Solution to BitmapFactory decodeStream null

 最近遇到從網絡上下載圖片，解碼一直是null的問題:

.....

Bitmap bitmap=BitmapFactory.decodeStream(inputStream);

....

開始時以爲TimeOut太短，或者buffersize太小的問題，修改後仍然沒有解決問題，記得同樣的方法以前下載圖片挺正常的，Google之，找到了問題的答案，起碼解決了我的問題。

網上類似的問題：

http://stackoverflow.com/questions/3802820/bitmapfactory-decodestream-always-returns-null-and-skia-decoder-shows-decode-ret

原來是系統bug，2.1版本中仍存在這個問題：

http://code.google.com/p/android/issues/detail?id=6066

The problem was indeed in the calls to the InputStream skip() method.

解決方法：

static class FlushedInputStream extends FilterInputStream {
    public FlushedInputStream(InputStream inputStream) {
        super(inputStream);
    }

    @Override
    public long skip(long n) throws IOException {
        long totalBytesSkipped = 0L;
        while (totalBytesSkipped < n) {
            long bytesSkipped = in.skip(n - totalBytesSkipped);
            if (bytesSkipped == 0L) {
                int bytes = read();
                if (bytes < 0) {
                    break; // we reached EOF
                } else {
                    bytesSkipped = 1; // we read one byte
                }
            }
            totalBytesSkipped += bytesSkipped;
        }
        return totalBytesSkipped;
    }
}

或者另外建個類。

以前的代碼改爲：

Bitmap bitmap = BitmapFactory.decodeStream(new FlushedInputStream(inputStream));

遇到同樣問題的童鞋可以參考。