Android UI控件之ImageSwitcher实现图片切换效果

package com.kiritor.ui_imageswitcher; 
 
import android.app.Activity; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.ImageSwitcher; 
import android.widget.ImageView; 
import android.widget.ViewSwitcher.ViewFactory; 
/*注意，此处直接让该类实现ViewFactory和OnClickListener接口*/ 
public class MainActivity extends Activity implements ViewFactory, OnClickListener { 
   /*获取图片资源集*/ 
   private static final Integer[] images = { 
      R.drawable.first, 
      R.drawable.second, 
      R.drawable.third, 
       
   }; 
    
   private ImageSwitcher is; 
   private Button btnPrev,btnNext; 
   private static int index = 0; 
  /** Called when the activity is first created. */ 
  @Override 
  public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    /*通过ID获取控件*/ 
    is = (ImageSwitcher) findViewById(R.id.image_switchter); 
    btnPrev = (Button) findViewById(R.id.pre); 
    btnNext = (Button) findViewById(R.id.next); 
    
    is.setFactory(this);//设置ImageSwitcher所需的ViewFactory 
    is.setImageResource(images[index]);//设置初始的图片资源 
    /*由于本类实现了OnClickListen而接口，所以这里参数可以直接用this*/ 
    btnPrev.setOnClickListener(this); 
    btnNext.setOnClickListener(this); 
  } 
  /*因为实现了接口，需要实现接口中未实现的方法*/ 
   public void onClick(View v) { 
      switch(v.getId()){ 
      case R.id.next: 
         index++; 
         if(index>=images.length){ 
           index = 0; 
         } 
         is.setImageResource(images[index]); 
         break; 
      case R.id.pre: 
         index--; 
         if(index<0){ 
           index = images.length - 1; 
         } 
         is.setImageResource(images[index]); 
         break; 
      default: 
         break; 
      } 
   } 
   /** 
    * 该方法返回一个View的实例 
    * 这个实例就是要在ImageSwitcher中所显示的 
    * 此处就用ImageView来显示内容 
    * 所以直接返回一个新的ImageView的实例 
    */ 
   public View makeView() { 
      return new ImageView(this); 
   } 
}