iOS开发中的几个手势操作实例分享

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

- (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。

[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。

- (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

[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。

#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