Android实现幻灯片式图片浏览器

<?xml version="1.0" encoding="utf-8"?   
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
  android:orientation="vertical"  
  android:layout_width="fill_parent"  
  android:layout_height="fill_parent"  
  android:id="@+id/layout1" 
  android:gravity="center_horizontal" 
     
  <ImageSwitcher 
    android:id="@+id/imageSwitcher" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:paddingTop="30px" 
    android:layout_weight="2"/  
  <Gallery 
    android:id="@+id/gallery1" 
    android:spacing="5px" 
    android:layout_weight="1" 
    android:unselectedAlpha="0.6" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content"/  
</LinearLayout   

<?xml version="1.0" encoding="utf-8"?  
<resources  
  <declare-styleable name="Gallery"  
    <attr name="android:galleryItemBackground"/  
  </declare-styleable  
</resources  

package com.example.test;  
import android.app.Activity; 
import android.content.res.TypedArray; 
import android.os.Bundle; 
import android.view.View; 
import android.view.ViewGroup; 
import android.view.ViewGroup.LayoutParams; 
import android.view.animation.AnimationUtils; 
import android.widget.AdapterView; 
import android.widget.AdapterView.OnItemSelectedListener; 
import android.widget.BaseAdapter; 
import android.widget.Gallery; 
import android.widget.ImageSwitcher; 
import android.widget.ImageView; 
import android.widget.ViewSwitcher.ViewFactory; 
public class MainActivity extends Activity {  
//定义并初始化保存图片id的数组 
private int[] imageId=new int[]{R.drawable.img1,R.drawable.img2,R.drawable.img3,R.drawable.img4, 
R.drawable.img5,R.drawable.img6,R.drawable.img7,R.drawable.img8,R.drawable.img9}; 
//声明一个图像切换器对象 
private ImageSwitcher imageSwitcher; 
@Override  
public void onCreate(Bundle savedInstanceState) {  
super.onCreate(savedInstanceState);  
setContentView(R.layout.main);  
Gallery gallery=(Gallery)findViewById(R.id.gallery1);//获取gallery组件 
imageSwitcher=(ImageSwitcher)findViewById(R.id.imageSwitcher);//获取图像切换器 
//设置动画效果 
imageSwitcher.setInAnimation(AnimationUtils.loadAnimation(this, 
android.R.anim.fade_in));//设置淡入动画 
imageSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,  
android.R.anim.fade_out));//设置淡出动画 
imageSwitcher.setFactory(new ViewFactory(){ 
@Override 
public View makeView() { 
ImageView imageView=new ImageView(MainActivity.this);//实例化一个imageView类的对象 
imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);//设置保持纵横比居中缩放图像 
imageView.setLayoutParams(new ImageSwitcher.LayoutParams( 
LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT)); 
return imageView;//返回imageView对象 
} 
}); 
BaseAdapter adapter=new BaseAdapter(){ 
@Override 
public View getView(int position, View convertView, ViewGroup parent) { 
ImageView imageView;//声明ImageView的对象 
if(convertView==null){ 
imageView=new ImageView(MainActivity.this);//实例化ImageView的对象 
imageView.setScaleType(ImageView.ScaleType.FIT_XY);//设置缩放方式 
imageView.setLayoutParams(new Gallery.LayoutParams(180,135)); 
//设置gallery每一项图片的背景资源(使用的是attr.xml的自定义样式) 
TypedArray typedArray=obtainStyledAttributes(R.styleable.Gallery); 
imageView.setBackgroundResource(typedArray.getResourceId( 
R.styleable.Gallery_android_galleryItemBackground, 0)); 
imageView.setPadding(5, 0, 5, 0);//设置imageView的内边距 
}else{ 
imageView=(ImageView)convertView; 
} 
imageView.setImageResource(imageId[position]);//为imageView设置要显示的图片 
return imageView;//返回ImageView 
} 
//功能:获得当前选项的id 
@Override 
public long getItemId(int position) { 
return position; 
} 
//功能：获得当前选项 
@Override 
public Object getItem(int position) { 
return position; 
} 
//获得数量 
@Override 
public int getCount() { 
return imageId.length; 
} 
}; 
gallery.setAdapter(adapter);//将适配器与Gallery关联 
gallery.setSelection(imageId.length/2);//选中中间的图片 
gallery.setOnItemSelectedListener(new OnItemSelectedListener() { 
@Override 
public void onItemSelected(AdapterView<?  parent, View v, 
int position, long id) { 
imageSwitcher.setImageResource(imageId[position]);//显示选中的图片 
} 
@Override 
public void onNothingSelected(AdapterView<?  arg0) { 
// TODO Auto-generated method stub 
} 
}); 
}  
}