Android图片加载缓存框架Glide

public class MainActivity extends Activity {  private ImageView glide_iv;  private ListView glide_lv;  private static final String URL ="这里写图片url";  private List<String> urls = new ArrayList<String>();  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    initDatas();    glide_iv = (ImageView) findViewById(R.id.glide_iv);    // 通过下面这句代码把网络图片加载到ImageView中，非常方便    //Glide的with方法不仅接受Context，还接受Activity 和 Fragment等，Context会自动的从他们获取，使用很方便    Glide.with(this).load(URL).into(glide_iv);    glide_lv = (ListView) findViewById(R.id.glide_lv);    glide_lv.setAdapter(new BaseAdapter() {      @Override      public View getView(int arg0, View contentView, ViewGroup arg2) {        ViewHolder holder=null;        if (contentView == null) {          holder=new ViewHolder();          contentView= LayoutInflater.from(              MainActivity.this).inflate(R.layout.my_image_view,              null);          holder.itemIv = contentView.findViewById(R.id.item_iv);          contentView.setTag(holder);        } else {          holder=(ViewHolder) contentView.getTag();        }        String url = urls.get(arg0);        //在ListView中加载列表图片        Glide.with(MainActivity.this).load(url).centerCrop()            .placeholder(R.drawable.ic_launcher).crossFade()            .into(holder.itemIv);        return contentView;      }      @Override      public long getItemId(int arg0) {        // TODO Auto-generated method stub        return arg0;      }      @Override      public Object getItem(int arg0) {        // TODO Auto-generated method stub        return urls.get(arg0);      }      @Override      public int getCount() {        // TODO Auto-generated method stub        return urls.size();      }      class ViewHolder{        ImageView itemIv;      }    });  }  /**   * 添加数据   */  private void initDatas() {    for (int i = 0; i < 5; i++) {      urls.add(URL);    }  }}

<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:padding="20dp" >  <ImageView    android:id="@+id/glide_iv"    android:layout_width="80dp"    android:layout_height="80dp" />  <ListView    android:id="@+id/glide_lv"    android:layout_width="match_parent"    android:layout_height="wrap_content"     android:layout_below="@id/glide_iv">  </ListView></RelativeLayout>

<uses-permission android:name="android.permission.INTERNET" >