BitmapFactory.decodeStream（stream，null，options）时重用InputStream

Question

InputStream stream = new URL(key).openStream();

BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;

BitmapFactory.decodeStream(stream, null, options);

options.inSampleSize = calculateInSampleSize(options, reqWidth,
            reqHeight);
options.inJustDecodeBounds = false;

/* i need reuse stream here, for decode stream again. */

Bitmap bmp = BitmapFactory.decodeStream(stream, null, options);

stream.close();

return bmp;

Answer 1

您始终只需从网址

重新打开流即可

InputStream stream = new URL(key).openStream();

或者我们像Guava这样的库（ByteStreams）来完全阅读InputStream并将结果字节分配到ByteArrayInputStream

InputStream stream = new URL(key).openStream();
ByteArrayOutputStream out = new ByteArrayOutputStream();
ByteStreams.copy(stream, out);
ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());

// use it once
in.reset();
// use it again

如果您的代码在流上调用mark()，请小心。如果发生这种情况，只需使用ByteArrayInputStream ByteArrayOutputStream中的字节创建一个新的out.toByteArray()。