ImageLoader

compile 'com.nostra13.universalimageloader:universal-image-loader:1.9.5'

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    implementation 'com.android.support:support-v4:26.1.0'
    implementation 'com.android.support:recyclerview-v7:26.1.0'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.1'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
    compile 'org.greenrobot:greendao:3.2.2'
    compile 'com.nostra13.universalimageloader:universal-image-loader:1.9.5'
}

public class MyApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
       initImageLoader();
    }
    public void initImageLoader(){

        ImageLoaderConfiguration.Builder config = new ImageLoaderConfiguration.Builder(getApplicationContext());

        config.threadPriority(Thread.NORM_PRIORITY - 2);
        config.denyCacheImageMultipleSizesInMemory();

        config.diskCacheFileNameGenerator(new Md5FileNameGenerator());
        config.diskCacheSize(50*1024*1024);
        config.tasksProcessingOrder(QueueProcessingType.LIFO);
        config.writeDebugLogs();
        ImageLoader.getInstance().init(config.build());
    }
}

<application
    android:name=".MyApplication"
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">

</application>

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

public class MyImageListActivity extends Activity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.fr_image_list);
        ListView listView = findViewById(R.id.listview);
        listView.setAdapter(new ImageAdapter());
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener(){
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                Log.i("test","click "+i);
            }
        });
    }
    @Override
    protected void onDestroy() {
        //回收缓存在内存中的图片
        ImageLoader.getInstance().clearMemoryCache();
        super.onDestroy();
    }

    private class ImageAdapter extends BaseAdapter{

        private String[] IMAGES_URI = new String[]{
                "http://mowin.org/wp-content/uploads/2017/07/arborists-forestry.jpg",
                "http://s1.1zoom.me/big0/506/Sky_Grasslands_Rainbow_502473.jpg",
                 };
        // 创建DisplayImageOptions对象
        private DisplayImageOptions options;

        public ImageAdapter() {
            options = new DisplayImageOptions.Builder()
                    .showImageOnLoading(R.drawable.dog)  // 下载期间显示的图片
                    .showImageForEmptyUri(R.drawable.dog)//Uri为空或是错误的时候显示的图片
                    .showImageOnFail(R.drawable.ic_launcher_background)//发生错误显示的图片
                    .cacheInMemory(true)//载的图片是否缓存在内存中
                    .cacheOnDisk(true)//载的图片是否缓存在sdcard中
                    .considerExifParams(true)
                    .displayer(new CircleBitmapDisplayer(Color.WHITE,5))//图片
                    .build();
        }

        @Override
        public int getCount() {
            return IMAGES_URI.length;
        }

        @Override
        public Object getItem(int i) {
            return IMAGES_URI[i];
        }

        @Override
        public long getItemId(int i) {
            return i;
        }

        @Override
        public View getView(int i, View view, ViewGroup viewGroup) {
            ViewHolder holder;
            if(view == null){
                holder = new ViewHolder();
                view = LayoutInflater.from(MyImageListActivity.this).inflate(R.layout.item_list_image,null);
                holder.imageView = (ImageView)view.findViewById(R.id.item_image);
                holder.textView = (TextView)view.findViewById(R.id.item_name);
                view.setTag(holder);
            }else{
                holder = (ViewHolder)view.getTag();
            }
            holder.textView.setText("Item " + (i + 1));
            //
            ImageLoader.getInstance().displayImage(IMAGES_URI[i],holder.imageView,options);
            return view;
        }
    }

    static  class ViewHolder{
        ImageView imageView;
        TextView textView;

    }
}

"http://site.com/image.png" // from Web
"file:///mnt/sdcard/image.png" // from SD card
"file:///mnt/sdcard/video.mp4" // from SD card (video thumbnail)
"content://media/external/images/media/13" // from content provider
"content://media/external/video/media/13" // from content provider (video thumbnail)
"assets://image.png" // from assets
"drawable://" + R.drawable.img // from drawables (non-9patch images)

设置图片的显示方式

displayer(BitmapDisplayer displayer) 

  SimpleBitmapDisplayer() //默认 正常显示一张图片

  CircleBitmapDisplayer(Color.WHITE,5)//圆形图片

  RoundedBitmapDisplayer(20) //圆角图片，弧度20. 不推荐用

  FadeInBitmapDisplayer(100)//加载图片后渐入的时间
  FakeBitmapDisplayer()
图片压缩质量参数
bitmapConfig(Bitmap.Config.RGB_565)
在android中的大图片一般都要经过压缩才能显示，不然容易发生oom，影响一个图片占用空间的有尺寸大小 色彩细节。

public static final Bitmap.Config ALPHA_8  
public static final Bitmap.Config ARGB_4444  
public static final Bitmap.Config ARGB_8888  
public static final Bitmap.Config RGB_565