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

以下是我创建的用于保存应用程序当前显示的图像的内容。请注意，这里使用的“Log”对象是我对Android中最终Log类的自定义包装。

package com.wilson.android.library;

/*
 Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License.  You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied.  See the License for the
specific language governing permissions and limitations
under the License.
*/
import java.io.IOException;

public class DrawableManager {
    private final Map<String, Drawable> drawableMap;

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

    public Drawable fetchDrawable(String urlString) {
        if (drawableMap.containsKey(urlString)) {
            return drawableMap.get(urlString);
        }

        Log.d(this.getClass().getSimpleName(), "image url:" + urlString);
        try {
            InputStream is = fetch(urlString);
            Drawable drawable = Drawable.createFromStream(is, "src");


            if (drawable != null) {
                drawableMap.put(urlString, drawable);
                Log.d(this.getClass().getSimpleName(), "got a thumbnail drawable: " + drawable.getBounds() + ", "
                        + drawable.getIntrinsicHeight() + "," + drawable.getIntrinsicWidth() + ", "
                        + drawable.getMinimumHeight() + "," + drawable.getMinimumWidth());
            } else {
              Log.w(this.getClass().getSimpleName(), "could not get thumbnail");
            }

            return drawable;
        } catch (MalformedURLException e) {
            Log.e(this.getClass().getSimpleName(), "fetchDrawable failed", e);
            return null;
        } catch (IOException e) {
            Log.e(this.getClass().getSimpleName(), "fetchDrawable failed", e);
            return null;
        }
    }

    public void fetchDrawableOnThread(final String urlString, final ImageView imageView) {
        if (drawableMap.containsKey(urlString)) {
            imageView.setImageDrawable(drawableMap.get(urlString));
        }

        final Handler handler = new Handler(Looper.getMainLooper()) {
            @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();
    }

    private InputStream fetch(String urlString) throws MalformedURLException, IOException {
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpGet request = new HttpGet(urlString);
        HttpResponse response = httpClient.execute(request);
        return response.getEntity().getContent();
    }
}

一些答案已经提到了使用各种图像库，如通用图像加载器和androidimageloader等。这是一个老问题，但对于仍在寻找类似内容的人来说，有几个这样的库用于图像加载/缓存。

我已经关注了这个Android培训，我认为它在下载图像而不阻塞主UI方面做得很好。它还处理缓存和滚动许多图像：高效加载大型位图

我使用droidQuery。从URL加载图像有两种机制。第一个（速记）简单地是：

$.with(myView).image(url);

这可以很容易地添加到ArrayAdapter的getView（…）方法中。

longhand方法将提供更多的控制，并具有此处未讨论的选项（如缓存和回调），但可以在此处找到将输出大小指定为200px x 200px的基本实现：

$.ajax(new AjaxOptions().url(url)
    .type("GET")
    .dataType("image")
    .imageWidth(200).imageHeight(200)
    .success(new Function() {
        @Override
        public void invoke($ droidQuery, Object... params) {
            myImageView.setImageBitmap((Bitmap) params[0]);
        }
    })
    .error(new Function() {
        @Override
        public void invoke($ droidQuery, Object... params) {
            AjaxError e = (AjaxError) params[0];
            Log.e("$", "Error " + e.status + ": " + e.error);
        }
    })
);

我只想再添加一个很好的示例，XML适配器。由于它被谷歌使用，我也在使用相同的逻辑来避免OutOfMemory错误。

基本上，这个ImageDownloader就是你的答案（因为它涵盖了你的大部分需求）。有些也可以在其中实现。