java.lang.OutOfMemoryError: bitmap size exceeds VM budget解决方法
1BitmapFactory.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：
view sourceprint?
1BitmapFactory.Options opts = new BitmapFactory.Options();2opts.inSampleSize = 4;3Bitmap bitmap = BitmapFactory.decodeFile(imageFile, opts);如何设置恰当的inSampleSize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。
view sourceprint?1BitmapFactory.Options opts = new BitmapFactory.Options();2opts.inJustDecodeBounds = true;3Bitmap 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。
view sourceprint?01public static int computeSampleSize(BitmapFactory.Options options,02????????int minSideLength, int maxNumOfPixels) {03????int initialSize = computeInitialSampleSize(options, minSideLength,04????????????maxNumOfPixels);05?06????int roundedSize;07????if (initialSize <= 8) {08????????roundedSize = 1;09????????while (roundedSize < initialSize) {10????????????roundedSize <<= 1;11????????}12????} else {13????????roundedSize = (initialSize + 7) / 8 * 8;14????}15?16????return roundedSize;17}18?19private static int computeInitialSampleSize(BitmapFactory.Options options,20????????int minSideLength, int maxNumOfPixels) {21????double w = options.outWidth;22????double h = options.outHeight;23?24????int lowerBound = (maxNumOfPixels == -1) ? 1 :25????????????(int) Math.ceil(Math.sqrt(w * h / maxNumOfPixels));26????int upperBound = (minSideLength == -1) ? 128 :27????????????(int) Math.min(Math.floor(w / minSideLength),28????????????Math.floor(h / minSideLength));29?30????if (upperBound < lowerBound) {31????????// return the larger one when there is no overlapping zone.32????????return lowerBound;33????}34?35????if ((maxNumOfPixels == -1) &&36????????????(minSideLength == -1)) {37????????return 1;38????} else if (minSideLength == -1) {39????????return lowerBound;40????} else {41????????return upperBound;42????}43}?? 使用该算法，就可动态计算出图片的inSampleSize。
01BitmapFactory.Options opts = new BitmapFactory.Options();02opts.inJustDecodeBounds = true;03BitmapFactory.decodeFile(imageFile, opts);04?????????????05opts.inSampleSize = computeSampleSize(opts, -1, 128*128);?????? 06opts.inJustDecodeBounds = false;07try {08????Bitmap bmp = BitmapFactory.decodeFile(imageFile, opts);09????imageView.setImageBitmap(bmp);10????} catch (OutOfMemoryError err) {11????}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。