[转载]手势做的简单的翻页效果 翻书带背影效果

原文地址：手势做的简单的翻页效果作者：醉吻花颜
翻页效果，类似下面的样子：





在电子书应用中会很常见。这里需要两个要点：

翻页动画
手势上下轻扫（swipe）的处理

先说一下轻扫（swipe）的实现，可以参考编写简单的手势示例：Tap了解手势种类。

在viewDidLoad方法中注册了对上、下、左、右四个方向轻松的处理方法：

- (void)viewDidLoad {



UISwipeGestureRecognizer *recognizer;



recognizer =[[UISwipeGestureRecognizer alloc] initWithTarget:selfaction:@selector(handleSwipeFrom:)];

[recognizersetDirection:(UISwipeGestureRecognizerDirectionRight)];

[[self view]addGestureRecognizer:recognizer];

[recognizerrelease];



recognizer =[[UISwipeGestureRecognizer alloc] initWithTarget:selfaction:@selector(handleSwipeFrom:)];

[recognizersetDirection:(UISwipeGestureRecognizerDirectionUp)];

[[self view]addGestureRecognizer:recognizer];

[recognizerrelease];



recognizer =[[UISwipeGestureRecognizer alloc] initWithTarget:selfaction:@selector(handleSwipeFrom:)];

[recognizersetDirection:(UISwipeGestureRecognizerDirectionDown)];

[[self view]addGestureRecognizer:recognizer];

[recognizerrelease];



recognizer =[[UISwipeGestureRecognizer alloc] initWithTarget:selfaction:@selector(handleSwipeFrom:)];

[recognizersetDirection:(UISwipeGestureRecognizerDirectionLeft)];

[[self view]addGestureRecognizer:recognizer];

[recognizerrelease];





[superviewDidLoad];



可以看到，都是同一个方法，handleSwipeFrom。

在该方法中，再识别具体是哪个方向的轻扫手势，比如判断是向下的轻扫：

-(void)handleSwipeFrom:(UISwipeGestureRecognizer *)recognizer{

NSLog(@"Swipe received.");



if(recognizer.direction==UISwipeGestureRecognizerDirectionDown){

NSLog(@"swipe down");

判断是向上的轻扫：

if (recognizer.direction==UISwipeGestureRecognizerDirectionUp){

NSLog(@"swipe up");

有关动画的处理，比如向下（往回）翻页，类似这样：

[UIView beginAnimations:@"animationID" context:nil];

[UIView setAnimationDuration:0.7f];

[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];

[UIView setAnimationRepeatAutoreverses:NO];

[UIView setAnimationTransition:UIViewAnimationTransitionCurlDownforView:self.view cache:YES];

[currentView removeFromSuperview];

[self.view addSubview:contentView];

[UIView commitAnimations];

向上（向前）翻页，只需改为：

[UIView beginAnimations:@"animationID" context:nil];

[UIView setAnimationDuration:0.7f];

[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];

[UIView setAnimationRepeatAutoreverses:NO];

[UIViewsetAnimationTransition:UIViewAnimationTransitionCurlUpforView:self.view cache:YES];

[currentView removeFromSuperview];

[self.view addSubview:contentView];

[UIView commitAnimations];

如果是电子书，还需要考虑一个问题，就是有多个页面（图形），比如50页。那么需要有一个数据结构来保存这些页面的图片路径：

objc数据结构，比如数组
sqlite数据库表

这样，写一套翻页代码和加载什么图形之间就可以解耦。

本文示例使用的是数组，类似这样：

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

nil];

图片保存在resources下。

为了能让上页下页翻页的时候找到关联的页面，采用了如下机制：

将图片封装为UIImageView显示
可以为UIImageView设置一个tag值，值为数组下标+1
这样，上级view有方法能根据tag查询到UIImageView，比如：UIView*currentView=[self.view viewWithTag:currentTag];
设置一个成员变量currentTag保存当前的tag值

比如这样，当应用加载的时候显示第一页：

currentTag=1;



NSString*path = [[NSBundle mainBundle] pathForResource:@"pageflip1"ofType:@"mp3"];

player=[[***AudioPlayer alloc] initWithContentsOfURL:[NSURLfileURLWithPath:path] error:NULL];



//[[UIApplication sharedApplication] setStatusBarHidden:YESanimated:NO];

[[UIApplication sharedApplication] setStatusBarHidden:YESwithAnimation: UIStatusBarAnimationSlide];

UIImageView*contentView = [[UIImageView alloc] initWithFrame:[[UIScreenmainScreen] applicationFrame]];

[contentViewsetImage:[UIImage imageNamed:[pagesobjectAtIndex:(currentTag-1)]]];

[contentViewsetUserInteractionEnabled:YES];

contentView.tag=currentTag;

在翻页时的处理：

if (currentTag<[pages count]) {

UIView*currentView=[self.view viewWithTag:currentTag];

currentTag++;



UIImageView*contentView = [[UIImageView alloc] initWithFrame:[[UIScreenmainScreen] applicationFrame]];

[contentViewsetImage:[UIImage imageNamed:[pagesobjectAtIndex:(currentTag-1)]]];

[contentViewsetUserInteractionEnabled:YES];

contentView.tag=currentTag;



[UIViewbeginAnimations:@"animationID" context:nil];

[UIViewsetAnimationDuration:0.7f];

[UIViewsetAnimationCurve:UIViewAnimationCurveEaseInOut];

[UIViewsetAnimationRepeatAutoreverses:NO];

[UIViewsetAnimationTransition:UIViewAnimationTransitionCurlUpforView:self.view cache:YES];



[currentViewremoveFromSuperview];

[self.viewaddSubview:contentView];



[UIViewcommitAnimations];

原文来自:http://marshal.easymorse.com/archives/3760