我正在开发一个应用程序，其中我为幻灯片放映异步下载图像。一个 SlideShow 包含 10 张幻灯片，因此打开幻灯片时会下载 10 张图像。在我大约滚动 10-15 个幻灯片后，我开始收到内存警告，跟踪中出现异常，应用程序崩溃。

这是痕迹:

12-23 12:23:53.124: ERROR/dalvikvm-heap(3067): 45850-byte external allocation too large for this process.
12-23 12:23:53.134: ERROR/dalvikvm(3067): Out of memory: Heap Size=13127KB, Allocated=11913KB, Bitmap Size=11407KB
12-23 12:23:53.134: ERROR/GraphicsJNI(3067): VM won't let us allocate 45850 bytes
12-23 12:23:53.134: DEBUG/skia(3067): --- decoder->decode returned false
12-23 12:23:53.134: WARN/dalvikvm(3067): threadid=46: thread exiting with uncaught exception (group=0x400259f8)
12-23 12:23:53.134: ERROR/AndroidRuntime(3067): FATAL EXCEPTION: Thread-1016
12-23 12:23:53.134: ERROR/AndroidRuntime(3067): java.lang.OutOfMemoryError: bitmap size exceeds VM budget
12-23 12:23:53.134: ERROR/AndroidRuntime(3067):     at android.graphics.BitmapFactory.nativeDecodeStream(Native Method)
12-23 12:23:53.134: ERROR/AndroidRuntime(3067):     at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:468)
12-23 12:23:53.134: ERROR/AndroidRuntime(3067):     at android.graphics.BitmapFactory.decodeResourceStream(BitmapFactory.java:332)
12-23 12:23:53.134: ERROR/AndroidRuntime(3067):     at android.graphics.drawable.Drawable.createFromResourceStream(Drawable.java:697)
12-23 12:23:53.134: ERROR/AndroidRuntime(3067):     at android.graphics.drawable.Drawable.createFromStream(Drawable.java:657)
12-23 12:23:53.134: ERROR/AndroidRuntime(3067):     at com.nbcu.myApp.appsupport.AsyncImageLoader.loadImageFromUrl(AsyncImageLoader.java:98)
12-23 12:23:53.134: ERROR/AndroidRuntime(3067):     at com.nbcu.myApp.appsupport.AsyncImageLoader$2.run(AsyncImageLoader.java:70)
12-23 12:23:53.154: WARN/ActivityManager(96):   Force finishing activity com.nbcu.myApp.activities/com.nbcu.myApp.controllers.StoriesListController
12-23 12:23:53.224: ERROR/dalvikvm-heap(3067): 45850-byte external allocation too large for this process.
12-23 12:23:53.234: DEBUG/SurfaceFlinger(96): Layer::setBuffers(this=0x2fabc0), pid=96, w=1, h=1
12-23 12:23:53.234: ERROR/dalvikvm(3067): Out of memory: Heap Size=13127KB, Allocated=11948KB, Bitmap Size=11407KB
12-23 12:23:53.234: ERROR/GraphicsJNI(3067): VM won't let us allocate 45850 bytes
12-23 12:23:53.234: ERROR/Error(3067): Message = java.lang.OutOfMemoryError: bitmap size exceeds VM budget

下载图片的代码是:

public void run() {

        Looper.prepare();
        for (int i = 0; i < slides.size(); i++) {
            try {

                final SlideShowItem story = slides.get(i);
                if (story.getImage() == null) {
                    Drawable cachedImage = Utils.database.getRSSImage(Constants.StoriesTable, story.getItemId());

                    if (cachedImage != null) {
                        story.setImage(cachedImage);

                    } else {
                        cachedImage = asyncImageLoader.loadDrawable(story.getImagePath(), new ImageCallback() {
                            public void imageLoaded(Drawable imageDrawable, String imageUrl) {


                                story.setImage(imageDrawable);
                                Utils.database.storeRSSItemImage(Constants.StoriesTable, imageDrawable, story.getItemId());
                            }
                        });
                    }
                }

                Thread.sleep(500);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        Looper.loop();
    }

loadDrawable() 的代码是:

public Drawable loadDrawable(final String imageUrl, final ImageCallback imageCallback) {

    final Handler handler = new Handler() {

        public void handleMessage(Message message) {

            imageCallback.imageLoaded((Drawable) message.obj, imageUrl);
        }
    };
    new Thread() {

        public void run() {

                Drawable drawable = loadImageFromUrl(imageUrl);
                // System.out.println("image url: " + imageUrl);
                if (drawable != null)
                {
                    Message message = handler.obtainMessage(0, drawable);
                    handler.sendMessage(message);
                }
        }

    }.start();
    return null;
}

loadImageFromURL() 的代码是:

  public static Drawable loadImageFromUrl(String url) {

    Drawable image = null;

    try {
        InputStream in = (java.io.InputStream) new java.net.URL(url).getContent();
        if (in != null) {
            image = Drawable.createFromStream(in, "image");
        }
        in.close();

    } catch (Exception ex) {
        // ex.printStackTrace();
        Log.v("Exception ", "Asyn Image.In LoadImageFromURL Message: " + ex.toString());

    }
    return image;
}

一旦图像被下载，它们就会被缓存。我无法找到避免此异常的解决方法。可能是什么原因？我也尝试过在 Activity 被销毁时将 ImageView 设置为 null 但它对我没有任何作用？任何帮助表示赞赏。提前致谢。

最佳答案

Android 是一个移动操作系统。它的内存有限，因此您无法缓存所有 slides.size()。我假设大小 > 15。例如，我运行一个 FastCV 算法，以高清图像作为标记，250000 x 180000 像素，如果我在 PC 上运行该程序，工作正常，如果我在手机上运行则不行，因为内存不够。

我认为你可以解决这个问题，如果只缓存 10 - 15 张图像，取决于它们的大小。如果滚动，则在已使用的内存中缓存新的。

关于java - 内存不足异常，处理位图时，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/8613537/