使用ListView FastScroller，默认滑块和自定义滑块图片的样子：
设置快速滚动属性很容易，只需在布局的xml文件里设置属性即可：
<ListView android:id=”@+id/listView” android:layout_width=”fill_parent”
android:layout_height=”fill_parent” android:fastScrollEnabled=”true”
android:focusable=”true” />
但是有时候会发现设置属性无效，滚动ListView并未出现滑块。原因是该属性生效有最小记录限制。当ListView记录能够在4屏以内显示（也就是说滚动4页）就不会出现滑块。可能是api设计者认为这么少的记录不需要快速滚动。
我的依据是android源代码，见FastScroller的常量声明：
// Minimum number of pages to justify showing a fast scroll thumb
private static int MIN_PAGES = 4;
以及：
// Are there enough pages to require fast scroll? Recompute only if total count changes
if (mItemCount != totalItemCount && visibleItemCount > 0) {
mItemCount = totalItemCount;
mLongList = mItemCount / visibleItemCount >= MIN_PAGES;
}
通篇查看了ListView及其超累AbsListView，都未找到自定义图片的设置接口。看来是没打算让开发者更改了。但是用户要求我们自定义这个图片。那只能用非常手段了。
经过分析发现，该图片是ListView超类AbsListView的一个成员mFastScroller对象的成员 mThumbDrawable。这里mThumbDrawable是Drawable类型的。mFastScroller是FastScroller类 型，这个类型比较麻烦，类的声明没有modifier，也就是default（package），只能供包内的类调用。
因此反射代码写的稍微麻烦一些：
try {
Field f = AbsListView.class.getDeclaredField(“mFastScroller”);
f.setAccessible(true);
Object o=f.get(listView);
f=f.getType().getDeclaredField(“mThumbDrawable”);
f.setAccessible(true);
Drawable drawable=(Drawable) f.get(o);
drawable=getResources().getDrawable(R.drawable.icon);
f.set(o,drawable);
Toast.makeText(this, f.getType().getName(), 1000).show();
} catch (Exception e) {
throw new RuntimeException(e);
}
这样就可以改变默认的滑块图片了。
源代码见：http://easymorse.googlecode.com/svn/tags/ListViewCustomerFastScroller-0.1/
http://marshal.easymorse.com/archives/3760
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：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: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];
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:UIViewAnimationTransitionCurlDown forView: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];
[UIView setAnimationTransition: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=[[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;
在翻页时的处理：
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];
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