Android位图OutOfMemoryError [重复]

Question

我的 VSD220 出现 OutOfMemoryError（它是基于 Android 的 22 英寸一体机）

for (ImageView img : listImages) {
            System.gc();

            Bitmap myBitmap = BitmapFactory.decodeFile(path);
            img.setImageBitmap(myBitmap);
            img.setOnClickListener(this);
        }

我真的不知道该怎么办，因为这张图片低于最大分辨率。图像大小约为 (1000x1000)，显示为 1920x1080。

有什么帮助吗？ （那个 foreach 循环大约有 20 个元素，它在 6 或 7 个循环后被破坏..）

非常感谢。

伊泽奎尔。

Answer 1

您应该查看Managing Bitmap Memory 的培训文档。根据您的操作系统版本，您可以使用不同的技术来管理更多位图，但无论如何您可能都必须更改代码。

特别是，您可能不得不使用“Load a Scaled Down Version into Memory”中代码的修改版本，但我至少发现这部分特别有用：

public static int calculateInSampleSize(
            BitmapFactory.Options options, int reqWidth, int reqHeight) {
    // Raw height and width of image
    final int height = options.outHeight;
    final int width = options.outWidth;
    int inSampleSize = 1;

    if (height > reqHeight || width > reqWidth) {

        // Calculate ratios of height and width to requested height and width
        final int heightRatio = Math.round((float) height / (float) reqHeight);
        final int widthRatio = Math.round((float) width / (float) reqWidth);

        // Choose the smallest ratio as inSampleSize value, this will guarantee
        // a final image with both dimensions larger than or equal to the
        // requested height and width.
        inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
    }

    return inSampleSize;
}



public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
        int reqWidth, int reqHeight) {

    // First decode with inJustDecodeBounds=true to check dimensions
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeResource(res, resId, options);

    // Calculate inSampleSize
    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeResource(res, resId, options);
}

这种方法可以轻松加载任意大尺寸的位图 进入一个显示 100x100 像素缩略图的 ImageView，如图所示 以下示例代码：

mImageView.setImageBitmap(
decodeSampledBitmapFromResource(getResources(), R.id.myimage, 100, 100));

Answer 2

您确定要加载同一个位图 20 次吗？您不想加载一次并将其设置在循环中吗？

不过，无论屏幕分辨率如何，都不能保证加载 1000x1000 像素的图像。请记住，1000x1000 像素的图像占用 1000x1000x4 字节 =~4MB（如果将其加载为 ARGB_8888）。如果您的堆内存碎片/太小，您可能没有足够的空间来加载位图。您可能想查看BitmapFactory.Options 类并尝试使用inPreferredConfig 和inSampleSize

我建议您要么使用 DigCamara 的建议并确定尺寸并加载接近该尺寸的下采样图像（我说几乎是因为您不会使用该技术获得确切的尺寸），或者您尝试加载完整大小的图像，然后递归地增加样本大小（为获得最佳结果，增加两倍），直到达到最大样本大小或加载图像：

/**
 * Load a bitmap from a stream using a specific pixel configuration. If the image is too
 * large (ie causes an OutOfMemoryError situation) the method will iteratively try to
 * increase sample size up to a defined maximum sample size. The sample size will be doubled
 * each try since this it is recommended that the sample size should be a factor of two
 */
public Bitmap getAsBitmap(InputStream in, BitmapFactory.Config config, int maxDownsampling) {
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inSampleSize = 1;   
    options.inPreferredConfig = config;
    Bitmap bitmap = null;
    // repeatedly try to the load the bitmap until successful or until max downsampling has been reached
    while(bitmap == null && options.inSampleSize <= maxDownsampling) {
        try {
            bitmap = BitmapFactory.decodeStream(in, null, options);
            if(bitmap == null) {
                // not sure if there's a point in continuing, might be better to exit early
                options.inSampleSize *= 2;
            }
        }
        catch(Exception e) {
            // exit early if we catch an exception, for instance an IOException
            break;
        }
        catch(OutOfMemoryError error) {
            // double the sample size, thus reducing the memory needed by 50%
            options.inSampleSize *= 2;
        }
    }
    return bitmap;
}