<ImageSwitcher
  android:id="@+id/im"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_below="@+id/button1"
  android:layout_centerHorizontal="true"
  android:layout_marginTop="99dp" >
</ImageSwitcher>

<Button
  android:id="@+id/button1"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignParentTop="true"
  android:layout_centerHorizontal="true"
  android:layout_marginTop="77dp"
  android:text="上一张" />

<Button
  android:id="@+id/button2"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignLeft="@+id/button1"
  android:layout_below="@+id/im"
  android:layout_marginTop="51dp"
  android:text="下一张" />

package com.example.imageswitcher;

import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ViewSwitcher.ViewFactory;
import android.os.Build;

public class MainActivity extends Activity {
  private int[] imageId=new int[]{
      R.drawable.bj,   R.drawable.bj1, R.drawable.bj11,R.drawable.bj12
  };
  private int index=0;
  private ImageSwitcher imageSwitcher;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
   imageSwitcher=(ImageSwitcher) findViewById(R.id.im);  
   imageSwitcher.setInAnimation(this, android.R.anim.fade_in);//设置淡入的动画
   imageSwitcher.setOutAnimation(this ,android.R.anim.fade_out);//设置淡出的动画
   imageSwitcher.setFactory(new ViewFactory() {

    @Override
    public View makeView() {
      ImageView imageView=new ImageView(MainActivity.this);//创建一个Iv 的类
      imageView.setAdjustViewBounds(true);
      imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);//设置保持横纵比居中缩放图片
      imageView.setLayoutParams(new ImageSwitcher.LayoutParams(240,180));
      return imageView;
    }
  });
  imageSwitcher.setImageResource(imageId[index]);//显示默认的图片
  //获取两个按钮的ID
  Button up=(Button) findViewById(R.id.button1);
  Button down=(Button) findViewById(R.id.button2);

  up.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View v) {
    if(index>0){

      index--;

    }else{
      index =imageId.length-1;
    }
    imageSwitcher.setImageResource(imageId[index]);//显示当前的图片
    }
  });
  down.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View v) {
    if(index < imageId.length-1){
      index++;

    }else{
      index=0;

    }
    imageSwitcher.setImageResource(imageId[index]);//显示当前的图片
    }
  });

  }
}