tap是指輕觸手勢(shì)。類(lèi)似鼠標(biāo)操作的點(diǎn)擊。從iOS 3.2版本開(kāi)始支持完善的手勢(shì)api：

• tap：輕觸
• long press：在一點(diǎn)上長(zhǎng)按
• pinch：兩個(gè)指頭捏或者放的操作
• pan：手指的拖動(dòng)
• swipe：手指在屏幕上很快的滑動(dòng)
• rotation：手指反向操作

這為開(kāi)發(fā)者編寫(xiě)手勢(shì)識(shí)別操作，提供了很大的方便，想想之前用android寫(xiě)手勢(shì)滑動(dòng)的代碼（ 編寫(xiě)android簡(jiǎn)單的手勢(shì)切換視圖示例 ），尤其感到幸福。

這里寫(xiě)一個(gè)簡(jiǎn)單的tap操作。在下面視圖的藍(lán)色視圖內(nèi)增加對(duì)tap的識(shí)別：

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當(dāng)用手指tap藍(lán)色視圖的時(shí)候，打印日志輸出：

代碼很簡(jiǎn)單，首先要聲明tap的recognizer：

UITapGestureRecognizer *recognizer=[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapFrom:)];?
[infoView addGestureRecognizer:recognizer];?
[recognizer release];

在這里：

• initWithTarget:self，要引用到Controller，因?yàn)橐话氵@部分代碼寫(xiě)在controller中，用self；
• action:@selector(handleTapFrom:)，賦值一個(gè)方法名，用于當(dāng)手勢(shì)事件發(fā)生后的回調(diào)；
• [infoView addGestureRecognizer:recognizer]，為view注冊(cè)這個(gè)手勢(shì)識(shí)別對(duì)象，這樣當(dāng)手指在該視圖區(qū)域內(nèi)，可引發(fā)手勢(shì)，之外則不會(huì)引發(fā)

對(duì)應(yīng)的回調(diào)方法：

-(void)handleTapFrom:(UITapGestureRecognizer *)recognizer{?
??? NSLog(@">>>tap it");?
}

controller相關(guān)方法完整的代碼（包含了一些與本文無(wú)關(guān)的視圖構(gòu)建代碼）：

// Implement loadView to create a view hierarchy programmatically, without using a nib.?
- (void)loadView {?
??? //去掉最頂端的狀態(tài)攔?
??? [[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation: UIStatusBarAnimationSlide];?
????
??? UIImage *image=[UIImage imageNamed:@"3.jpg"];?
????
??? //創(chuàng)建背景視圖?
??? self.view=[[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];?
??? UIImageView *backgroudView=[[UIImageView alloc] initWithImage:image];?
??? [self.view addSubview:backgroudView];?
????
??? ?
????
??? UIView *bottomView=[[UIView alloc]? initWithFrame:CGRectMake(0, 1024-70, 768, 70)];?
??? bottomView.backgroundColor=[UIColor grayColor];?
??? bottomView.alpha=0.8;?
????
??? //UIButton *backButton=[[UIButton alloc] initWithFrame:CGRectMake(10, 10, 100, 40)];?
??? UIButton *backButton=[UIButton buttonWithType: UIButtonTypeRoundedRect];?
??? [backButton setTitle:@"ok" forState:UIControlStateNormal];?
??? backButton.frame=CGRectMake(10, 15, 100, 40);?
????
??? [bottomView addSubview:backButton];?
????
??? [self.view addSubview:bottomView];?
????
??? UIView *infoView=[[UIView alloc] initWithFrame:CGRectMake(200, 700, 768-400, 70)];?
??? infoView.backgroundColor=[UIColor blueColor];?
??? infoView.alpha=0.6;?
??? infoView.layer.cornerRadius=6;?
??? infoView.layer.masksToBounds=YES;?
??? [self.view addSubview:infoView];?
????
??? UITapGestureRecognizer *recognizer=[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapFrom:)];?
??? [infoView addGestureRecognizer:recognizer];?
??? [recognizer release];?
}

-(void)handleTapFrom:(UITapGestureRecognizer *)recognizer{?
??? NSLog(@">>>tap it");?
}

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翻頁(yè)效果，類(lèi)似下面的樣子：

在電子書(shū)應(yīng)用中會(huì)很常見(jiàn)。這里需要兩個(gè)要點(diǎn)：

• 翻頁(yè)動(dòng)畫(huà)
• 手勢(shì)上下輕掃（swipe）的處理

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先說(shuō)一下輕掃（swipe）的實(shí)現(xiàn)，可以參考 編寫(xiě)簡(jiǎn)單的手勢(shì)示例：Tap 了解手勢(shì)種類(lèi)。

在viewDidLoad方法中注冊(cè)了對(duì)上、下、左、右四個(gè)方向輕松的處理方法：

- (void)viewDidLoad {?
????
??? UISwipeGestureRecognizer *recognizer;?
????
??? recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];?
??? [recognizer setDirection:(UISwipeGestureRecognizerDirectionRight)];?
??? [[self view] addGestureRecognizer:recognizer];?
??? [recognizer release];?
????
??? recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];?
??? [recognizer setDirection:(UISwipeGestureRecognizerDirectionUp)];?
??? [[self view] addGestureRecognizer:recognizer];?
??? [recognizer release];?
????
??? recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];?
??? [recognizer setDirection:(UISwipeGestureRecognizerDirectionDown)];?
??? [[self view] addGestureRecognizer:recognizer];?
??? [recognizer release];?
????
??? recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];?
??? [recognizer setDirection:(UISwipeGestureRecognizerDirectionLeft)];?
??? [[self view] addGestureRecognizer:recognizer];?
??? [recognizer release];?
????
????
??? [super viewDidLoad];

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可以看到，都是同一個(gè)方法，handleSwipeFrom。

在該方法中，再識(shí)別具體是哪個(gè)方向的輕掃手勢(shì)，比如判斷是向下的輕掃：

-(void)handleSwipeFrom:(UISwipeGestureRecognizer *)recognizer {?
??? NSLog(@"Swipe received.");?
????
??? if (recognizer.direction==UISwipeGestureRecognizerDirectionDown) {?
??????? NSLog(@"swipe down");

判斷是向上的輕掃：

if (recognizer.direction==UISwipeGestureRecognizerDirectionUp) {?
??? NSLog(@"swipe up");

有關(guān)動(dòng)畫(huà)的處理，比如向下（往回）翻頁(yè)，類(lèi)似這樣：

[UIView beginAnimations:@"animationID" context:nil];?
[UIView setAnimationDuration:0.7f];?
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];?
[UIView setAnimationRepeatAutoreverses:NO];?
[UIView setAnimationTransition:UIViewAnimationTransitionCurlDown forView:self.view cache:YES];

[currentView removeFromSuperview];?
[self.view addSubview:contentView];

[UIView commitAnimations];

向上（向前）翻頁(yè)，只需改為：

[UIView beginAnimations:@"animationID" context:nil];?
[UIView setAnimationDuration:0.7f];?
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];?
[UIView setAnimationRepeatAutoreverses:NO];?
[UIView setAnimationTransition: UIViewAnimationTransitionCurlUp ?forView:self.view cache:YES];

[currentView removeFromSuperview];?
[self.view addSubview:contentView];

[UIView commitAnimations];

如果是電子書(shū)，還需要考慮一個(gè)問(wèn)題，就是有多個(gè)頁(yè)面（圖形），比如50頁(yè)。那么需要有一個(gè)數(shù)據(jù)結(jié)構(gòu)來(lái)保存這些頁(yè)面的圖片路徑：

• objc數(shù)據(jù)結(jié)構(gòu)，比如數(shù)組
• sqlite數(shù)據(jù)庫(kù)表

這樣，寫(xiě)一套翻頁(yè)代碼和加載什么圖形之間就可以解耦。

本文示例使用的是數(shù)組，類(lèi)似這樣：

pages=[[NSArray alloc] initWithObjects:@"1.jpg",@"2.jpg",@"3.jpg",@"4.jpg",@"5.jpg",@"6.jpg",?
???????????????? nil];

圖片保存在resources下。

為了能讓上頁(yè)下頁(yè)翻頁(yè)的時(shí)候找到關(guān)聯(lián)的頁(yè)面，采用了如下機(jī)制：

• 將圖片封裝為UIImageView顯示
• 可以為UIImageView設(shè)置一個(gè)tag值，值為數(shù)組下標(biāo)+1
• 這樣，上級(jí)view有方法能根據(jù)tag查詢(xún)到UIImageView，比如：UIView *currentView=[self.view viewWithTag:currentTag];
• 設(shè)置一個(gè)成員變量currentTag保存當(dāng)前的tag值

比如這樣，當(dāng)應(yīng)用加載的時(shí)候顯示第一頁(yè)：

??? currentTag=1;?
????
??? NSString *path = [[NSBundle mainBundle] pathForResource:@"pageflip1" ofType:@"mp3"];?
??? player=[[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:path] error:NULL];?
????
??? //[[UIApplication sharedApplication] setStatusBarHidden:YES animated:NO];?
??? [[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation: UIStatusBarAnimationSlide];?
??? UIImageView *contentView = [[UIImageView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];??
??? [contentView setImage:[UIImage imageNamed:[pages objectAtIndex:(currentTag-1)]]];??
??? [contentView setUserInteractionEnabled:YES];?
??? contentView.tag=currentTag;

在翻頁(yè)時(shí)的處理：

if (currentTag<[pages count]) {?
??? UIView *currentView=[self.view viewWithTag:currentTag];?
??? currentTag++;?
????
??? UIImageView *contentView = [[UIImageView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];?
??? [contentView setImage:[UIImage imageNamed:[pages objectAtIndex:(currentTag-1)]]];??
??? [contentView setUserInteractionEnabled:YES];?
??? contentView.tag=currentTag;?
????
??? [UIView beginAnimations:@"animationID" context:nil];?
??? [UIView setAnimationDuration:0.7f];?
??? [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];?
??? [UIView setAnimationRepeatAutoreverses:NO];?
??? [UIView setAnimationTransition:UIViewAnimationTransitionCurlUp forView:self.view cache:YES];?
????
??? [currentView removeFromSuperview];?
??? [self.view addSubview:contentView];?
????
??? [UIView commitAnimations];

Gesture手勢(shì) 轉(zhuǎn)自http://blog.sina.com.cn/s/blog_8a6c97b5010106zq.html