高性能加载器-在检查了这里建议的方法之后，我用了Ben的解决方案-

我意识到使用drawable比使用位图更快，所以我使用了drawable使用SoftReference很好，但它会使缓存的图像太频繁地被删除，所以我添加了一个保存图像引用的链接列表，防止图像被删除，直到达到预定义的大小为了打开InputStream，我使用java.net.URLConnection，它允许我使用web缓存（您需要先设置响应缓存，但这是另一回事）

我的代码：

import java.util.Map; 
import java.util.HashMap; 
import java.util.LinkedList; 
import java.util.Collections; 
import java.util.WeakHashMap; 
import java.lang.ref.SoftReference; 
import java.util.concurrent.Executors; 
import java.util.concurrent.ExecutorService; 
import android.graphics.drawable.Drawable;
import android.widget.ImageView;
import android.os.Handler;
import android.os.Message;
import java.io.InputStream;
import java.net.MalformedURLException; 
import java.io.IOException; 
import java.net.URL;
import java.net.URLConnection;

public class DrawableBackgroundDownloader {    

private final Map<String, SoftReference<Drawable>> mCache = new HashMap<String, SoftReference<Drawable>>();   
private final LinkedList <Drawable> mChacheController = new LinkedList <Drawable> ();
private ExecutorService mThreadPool;  
private final Map<ImageView, String> mImageViews = Collections.synchronizedMap(new WeakHashMap<ImageView, String>());  

public static int MAX_CACHE_SIZE = 80; 
public int THREAD_POOL_SIZE = 3;

/**
 * Constructor
 */
public DrawableBackgroundDownloader() {  
    mThreadPool = Executors.newFixedThreadPool(THREAD_POOL_SIZE);  
}  


/**
 * Clears all instance data and stops running threads
 */
public void Reset() {
    ExecutorService oldThreadPool = mThreadPool;
    mThreadPool = Executors.newFixedThreadPool(THREAD_POOL_SIZE);
    oldThreadPool.shutdownNow();

    mChacheController.clear();
    mCache.clear();
    mImageViews.clear();
}  

public void loadDrawable(final String url, final ImageView imageView,Drawable placeholder) {  
    mImageViews.put(imageView, url);  
    Drawable drawable = getDrawableFromCache(url);  

    // check in UI thread, so no concurrency issues  
    if (drawable != null) {  
        //Log.d(null, "Item loaded from mCache: " + url);  
        imageView.setImageDrawable(drawable);  
    } else {  
        imageView.setImageDrawable(placeholder);  
        queueJob(url, imageView, placeholder);  
    }  
} 


private Drawable getDrawableFromCache(String url) {  
    if (mCache.containsKey(url)) {  
        return mCache.get(url).get();  
    }  

    return null;  
}

private synchronized void putDrawableInCache(String url,Drawable drawable) {  
    int chacheControllerSize = mChacheController.size();
    if (chacheControllerSize > MAX_CACHE_SIZE) 
        mChacheController.subList(0, MAX_CACHE_SIZE/2).clear();

    mChacheController.addLast(drawable);
    mCache.put(url, new SoftReference<Drawable>(drawable));

}  

private void queueJob(final String url, final ImageView imageView,final Drawable placeholder) {  
    /* Create handler in UI thread. */  
    final Handler handler = new Handler() {  
        @Override  
        public void handleMessage(Message msg) {  
            String tag = mImageViews.get(imageView);  
            if (tag != null && tag.equals(url)) {
                if (imageView.isShown())
                    if (msg.obj != null) {
                        imageView.setImageDrawable((Drawable) msg.obj);  
                    } else {  
                        imageView.setImageDrawable(placeholder);  
                        //Log.d(null, "fail " + url);  
                    } 
            }  
        }  
    };  

    mThreadPool.submit(new Runnable() {  
        @Override  
        public void run() {  
            final Drawable bmp = downloadDrawable(url);
            // if the view is not visible anymore, the image will be ready for next time in cache
            if (imageView.isShown())
            {
                Message message = Message.obtain();  
                message.obj = bmp;
                //Log.d(null, "Item downloaded: " + url);  

                handler.sendMessage(message);
            }
        }  
    });  
}  



private Drawable downloadDrawable(String url) {  
    try {  
        InputStream is = getInputStream(url);

        Drawable drawable = Drawable.createFromStream(is, url);
        putDrawableInCache(url,drawable);  
        return drawable;  

    } catch (MalformedURLException e) {  
        e.printStackTrace();  
    } catch (IOException e) {  
        e.printStackTrace();  
    }  

    return null;  
}  


private InputStream getInputStream(String urlString) throws MalformedURLException, IOException {
    URL url = new URL(urlString);
    URLConnection connection;
    connection = url.openConnection();
    connection.setUseCaches(true); 
    connection.connect();
    InputStream response = connection.getInputStream();

    return response;
}
}

更新：请注意，这个答案现在非常无效。垃圾回收器对SoftReference和WeakReference进行攻击，因此此代码不适用于新应用。（相反，请尝试其他答案中建议的通用图像加载器之类的库。）

感谢James提供的代码，感谢鲍龙提供的使用SoftReference的建议。我在James的代码上实现了SoftReference更改。不幸的是，SoftReferences导致我的图像被垃圾收集得太快。在我的情况下，没有SoftReference的东西很好，因为我的列表大小有限，图像也很小。

一年前有一场关于谷歌群组上SoftReferences的讨论：链接到线程。作为过早垃圾收集的解决方案，他们建议使用dalvik.system.VMRuntime.setMinimumHeapSize（）手动设置VM堆大小，这对我来说不是很有吸引力。

public DrawableManager() {
    drawableMap = new HashMap<String, SoftReference<Drawable>>();
}

public Drawable fetchDrawable(String urlString) {
    SoftReference<Drawable> drawableRef = drawableMap.get(urlString);
    if (drawableRef != null) {
        Drawable drawable = drawableRef.get();
        if (drawable != null)
            return drawable;
        // Reference has expired so remove the key from drawableMap
        drawableMap.remove(urlString);
    }

    if (Constants.LOGGING) Log.d(this.getClass().getSimpleName(), "image url:" + urlString);
    try {
        InputStream is = fetch(urlString);
        Drawable drawable = Drawable.createFromStream(is, "src");
        drawableRef = new SoftReference<Drawable>(drawable);
        drawableMap.put(urlString, drawableRef);
        if (Constants.LOGGING) Log.d(this.getClass().getSimpleName(), "got a thumbnail drawable: " + drawable.getBounds() + ", "
                + drawable.getIntrinsicHeight() + "," + drawable.getIntrinsicWidth() + ", "
                + drawable.getMinimumHeight() + "," + drawable.getMinimumWidth());
        return drawableRef.get();
    } catch (MalformedURLException e) {
        if (Constants.LOGGING) Log.e(this.getClass().getSimpleName(), "fetchDrawable failed", e);
        return null;
    } catch (IOException e) {
        if (Constants.LOGGING) Log.e(this.getClass().getSimpleName(), "fetchDrawable failed", e);
        return null;
    }
}

public void fetchDrawableOnThread(final String urlString, final ImageView imageView) {
    SoftReference<Drawable> drawableRef = drawableMap.get(urlString);
    if (drawableRef != null) {
        Drawable drawable = drawableRef.get();
        if (drawable != null) {
            imageView.setImageDrawable(drawableRef.get());
            return;
        }
        // Reference has expired so remove the key from drawableMap
        drawableMap.remove(urlString);
    }

    final Handler handler = new Handler() {
        @Override
        public void handleMessage(Message message) {
            imageView.setImageDrawable((Drawable) message.obj);
        }
    };

    Thread thread = new Thread() {
        @Override
        public void run() {
            //TODO : set imageView to a "pending" image
            Drawable drawable = fetchDrawable(urlString);
            Message message = handler.obtainMessage(1, drawable);
            handler.sendMessage(message);
        }
    };
    thread.start();
}

我建议使用开源仪器Universal Image Loader。它最初基于Fedor Vlasov的项目LazyList，此后得到了极大的改进。

多线程图像加载可以广泛调整ImageLoader的配置（线程执行器、下载器、解码器、内存和磁盘缓存、显示图像选项等）可以在内存和/或设备的文件系统（或SD卡）中缓存图像“聆听”加载过程的可能性可以使用单独的选项自定义每个显示图像通话小工具支持Android 2.0+支持

如果你想像Facebook一样显示Shimmer布局，有一个官方的Facebook库。FaceBook Shimmer Android

它可以处理所有的事情，你只需要将你想要的设计代码以嵌套的方式放在闪闪发光的框架中。这是一个示例代码。

<com.facebook.shimmer.ShimmerFrameLayout
     android:id=“@+id/shimmer_view_container”
     android:layout_width=“wrap_content”
     android:layout_height="wrap_content"
     shimmer:duration="1000">

 <here will be your content to display />

</com.facebook.shimmer.ShimmerFrameLayout>

这是它的java代码。

ShimmerFrameLayout shimmerContainer = (ShimmerFrameLayout) findViewById(R.id.shimmer_view_container);
shimmerContainer.startShimmerAnimation();

在渐变文件中添加此相关性。

implementation 'com.facebook.shimmer:shimmer:0.1.0@aar'

这是它的样子。

使用滑动库。它适用于我，也适用于你的代码。它也适用于图像和gif。

ImageView imageView = (ImageView) findViewById(R.id.test_image); 
    GlideDrawableImageViewTarget imagePreview = new GlideDrawableImageViewTarget(imageView);
    Glide
            .with(this)
            .load(url)
            .listener(new RequestListener<String, GlideDrawable>() {
                @Override
                public boolean onException(Exception e, String model, Target<GlideDrawable> target, boolean isFirstResource) {                       
                    return false;
                }

                @Override
                public boolean onResourceReady(GlideDrawable resource, String model, Target<GlideDrawable> target, boolean isFromMemoryCache, boolean isFirstResource) {
                    return false;
                }
            })
            .into(imagePreview);
}

我遇到了这个问题，并实现了lruCache。我相信你需要API 12或更高版本，或者使用兼容的v4库。lurCache是快速内存，但它也有预算，所以如果你担心，你可以使用磁盘缓存。。。这都在缓存位图中描述。

现在我将提供我的实现，它是我从任何地方调用的单例，如下所示：

//Where the first is a string and the other is a imageview to load.

DownloadImageTask.getInstance().loadBitmap(avatarURL, iv_avatar);

以下是理想的代码，在检索web图像时，缓存并在适配器的getView中调用上述代码：

public class DownloadImageTask {

    private LruCache<String, Bitmap> mMemoryCache;

    /* Create a singleton class to call this from multiple classes */

    private static DownloadImageTask instance = null;

    public static DownloadImageTask getInstance() {
        if (instance == null) {
            instance = new DownloadImageTask();
        }
        return instance;
    }

    //Lock the constructor from public instances
    private DownloadImageTask() {

        // Get max available VM memory, exceeding this amount will throw an
        // OutOfMemory exception. Stored in kilobytes as LruCache takes an
        // int in its constructor.
        final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);

        // Use 1/8th of the available memory for this memory cache.
        final int cacheSize = maxMemory / 8;

        mMemoryCache = new LruCache<String, Bitmap>(cacheSize) {
            @Override
            protected int sizeOf(String key, Bitmap bitmap) {
                // The cache size will be measured in kilobytes rather than
                // number of items.
                return bitmap.getByteCount() / 1024;
            }
        };
    }

    public void loadBitmap(String avatarURL, ImageView imageView) {
        final String imageKey = String.valueOf(avatarURL);

        final Bitmap bitmap = getBitmapFromMemCache(imageKey);
        if (bitmap != null) {
            imageView.setImageBitmap(bitmap);
        } else {
            imageView.setImageResource(R.drawable.ic_launcher);

            new DownloadImageTaskViaWeb(imageView).execute(avatarURL);
        }
    }

    private void addBitmapToMemoryCache(String key, Bitmap bitmap) {
        if (getBitmapFromMemCache(key) == null) {
            mMemoryCache.put(key, bitmap);
        }
    }

    private Bitmap getBitmapFromMemCache(String key) {
        return mMemoryCache.get(key);
    }

    /* A background process that opens a http stream and decodes a web image. */

    class DownloadImageTaskViaWeb extends AsyncTask<String, Void, Bitmap> {
        ImageView bmImage;

        public DownloadImageTaskViaWeb(ImageView bmImage) {
            this.bmImage = bmImage;
        }

        protected Bitmap doInBackground(String... urls) {

            String urldisplay = urls[0];
            Bitmap mIcon = null;
            try {
                InputStream in = new java.net.URL(urldisplay).openStream();
                mIcon = BitmapFactory.decodeStream(in);

            } 
            catch (Exception e) {
                Log.e("Error", e.getMessage());
                e.printStackTrace();
            }

            addBitmapToMemoryCache(String.valueOf(urldisplay), mIcon);

            return mIcon;
        }

        /* After decoding we update the view on the main UI. */
        protected void onPostExecute(Bitmap result) {
            bmImage.setImageBitmap(result);
        }
    }
}