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);    } }