如何在 android 中对位图进行采样以进行内存管理？

Question

我做了一个图像编辑演示，当我将图像传递给另一个活动（增加堆大小）时遇到问题，我的应用程序崩溃了，请告诉我如何直接采样和调整我的位图大小（不是来自资源) 解决内存问题，我的代码如下： 代码

if (Global.photo_editor_bitmap != null) {
                ByteArrayOutputStream stream = new ByteArrayOutputStream();
                Global.photo_editor_bitmap.compress(Bitmap.CompressFormat.PNG,
                        100, stream);
                byte[] byteArray = stream.toByteArray();

                i = new Intent(PhotoEditor.this, Enhance.class);
                i.putExtra("bitmap_image", byteArray);
                i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
                i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(i);
            } else {

                Toast.makeText(getApplicationContext(), "No Image", 1).show();
            }

    static int calculateInSampleSize(BitmapFactory.Options options,
            int reqWidth, int reqHeight) {
        int inSampleSize = 1; // Default subsampling size
        // See if image raw height and width is bigger than that of required
        // view
        if (options.outHeight > reqHeight || options.outWidth > reqWidth) {
            // bigger
            final int halfHeight = options.outHeight / 2;
            final int halfWidth = options.outWidth / 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;
    }

    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);
    }

我得到了decodebitmapFromresources的解决方案，但是我的位图是可用的，所以如何使用这个直接。

Answer 1

我有同样的问题，应用程序崩溃并在日志中显示堆大小、分配大小和位图大小的消息，我所做的是检查设备宽度和高度，并在此基础上缩放位图或计算样本尺寸。

int screenHeight = getResources().getDisplayMetrics().heightPixels;
int screenWidth = getResources().getDisplayMetrics().widthPixels; 

获取宽度和高度然后放到reqWidth和reqHeight中