imageLoader加载图片配置

最新推荐文章于 2018-11-07 16:51:22 发布

原创最新推荐文章于 2018-11-07 16:51:22 发布 · 408 阅读

1 ·

CC 4.0 BY-SA版权

本文介绍了一种在Android应用中使用ImageLoader从网络加载图片到ListView的方法。通过自定义适配器，实现图片的缓存及加载，提高用户体验。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

//Activity布局

//list_item布局

//Activity

public class MainActivity extends Activity {

private ListView lv;

//最好是自己多找一些图片
String[]paths=new String[]{
   "http://pic42.nipic.com/20140607/18358876_140318247306_2.jpg",
   "http://pic1.nipic.com/2008-12-25/2008122510134038_2.jpg",
   "http://img1.3lian.com/2015/w7/98/d/22.jpg",
   "http://img1.3lian.com/2015/w7/98/d/1.jpg",
   "http://img1.3lian.com/2015/w7/98/d/2.jpg",
   "http://img1.3lian.com/2015/w7/98/d/3.jpg",};

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        lv=(ListView) findViewById(R.id.listView);
        lv.setAdapter(new MyAdapter(this,paths));
    }

//MyAdapter

public class MyAdapter extends BaseAdapter {

private final Context context;
private final String[] paths;
private ImageLoader imageLoader;
private DisplayImageOptions.Builder builder;

public MyAdapter(Context context, String[] paths) {
  this.context = context;
  // TODO Auto-generated constructor stub
  this.paths = paths;
  imageLoader = ImageLoader.getInstance();
  //加载图片的过程中，对图片的设置
  builder = new Builder();
  //图片是否缓存在内存中
  builder.cacheInMemory(true);
  //图片是否缓存在sd卡中
  builder.cacheOnDisk(true);

  //图片的地址为空的时候显示的默认图片
  builder.showImageForEmptyUri(R.drawable.ic_launcher);
  //图片加载失败显示的默认图片
  builder.showImageOnFail(R.drawable.ic_launcher);
  //图片加载过程中显示的图片
  builder.showImageOnLoading(R.drawable.ic_launcher);
  //每个像素点占16位
  builder.bitmapConfig(Config.RGB_565);




}

@Override
public int getCount() {
// TODO Auto-generated method stub
return paths.length;
}

@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}

@Override
public long getItemId(int position) {
  // TODO Auto-generated method stub
  return 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
  ViewHolder holder;
  if(convertView==null){
   holder = new ViewHolder();
   convertView=View.inflate(context, R.layout.list_item, null);
   holder.iv=(ImageView) convertView.findViewById(R.id.imageView);
   convertView.setTag(holder);
  }else{
   holder=(ViewHolder) convertView.getTag();

  }

  //参数一：图片地址
  //参数二：展示图片的控件
  //参数三：加载图片过程中设置的属性
  //参数四：加载图片过程中的监听
  imageLoader.displayImage(paths[position], holder.iv, builder.build(),new ImageLoadingListener() {

   //开始加载图片
   @Override
   public void onLoadingStarted(String arg0, View arg1) {
    // TODO Auto-generated method stub

   }

   //图片加载失败
   @Override
   public void onLoadingFailed(String arg0, View arg1, FailReason arg2) {


   }

   //图片加载成功
   @Override
   public void onLoadingComplete(String arg0, View arg1, Bitmap arg2) {
    // TODO Auto-generated method stub

   }

   //图片取消加载
   @Override
   public void onLoadingCancelled(String arg0, View arg1) {
    // TODO Auto-generated method stub

   }
  });


  return convertView;
}
class ViewHolder{
  private ImageView iv;
}

}

//创建一个类 MyApplication 继承Application

public class MyApplication extends Application{

@Override
public void onCreate() {
  // TODO Auto-generated method stub
  super.onCreate();

  //初始化imageloader
  setImageloader();
}

private void setImageloader() {
  //得到imageLoader
  ImageLoader imageLoader = ImageLoader.getInstance();
  //imageLoader构建对象
  ImageLoaderConfiguration.Builder builder=new Builder(this);
  //设置磁盘缓存策略(sd卡)
  String cacheDir=Environment.getExternalStorageDirectory()+"/ImagaloadercacheDir";
  //磁盘缓存
  builder.discCache(new UnlimitedDiskCache(new File(cacheDir)));
  //内存缓存
  builder.memoryCache(new LruMemoryCache(1024*1024*20));

  imageLoader.init(builder.build());

}

}