如果你想一步调整大小你可以加载整个位图如果 android:largeHeap = true，但正如你所看到的，这是不可取的。

From docs: android:largeHeap Whether your application's processes should be created with a large Dalvik heap. This applies to all processes created for the application. It only applies to the first application loaded into a process; if you're using a shared user ID to allow multiple applications to use a process, they all must use this option consistently or they will have unpredictable results. Most apps should not need this and should instead focus on reducing their overall memory usage for improved performance. Enabling this also does not guarantee a fixed increase in available memory, because some devices are constrained by their total available memory.

这是一篇采用不同方法调整大小的文章。它将尝试根据进程中的可用内存将最大的位图加载到内存中，然后执行转换。

http://bricolsoftconsulting.com/2012/12/07/handling-large-images-on-android/

 Bitmap yourBitmap;
 Bitmap resized = Bitmap.createScaledBitmap(yourBitmap, newWidth, newHeight, true);

or:

 resized = Bitmap.createScaledBitmap(yourBitmap,(int)(yourBitmap.getWidth()*0.8), (int)(yourBitmap.getHeight()*0.8), true);

不。我希望有人能纠正我，但我接受了你作为妥协尝试的加载/调整大小的方法。

下面是浏览网页的步骤:

计算最大可能的在samplesize仍然产生比你的目标更大的图像。 使用BitmapFactory.decodeFile(file, options)加载图像，传入samplesize作为选项。 使用Bitmap.createScaledBitmap()将大小调整到所需的尺寸。

为什么不使用API呢?

int h = 48; // height in pixels
int w = 48; // width in pixels    
Bitmap scaled = Bitmap.createScaledBitmap(largeBitmap, w, h, true);

这可能对其他研究这个问题的人有用。我重写了Justin的代码，以允许该方法也接收所需的目标大小对象。这在使用Canvas时工作得非常好。所有的功劳都应该归于JUSTIN的出色的初始代码。

    private Bitmap getBitmap(int path, Canvas canvas) {

        Resources resource = null;
        try {
            final int IMAGE_MAX_SIZE = 1200000; // 1.2MP
            resource = getResources();

            // Decode image size
            BitmapFactory.Options options = new BitmapFactory.Options();
            options.inJustDecodeBounds = true;
            BitmapFactory.decodeResource(resource, path, options);

            int scale = 1;
            while ((options.outWidth * options.outHeight) * (1 / Math.pow(scale, 2)) > 
                  IMAGE_MAX_SIZE) {
               scale++;
            }
            Log.d("TAG", "scale = " + scale + ", orig-width: " + options.outWidth + ", orig-height: " + options.outHeight);

            Bitmap pic = null;
            if (scale > 1) {
                scale--;
                // scale to max possible inSampleSize that still yields an image
                // larger than target
                options = new BitmapFactory.Options();
                options.inSampleSize = scale;
                pic = BitmapFactory.decodeResource(resource, path, options);

                // resize to desired dimensions
                int height = canvas.getHeight();
                int width = canvas.getWidth();
                Log.d("TAG", "1th scale operation dimenions - width: " + width + ", height: " + height);

                double y = Math.sqrt(IMAGE_MAX_SIZE
                        / (((double) width) / height));
                double x = (y / height) * width;

                Bitmap scaledBitmap = Bitmap.createScaledBitmap(pic, (int) x, (int) y, true);
                pic.recycle();
                pic = scaledBitmap;

                System.gc();
            } else {
                pic = BitmapFactory.decodeResource(resource, path);
            }

            Log.d("TAG", "bitmap size - width: " +pic.getWidth() + ", height: " + pic.getHeight());
            return pic;
        } catch (Exception e) {
            Log.e("TAG", e.getMessage(),e);
            return null;
        }
    }

Justin的代码非常有效地减少了使用大型位图的开销。