Question

我的代码是：

public Bitmap loadPhoto(Uri uri) {
    Bitmap scaled = null;
    try {
    scalled = Bitmap.createBitmap(
      MediaStore.Images.Media.getBitmap(getContentResolver(), uri),
      0,0,90, 90);

    if (scaled == null) { return null; }
    } catch(Exception e) { }
    return scaled;
}

之后。我在ImageView中显示缩放。每张图片都来自设备相机。

每次从相机显示三张照片后，我都会收到错误：内存不足。怎么解决这个问题？

Answer 1

尝试使用BitmapFactory解决问题http://developer.android.com/reference/android/graphics/BitmapFactory.html

Answer 2

对于那些正在寻找代码示例的人：

private 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) {

        final int halfHeight = height / 2;
        final int halfWidth = width / 2;

        // Calculate the largest inSampleSize value that is a power of 2 and keeps both
        // height and width larger than the requested height and width.
        while ((halfHeight / inSampleSize) >= reqHeight
                && (halfWidth / inSampleSize) >= reqWidth) {
            inSampleSize *= 2;
        }
    }

    return inSampleSize;
}

public static Bitmap decodeSampledBitmapFromUri(Context context, Uri imageUri, int reqWidth, int reqHeight) throws FileNotFoundException {

    // Get input stream of the image
    final BitmapFactory.Options options = new BitmapFactory.Options();
    InputStream iStream = context.getContentResolver().openInputStream(imageUri);

    // First decode with inJustDecodeBounds=true to check dimensions
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeStream(iStream, null, options);

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

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeStream(iStream, null, options);
}

Answer 3

Praveen Katha的答案将始终返回null。这是更新的答案。

这是诀窍，每次使用后都要关闭输入流。输入流意味着要使用一次。有关更多信息，请遵循此answer

private 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) {

            final int halfHeight = height / 2;
            final int halfWidth = width / 2;

            // Calculate the largest inSampleSize value that is a power of 2 and keeps both
            // height and width larger than the requested height and width.
            while ((halfHeight / inSampleSize) >= reqHeight
                    && (halfWidth / inSampleSize) >= reqWidth) {
                inSampleSize *= 2;
            }
        }

        return inSampleSize;
    }

    public static Bitmap decodeSampledBitmapFromUri(Context context, Uri imageUri, int reqWidth, int reqHeight) throws FileNotFoundException {
        Bitmap bitmap = null;
        try {
            // Get input stream of the image
            final BitmapFactory.Options options = new BitmapFactory.Options();
            InputStream iStream = context.getContentResolver().openInputStream(imageUri);

            // First decode with inJustDecodeBounds=true to check dimensions
            options.inJustDecodeBounds = true;
            BitmapFactory.decodeStream(iStream, null, options);
            if (iStream != null) {
                iStream.close();
            }
            iStream = context.getContentResolver().openInputStream(imageUri);

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

            // Decode bitmap with inSampleSize set
            options.inJustDecodeBounds = false;
            bitmap = BitmapFactory.decodeStream(iStream, null, options);
            if (iStream != null) {
                iStream.close();
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return bitmap;
    }

Answer 4

MediaStore.getBitmap方法是一种便捷方法，在获取位图时不指定样本大小。如果您正在使用getBitmap（ContentResolver，Uri），并且想要使用样本大小，只需使用ContentResolver获取输入流，并像平常一样解码位图（首先计算样本大小，然后使用适当的方法加载它）样本量）。

MediaStore.Images.Media.getBitmap和内存不足错误

4 个答案: