BitmapFactory.Options

BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
bmpFactoryOptions.inSampleSize = 8;
Bitmap bmp = BitmapFactory.decodeFile(imageFilePath, bmpFactoryOptions);
imv.setImageBitmap(bmp);

上面的代码使图片变成原来的1/8.

    //imv = (ImageView) findViewById(R.id.ReturnedImageView);
            Display currentDisplay = getWindowManager().getDefaultDisplay();
            int dw = currentDisplay.getWidth();
            int dh = currentDisplay.getHeight();
           try
           {
            BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
            bmpFactoryOptions.inJustDecodeBounds = true;
            Bitmap bmp = BitmapFactory.decodeStream(getContentResolver().
                    openInputStream(imageFileUri), null,  bmpFactoryOptions);

            int heightRatio = (int)Math.ceil(bmpFactoryOptions.outHeight/(float)dh);
            int widthRatio = (int)Math.ceil(bmpFactoryOptions.outWidth/(float)dw);

            Log.v("HEIGHRATIO", ""+heightRatio);
            Log.v("WIDTHRATIO", ""+widthRatio);

            if (heightRatio > 1 && widthRatio > 1)
            {
                bmpFactoryOptions.inSampleSize =  heightRatio > widthRatio ? heightRatio:widthRatio;
            }
            bmpFactoryOptions.inJustDecodeBounds = false;
            bmp = BitmapFactory.decodeStream(getContentResolver().
                    openInputStream(imageFileUri), null,  bmpFactoryOptions);
            returnedImageView.setImageBitmap(bmp);
           }
           catch (FileNotFoundException e)
           {
               Log.v("ERROR", e.toString());

           }

上面的代码让图片根据窗口大小改变

bmpFactoryOptions.inJustDecodeBounds = true;

这一行让代码只解码图片的Bounds