错误：bitmap size exceeds VM budget

?

private Bitmap decodeFile(File f){    Bitmap b = null;    try {        //Decode image size        BitmapFactory.Options o = new BitmapFactory.Options();        o.inJustDecodeBounds = true;        BitmapFactory.decodeStream(new FileInputStream(f), null, o);        int scale = 1;        if (o.outHeight > IMAGE_MAX_SIZE || o.outWidth > IMAGE_MAX_SIZE) {            scale = Math.pow(2, (int) Math.round(Math.log(IMAGE_MAX_SIZE / (double) Math.max(o.outHeight, o.outWidth)) / Math.log(0.5)));        }        //Decode with inSampleSize        BitmapFactory.Options o2 = new BitmapFactory.Options();        o2.inSampleSize = scale;        b = BitmapFactory.decodeStream(new FileInputStream(f), null, o2);    } catch (FileNotFoundException e) {    }    return b;}

?

转自http://www.cnblogs.com/RayLee/archive/2010/11/09/1872856.html

?

BitmapFactory.decodeFile(imageFile);

用BitmapFactory解码一张图片时，有时会遇到该错误。这往往是由于图片过大造成的。要想正常使用，则需要分配更少的内存空间来存储。

BitmapFactory.Options.inSampleSize

设置恰当的inSampleSize可以使BitmapFactory分配更少的空间以消除该错误。inSampleSize的具体含义请参考SDK文档。例如：

BitmapFactory.Options opts = new BitmapFactory.Options();opts.inSampleSize = 4;Bitmap bitmap = BitmapFactory.decodeFile(imageFile, opts);

?

?

设置恰当的inSampleSize是解决该问题的关键之一。BitmapFactory.Options提供了另一个成员inJustDecodeBounds。

BitmapFactory.Options opts = new BitmapFactory.Options();opts.inJustDecodeBounds = true;Bitmap bitmap = BitmapFactory.decodeFile(imageFile, opts);

?

设置inJustDecodeBounds为true后，decodeFile并不分配空间，但可计算出原始图片的长度和宽度，即opts.width和opts.height。有了这两个参数，再通过一定的算法，即可得到一个恰当的inSampleSize。

查看Android源码，Android提供了一种动态计算的方法。

public static int computeSampleSize(BitmapFactory.Options options,int minSideLength, int maxNumOfPixels) {int initialSize = computeInitialSampleSize(options, minSideLength,maxNumOfPixels);int roundedSize;if (initialSize <= 8) {roundedSize = 1;while (roundedSize < initialSize) {roundedSize <<= 1;}} else {roundedSize = (initialSize + 7) / 8 * 8;}return roundedSize;}private static int computeInitialSampleSize(BitmapFactory.Options options,int minSideLength, int maxNumOfPixels) {double w = options.outWidth;double h = options.outHeight;int lowerBound = (maxNumOfPixels == -1) ? 1 :(int) Math.ceil(Math.sqrt(w * h / maxNumOfPixels));int upperBound = (minSideLength == -1) ? 128 :(int) Math.min(Math.floor(w / minSideLength),Math.floor(h / minSideLength));if (upperBound < lowerBound) {// return the larger one when there is no overlapping zone.return lowerBound;}if ((maxNumOfPixels == -1) &&(minSideLength == -1)) {return 1;} else if (minSideLength == -1) {return lowerBound;} else {return upperBound;}}使用该算法，就可动态计算出图片的inSampleSize。BitmapFactory.Options opts = new BitmapFactory.Options();opts.inJustDecodeBounds = true;BitmapFactory.decodeFile(imageFile, opts);opts.inSampleSize = computeSampleSize(opts, -1, 128*128);opts.inJustDecodeBounds = false;try {Bitmap bmp = BitmapFactory.decodeFile(imageFile, opts);imageView.setImageBitmap(bmp);} catch (OutOfMemoryError err) {}另外，可以通过Bitmap.recycle()方法来释放位图所占的空间，当然前提是位图没有被使用。

?