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。

我发现滑翔机比毕加索更好。我使用picasso加载了大约32张图片，每张图片的大小约为200-500KB，而且我总是得到OOM。但滑翔机解决了我所有的OOM问题。

检查我的懒惰列表。基本上，我通过延迟ImageView的调用来改进LazyList，并创建两个方法：

当您需要放置类似“正在加载图像…”的内容时当您需要显示下载的图像时。

我还通过在这个对象中实现一个单例来改进ImageLoader。

public class ImageDownloader {

Map<String, Bitmap> imageCache;

public ImageDownloader() {
    imageCache = new HashMap<String, Bitmap>();

}

// download function
public void download(String url, ImageView imageView) {
    if (cancelPotentialDownload(url, imageView)) {

        // Caching code right here
        String filename = String.valueOf(url.hashCode());
        File f = new File(getCacheDirectory(imageView.getContext()),
                filename);

        // Is the bitmap in our memory cache?
        Bitmap bitmap = null;

        bitmap = (Bitmap) imageCache.get(f.getPath());

        if (bitmap == null) {

            bitmap = BitmapFactory.decodeFile(f.getPath());

            if (bitmap != null) {
                imageCache.put(f.getPath(), bitmap);
            }

        }
        // No? download it
        if (bitmap == null) {
            try {
                BitmapDownloaderTask task = new BitmapDownloaderTask(
                        imageView);
                DownloadedDrawable downloadedDrawable = new DownloadedDrawable(
                        task);
                imageView.setImageDrawable(downloadedDrawable);
                task.execute(url);
            } catch (Exception e) {
                Log.e("Error==>", e.toString());
            }

        } else {
            // Yes? set the image
            imageView.setImageBitmap(bitmap);
        }
    }
}

// cancel a download (internal only)
private static boolean cancelPotentialDownload(String url,
        ImageView imageView) {
    BitmapDownloaderTask bitmapDownloaderTask = getBitmapDownloaderTask(imageView);

    if (bitmapDownloaderTask != null) {
        String bitmapUrl = bitmapDownloaderTask.url;
        if ((bitmapUrl == null) || (!bitmapUrl.equals(url))) {
            bitmapDownloaderTask.cancel(true);
        } else {
            // The same URL is already being downloaded.
            return false;
        }
    }
    return true;
}

// gets an existing download if one exists for the imageview
private static BitmapDownloaderTask getBitmapDownloaderTask(
        ImageView imageView) {
    if (imageView != null) {
        Drawable drawable = imageView.getDrawable();
        if (drawable instanceof DownloadedDrawable) {
            DownloadedDrawable downloadedDrawable = (DownloadedDrawable) drawable;
            return downloadedDrawable.getBitmapDownloaderTask();
        }
    }
    return null;
}

// our caching functions
// Find the dir to save cached images
private static File getCacheDirectory(Context context) {
    String sdState = android.os.Environment.getExternalStorageState();
    File cacheDir;

    if (sdState.equals(android.os.Environment.MEDIA_MOUNTED)) {
        File sdDir = android.os.Environment.getExternalStorageDirectory();

        // TODO : Change your diretcory here
        cacheDir = new File(sdDir, "data/ToDo/images");
    } else
        cacheDir = context.getCacheDir();

    if (!cacheDir.exists())
        cacheDir.mkdirs();
    return cacheDir;
}

private void writeFile(Bitmap bmp, File f) {
    FileOutputStream out = null;

    try {
        out = new FileOutputStream(f);
        bmp.compress(Bitmap.CompressFormat.PNG, 80, out);
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            if (out != null)
                out.close();
        } catch (Exception ex) {
        }
    }
}

// download asynctask
public class BitmapDownloaderTask extends AsyncTask<String, Void, Bitmap> {
    private String url;
    private final WeakReference<ImageView> imageViewReference;

    public BitmapDownloaderTask(ImageView imageView) {
        imageViewReference = new WeakReference<ImageView>(imageView);
    }

    @Override
    // Actual download method, run in the task thread
    protected Bitmap doInBackground(String... params) {
        // params comes from the execute() call: params[0] is the url.
        url = (String) params[0];
        return downloadBitmap(params[0]);
    }

    @Override
    // Once the image is downloaded, associates it to the imageView
    protected void onPostExecute(Bitmap bitmap) {
        if (isCancelled()) {
            bitmap = null;
        }

        if (imageViewReference != null) {
            ImageView imageView = imageViewReference.get();
            BitmapDownloaderTask bitmapDownloaderTask = getBitmapDownloaderTask(imageView);
            // Change bitmap only if this process is still associated with
            // it
            if (this == bitmapDownloaderTask) {
                imageView.setImageBitmap(bitmap);

                // cache the image

                String filename = String.valueOf(url.hashCode());
                File f = new File(
                        getCacheDirectory(imageView.getContext()), filename);

                imageCache.put(f.getPath(), bitmap);

                writeFile(bitmap, f);
            }
        }
    }

}

static class DownloadedDrawable extends ColorDrawable {
    private final WeakReference<BitmapDownloaderTask> bitmapDownloaderTaskReference;

    public DownloadedDrawable(BitmapDownloaderTask bitmapDownloaderTask) {
        super(Color.WHITE);
        bitmapDownloaderTaskReference = new WeakReference<BitmapDownloaderTask>(
                bitmapDownloaderTask);
    }

    public BitmapDownloaderTask getBitmapDownloaderTask() {
        return bitmapDownloaderTaskReference.get();
    }
}

// the actual download code
static Bitmap downloadBitmap(String url) {
    HttpParams params = new BasicHttpParams();
    params.setParameter(CoreProtocolPNames.PROTOCOL_VERSION,
            HttpVersion.HTTP_1_1);
    HttpClient client = new DefaultHttpClient(params);
    final HttpGet getRequest = new HttpGet(url);

    try {
        HttpResponse response = client.execute(getRequest);
        final int statusCode = response.getStatusLine().getStatusCode();
        if (statusCode != HttpStatus.SC_OK) {
            Log.w("ImageDownloader", "Error " + statusCode
                    + " while retrieving bitmap from " + url);
            return null;
        }

        final HttpEntity entity = response.getEntity();
        if (entity != null) {
            InputStream inputStream = null;
            try {
                inputStream = entity.getContent();
                final Bitmap bitmap = BitmapFactory
                        .decodeStream(inputStream);
                return bitmap;
            } finally {
                if (inputStream != null) {
                    inputStream.close();
                }
                entity.consumeContent();
            }
        }
    } catch (Exception e) {
        // Could provide a more explicit error message for IOException or
        // IllegalStateException
        getRequest.abort();
        Log.w("ImageDownloader", "Error while retrieving bitmap from "
                + url + e.toString());
    } finally {
        if (client != null) {
            // client.close();
        }
    }
    return null;
 }
}

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();
}

嗯，从互联网加载图像有很多解决方案。您也可以使用Android Query库。它将为您提供所有必需的活动。确保您想做什么，并阅读库wiki页面。并解决了图像加载限制。

这是我的代码：

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View v = convertView;
    if (v == null) {
        LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        v = vi.inflate(R.layout.row, null);
    }

    ImageView imageview = (ImageView) v.findViewById(R.id.icon);
    AQuery aq = new AQuery(convertView);

    String imageUrl = "http://www.vikispot.com/z/images/vikispot/android-w.png";

    aq.id(imageview).progress(this).image(imageUrl, true, true, 0, 0, new BitmapAjaxCallback() {
        @Override
        public void callback(String url, ImageView iv, Bitmap bm, AjaxStatus status) {
            iv.setImageBitmap(bm);
        }
    ));

    return v;
}

它应该可以解决您的延迟加载问题。