Android，内存不足转换为黑白

Question

当用户触摸某些资源时，我会将它们转换为黑白。我的 Util java 文件中有这个功能:

public static Bitmap convertColorIntoBlackAndWhiteImage(Bitmap orginalBitmap) {
    ColorMatrix colorMatrix = new ColorMatrix();
    colorMatrix.setSaturation(0);

    ColorMatrixColorFilter colorMatrixFilter = new ColorMatrixColorFilter(colorMatrix);
    Bitmap blackAndWhiteBitmap = orginalBitmap.copy(Bitmap.Config.ARGB_8888, true);

    Paint paint = new Paint();
    paint.setColorFilter(colorMatrixFilter);

    Canvas canvas = new Canvas(blackAndWhiteBitmap);
    canvas.drawBitmap(blackAndWhiteBitmap, 0, 0, paint);

    return blackAndWhiteBitmap;
}

但有时，在某些设备上我会收到此错误:

java.lang.OutOfMemoryError
at android.graphics.Bitmap.nativeCopy(Native Method)
at android.graphics.Bitmap.copy(Bitmap.java:479)
at com.mygame.util.Util.convertColorIntoBlackAndWhiteImage(Util.java:145)

该函数的第 145 行是

Bitmap blackAndWhiteBitmap = orginalBitmap.copy(Bitmap.Config.ARGB_8888, true);

准确地说，我从其他 stackoverflow 答案中获取了该函数。

发生了什么事？

谢谢

Answer 1

这可能对你有帮助...

public static Bitmap convertColorIntoBlackAndWhiteImage(Bitmap orginalBitmap) {
    ColorMatrix colorMatrix = new ColorMatrix();
    colorMatrix.setSaturation(0);

    ColorMatrixColorFilter colorMatrixFilter = new ColorMatrixColorFilter(
            colorMatrix);
    Bitmap blackAndWhiteBitmap = orginalBitmap.copy(
            Bitmap.Config.ARGB_8888, true);
    // Recycle the Bitmap and free the memory once you copied into new
    // Bitmap
    orginalBitmap.recycle();
    orginalBitmap = null;
    // still problem exists call
    // System.gc();
    // System.gc();

    Paint paint = new Paint();
    paint.setColorFilter(colorMatrixFilter);

    Canvas canvas = new Canvas(blackAndWhiteBitmap);
    canvas.drawBitmap(blackAndWhiteBitmap, 0, 0, paint);

    return blackAndWhiteBitmap;
}

您似乎正在尝试将图像转换为灰色。试试这个……

    public static Bitmap toGrayBitmap(Bitmap bitmap) {
        if (bitmap == null || bitmap.isRecycled()) {
            return null;
        }
        final int width = bitmap.getWidth();
        final int height = bitmap.getHeight();

        Bitmap canvasBitmap = Bitmap.createBitmap(width, height,
                Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(canvasBitmap);
        canvas.drawARGB(0, 0, 0, 0);

        Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
        paint.setColor(Color.WHITE);
        ColorMatrix colorMatrix = new ColorMatrix();
        colorMatrix.setSaturation(0);
        ColorMatrixColorFilter filter = new ColorMatrixColorFilter(
                colorMatrix);
        paint.setColorFilter(filter);

        canvas.drawBitmap(bitmap, 0, 0, paint);
        bitmap.recycle(); // do it if still problem exists

        return canvasBitmap;
    }