Android实现自动播放图片功能 Android实现自动播放图片功能

package com.example.week4_day4_viewpager2; 
 
import java.util.ArrayList; 
import java.util.List; 
 
import android.R.integer; 
import android.os.Bundle; 
import android.os.Handler; 
import android.app.Activity; 
import android.support.v4.view.ViewPager; 
import android.view.Menu; 
import android.widget.ImageView; 
 
public class MainActivity extends Activity { 
 
  private ViewPager viewPager; 
  // 数据源 
  private int[] images = { R.drawable.image1, R.drawable.image2, 
      R.drawable.image3 }; 
  // 存放数据源的集合 
  List<ImageView> list; 
 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    viewPager = (ViewPager) findViewById(R.id.viewpager); 
    // 实例化list 
    list = new ArrayList<ImageView>(); 
    for (int i = 0; i < images.length; i++) { 
      ImageView imageView = new ImageView(MainActivity.this); 
      imageView.setImageResource(images[i]); 
      list.add(imageView); 
    } 
    // 绑定适配器 
    viewPager.setAdapter(new MyViewPagerAdapter(MainActivity.this, list)); 
    // 当有3张图片时,走到id=2时最后一张, 
    viewPager.setCurrentItem(Integer.MAX_VALUE / 2 - Integer.MAX_VALUE / 2 
        % list.size());// 假设viewPager有无数条数据 
    // 延迟两秒发送一条消息 
    handler.sendEmptyMessageDelayed(1, 2000); 
  } 
 
  // 让图片自动播放,无限循环 
  private Handler handler = new Handler() { 
    public void handleMessage(android.os.Message msg) { 
      /** 
       * 第一种方法,播放到最后一张时,回退到第一张照片从头播放 
       *       弊端:回退时如果图片过多,会出现回退重影,即3张时,从最后一张瞬间回退到第2张,又瞬间回退到第1张 
       */ 
//      int i = viewPager.getCurrentItem();// 当前item 
//      if (i == list.size() - 1) {// 如果第一条等于最后一条 
//      // false:是否显示动画 
//      viewPager.setCurrentItem(0, true);// 回到第一条item 
//      } else { 
//      viewPager.setCurrentItem(i + 1, true); 
//      } 
      /** 
       * 第二种方法,无限循环播放,每次都把所有相片,放到后面查看 
       */ 
      viewPager.setCurrentItem(viewPager.getCurrentItem() + 1); 
 
      sendEmptyMessageDelayed(1, 2000); 
    }; 
  }; 
} 

package com.example.week4_day4_viewpager2; 
 
import java.util.List; 
 
import android.content.Context; 
import android.support.v4.view.PagerAdapter; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.ImageView; 
 
public class MyViewPagerAdapter extends PagerAdapter{ 
 
  private Context context; 
  private List<ImageView> list; 
   
  public MyViewPagerAdapter(Context context, List<ImageView> list) { 
    super(); 
    this.context = context; 
    this.list = list; 
  } 
 
  @Override 
  public int getCount() { 
    // TODO Auto-generated method stub 
    return Integer.MAX_VALUE;//设置viewPager里有N条数据 
    //return list.size(); 
  } 
   
  @Override 
  public Object instantiateItem(ViewGroup container, int position) { 
    //假设有3张照片,走到id=2时,走id=0的,所以取余 
    container.addView(list.get(position%list.size())); 
    return list.get(position%list.size()); 
    //return list.get(position); 
  } 
  @Override 
  public void destroyItem(ViewGroup container, int position, Object object) { 
    // TODO Auto-generated method stub 
    container.removeView(list.get(position%list.size())); 
    //container.removeView(list.get(position)); 
    //super.destroyItem(container, position, object); 
  } 
 
  @Override 
  public boolean isViewFromObject(View arg0, Object arg1) { 
    // TODO Auto-generated method stub 
    return arg0==arg1; 
  } 
 
}  

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
  xmlns:tools="http://schemas.android.com/tools" 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  android:paddingBottom="@dimen/activity_vertical_margin" 
  android:paddingLeft="@dimen/activity_horizontal_margin" 
  android:paddingRight="@dimen/activity_horizontal_margin" 
  android:paddingTop="@dimen/activity_vertical_margin" 
  tools:context=".MainActivity" > 
 
  <android.support.v4.view.ViewPager 
    android:id="@+id/viewpager" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
   /> 
 
</RelativeLayout>