled = YES; 
        self.multipleTouchEnabled = YES; 
        // ... 
    } 
    return self; 
} 
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event 
{ 
    [NSObject cancelPreviousPerformRequestsWithTarget:self]; 
    UITouch *touch = [touches anyObject]; 
    CGPoint touchPoint = [touch locationInView:self]; 
 
    if (touch.tapCount == 1) { 
        [self performSelector:@selector(handleSingleTap:) withObject:[NSValue valueWithCGPoint:touchPoint] afterDelay:0.3]; 
    }else if(touch.tapCount == 2) 
    { 
        [self handleDoubleTap:[NSValue valueWithCGPoint:touchPoint]]; 
    } 
} 
 
-(void)handleSingleTap:(NSValue*)pointValue 
{ 
    CGPoint touchPoint = [pointValue CGPointValue]; 
    //... 
} 
 
-(void)handleDoubleTap:(NSValue*)pointValue 
{ 
    CGPoint touchPoint = [pointValue CGPointValue]; 
    //... 
} 

首先确认定制视图的userInteractionEnabled和multipleTouchEnabled属性都为YES.
在touchesEnded:withEvent:方法中，如果是第一次触摸结束，则cancelPreviousPerformRequestsWithTarget:方法不会起作用，因为self未调度任何方法，此时tapCount为1，使用performSelector:withObject:afterDelay:调用单击事件处理方法，在0.3s钟后执行。代码如下：

[self performSelector:@selector(handleSingleTap:) withObject:[NSValue valueWithCGPoint:touchPoint] afterDelay:0.3];

如果这是一个单击操作，则后面0.3钟内不会再有触摸事件，则handleSingleTap:方法执行，这样识别出了单击操作。
如果这是一个双击操作，则第二次点击在0.3s内触发，在第二次触摸操作的touchesEnded:withEvent:方法中，cancelPreviousPerformRequestsWithTarget:首先会取消之前对handleSingleTap:方法的调度，使之不会执行，然后在调用handleDoubleTap:方法处理双击操作。
二.使用Gesture Recognizer
使用Gesture Recognizer识别就会简单许多，只需添加两个手势识别器，分别检测单击和双击事件，设置必要的属性即可。

代码如下：

- (id)init { 
    if ((self = [super init])) { 
    self.userInteractionEnabled = YES; 
        UITapGestureRecognizer *singleTapGesture = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(handleSingleTap:)]; 
        singleTapGesture.numberOfTapsRequired = 1; 
        singleTapGesture.numberOfTouchesRequired  = 1; 
        [self addGestureRecognizer:singleTapGesture]; 
 
        UITapGestureRecognizer *doubleTapGesture = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(handleDoubleTap:)]; 
        doubleTapGesture.numberOfTapsRequired = 2; 
        doubleTapGesture.numberOfTouchesRequired = 1; 
        [self addGestureRecognizer:doubleTapGesture]; 
 
        [singleTapGesture requireGestureRecognizerToFail:doubleTapGesture]; 
    } 
    return self; 
} 
-(void)handleSingleTap:(UIGestureRecognizer *)sender{ 
    CGPoint touchPoint = [sender locationInView:self]; 
    //... 
} 
-(void)handleDoubleTap:(UIGestureRecognizer *)sender{ 
    CGPoint touchPoint = [sender locationInView:self]; 
    //... 
} 

唯一需要注意的是代码如下：

[singleTapGesture requireGestureRecognizerToFail:doubleTapGesture]; 
这句话的意思时，只有当doubleTapGesture识别失败的时候(即识别出这不是双击操作)，singleTapGesture才能开始识别，同我们一开始讲的是同一个问题。

UIGestureRecognizer小应用
1、轻拍手势：双指、单击，修改imageView的frame为(0,0,320,200)
2、长按手指：单指，修改imageView的alpha=0.5
3、实现平移、旋转、捏合
4、轻扫：竖向轻扫实现图：像随机切换显示；横向轻扫实现：图像消失，随机修改imageview的背景颜色
5、imageview每次只能添加一种手势识别器。

代码如下：

#define _originalRect CGRectMake(10, 50, 300, 450) 
#define _originalImageName  @"h4.jpeg" 
 
#import "HMTRootViewController.h" 
 
@interface HMTRootViewController (){ 
 
    UITapGestureRecognizer       * _tapGesture; 
    UILongPressGestureRecognizer * _longGesture; 
    UIPanGestureRecognizer       * _panGesture; 
    UIRotationGestureRecognizer  * _rotateGesture; 
    UIPinchGestureRecognizer     * _pinchGesture; 
    UISwipeGestureRecognizer     * _verticalSwipeGesture; 
    UISwipeGestureRecognizer     * _horizontanlSwipeGesture; 
    BOOL isTopDownOfRightLeft;    // 垂直滑动是YES,水平滑动是NO 
     
} 
 
@property (nonatomic,retain) UIButton * button; 
@property (nonatomic,retain) UIImageView * imageView; 
 
@end 
 
@implementation HMTRootViewController 
 
- (void)dealloc{ 
     
    RELEASE_SAFELY(_imageView); 
    RELEASE_SAFELY(_button); 
    [super dealloc]; 
 
} 
 
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil 
{ 
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; 
    if (self) { 
        // Custom initialization 
        isTopDownOfRightLeft = YES; 
    } 
    return self; 
} 
 
- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 
    // Do any additional setup after loading the view. 
     
    [self createButtonView]; 
    [self createImageView]; 
 
} 
 
#pragma mark - 设置图像 
- (void)createImageView{ 
     
    self.imageView = [[UIImageView alloc]initWithImage:[UIImage imageNamed:_originalImageName]]; 
    _imageView.frame = CGRectMake(10, 50, 300, 450); 
    _imageView.userInteractionEnabled = YES; 
    [self.view addSubview:_imageView]; 
    [_imageView release]; 
} 
 
 
 
#pragma mark - 设置手势 
 
#pragma mark  点击手势 
- (void)createTapGestureRecognizer{ 
    
 
    _tapGesture = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(TapGestureRecognizer:)]; 
    _tapGesture.numberOfTapsRequired = 1; 
    _tapGesture.numberOfTouchesRequired = 2; 
    [self.imageView addGestureRecognizer:_tapGesture]; 
    [_tapGesture release]; 
 
} 
 
- (void)TapGestureRecognizer:(UITapGestureRecognizer *)tapGesture{ 
 
    self.imageView.frame = CGRectMake(0, 0, 320, 200); 
    NSLog(@"%@",NSStringFromCGRect(self.imageView.frame)); 
 
}  
 
#pragma mark  长按手势 
- (void)createLongGestureRecognizer{ 
     
    _longGesture = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longGestureRecognizer:)]; 
    _longGesture.numberOfTouchesRequired = 1; 
    _longGesture.minimumPressDuration = 1.0; 
    [self.imageView addGestureRecognizer:_longGesture]; 
    [_longGesture release]; 
     
} 
 
- (void)longGestureRecognizer:(UILongPressGestureRecognizer *)longGesture{ 
 
    self.imageView.alpha = 0.5; 
    NSLog(@"%s",__FUNCTION__); 
 
} 
 
#pragma mark 平移拖拽手势 
- (void)createPanGestureRecognizer{ 
     
    _panGesture = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(panGestureRecognizer:)]; 
    [self.imageView addGestureRecognizer:_panGesture]; 
    [_panGesture release]; 
     
} 
 
- (void)panGestureRecognizer:(UIPanGestureRecognizer *)panGesture{ 
     
    NSLog(@"%s",__FUNCTION__); 
  
    CGPoint txty = [panGesture translationInView:self.view]; 
    self.imageView.transform = CGAffineTransformTranslate(self.imageView.transform, txty.x, txty.y); 
     
    [panGesture setTranslation:CGPointMake(0, 0) inView:self.view]; 
     
} 
 
#pragma mark 旋转手势 
- (void)createRotationGestureRecognizer{ 
     
     
    _rotateGesture = [[UIRotationGestureRecognizer alloc]initWithTarget:self action:@selector(rotationGestureRecognizer:)]; 
    [self.imageView addGestureRecognizer:_rotateGesture]; 
    [_rotateGesture release]; 
     
} 
 
- (void)rotationGestureRecognizer:(UIRotationGestureRecognizer *)rotateGesture{ 
     
    NSLog(@"%s",__FUNCTION__); 
    self.imageView.transform = CGAffineTransformRotate(self.imageView.transform, rotateGesture.rotation); 
    rotateGesture.rotation = 0; 
     
} 
 
#pragma mark 捏合缩放手势 
- (void)createPinchGestureRecognizer{ 
     
    _pinchGesture = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:@selector(pinchGestureRecognizer:)]; 
    [self.imageView addGestureRecognizer:_pinchGesture]; 
    [_pinchGesture release]; 
     
} 
 
- (void)pinchGestureRecognizer:(UIPinchGestureRecognizer *)pinchGesture{ 
     
    NSLog(@"%s",__FUNCTION__); 
    self.imageView.transform = CGAffineTransformScale(self.imageView.transform, pinchGesture.scale, pinchGesture.scale); 
    pinchGesture.scale = 1; 
     
} 
 
#pragma mark - 轻扫手势 
#pragma mark 上下 竖 垂直轻扫 
- (void)createVerticalSwipeGestureRecognizer{ 
    
    _verticalSwipeGesture = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipeGestureRecognizer:)]; 
    _verticalSwipeGesture.direction = UISwipeGestureRecognizerDirectionUp | UISwipeGestureRecognizerDirectionDown; 
    [self.imageView addGestureRecognizer:_verticalSwipeGesture]; 
    [_verticalSwipeGesture release]; 
} 
 
#pragma mark 水平 左右轻扫 
- (void)createHorizontanlSwipeGesture{ 
     
    _horizontanlSwipeGesture = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipeGestureRecognizer:)]; 
    _horizontanlSwipeGesture.direction = UISwipeGestureRecognizerDirectionLeft |UISwipeGestureRecognizerDirectionRight; 
    [self.imageView addGestureRecognizer:_horizontanlSwipeGesture]; 
     
} 
 
- (void)swipeGestureRecognizer:(UISwipeGestureRecognizer *)swipeGesture{ 
     
    NSLog(@"%s",__FUNCTION__); 
    
    if (swipeGesture.direction == (UISwipeGestureRecognizerDirectionUp|UISwipeGestureRecognizerDirectionDown)) { 
        self.imageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"h%i.jpeg",arc4random()%7+1]]; 
        ; 
 
    }else if (swipeGesture.direction == (UISwipeGestureRecognizerDirectionLeft|UISwipeGestureRecognizerDirectionRight)){ 
     
        self.imageView.image = nil; 
        self.imageView.backgroundColor = [UIColor colorWithRed:arc4random()%256/255.0 green:arc4random()%256/255.0 blue:arc4random()%256/255.0 alpha:1.0]; 
    } 
} 
 
 
#pragma mark - 设置按钮 
- (void)createButtonView{ 
     
    NSArray * buttonArray = @[@"轻点",@"长按",@"平移",@"旋转",@"捏合",@"轻扫"]; 
     
    for (int i = 0; i < [buttonArray count]; i++) { 
         
        self.button = [UIButton buttonWithType:UIButtonTypeSystem]; 
        _button.frame = CGRectMake(10+50*i, 500, 50, 48); 
        [_button setTitle:[buttonArray objectAtIndex:i] forState:UIControlStateNormal]; 
        [_button addTarget:self action:@selector(onClikButton:) forControlEvents:UIControlEventTouchUpInside]; 
        _button.tag = i; 
        [self.view addSubview:_button]; 
    } 
   
} 
 
- (void)onClikButton:(UIButton *)button{ 
     
    [self resetImageView]; 
    switch (button.tag) { 
        case 0: 
   
            [self createTapGestureRecognizer]; 
            break; 
        case 1: 
  
            [self createLongGestureRecognizer]; 
            break; 
        case 2: 
         
            [self createPanGestureRecognizer]; 
            break; 
        case 3: 
            
            [self createRotationGestureRecognizer]; 
            break; 
        case 4: 
             
            [self createPinchGestureRecognizer]; 
            break; 
        case 5: 
            if (isTopDownOfRightLeft == YES) { 
                [self createVerticalSwipeGestureRecognizer]; 
                isTopDownOfRightLeft = NO; 
            } else { 
                [self createHorizontanlSwipeGesture]; 
                isTopDownOfRightLeft = YES; 
            } 
            break; 
        default: 
            break; 
    } 
     
} 
 
#pragma mark - 重置imageView 
- (void)resetImageView 
{ 
    for (int i = 0; i < [self.imageView.gestureRecognizers count]; i++) { 
        [self.imageView removeGestureRecognizer:[self.imageView.gestureRecognizers objectAtIndex:i]]; 
    } 
    self.imageView.alpha = 1.0; 
    self.imageView.transform = CGAffineTransformIdentity; 
    self.imageView.frame = _originalRect; 
    self.imageView.image = [UIImage imageNamed:_originalImageName]; 
} 
 
 
- (void)didReceiveMemoryWarning 
{ 
    [super didReceiveMemoryWarning]; 
    // Dispose of any resources that can be recreated. 
} 
 
@end