Android BitmapFactory 无法解码输入流

Question

我正试图从Web服务器获取图像，如下所示：

@Override
    protected InputStream doInBackground(String... strings) {
        InputStream stream = null;
        try {
            URL url = new URL(strings[0]);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.connect();
            stream = connection.getInputStream();
            connection.disconnect();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } finally {
            return stream;
        }
    }
    @Override
    protected void onPostExecute(InputStream stream) {
        try {
            BufferedInputStream buf = new BufferedInputStream(stream);
            Bitmap avatar = BitmapFactory.decodeStream(buf);
            user.avatar = avatar;
            if (user.avatar != null)
                imgAvatar.setImageBitmap(user.avatar);
            buf.close();
            stream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

但是我的Bitmap avatar为空。我一直在通过调试器查看收到的InputStream，它保存了正确的url，并且它有字段httpEngine/responseBodyIn/bytesRemaining，它保存的字节数等于图像大小。图像为.png格式。

Answer 1

好的，我使用Apache HttpClient而不是HttpUrlConnection:解决了这个问题

protected InputStream doInBackground(String... strings) {
        HttpResponse response = null;
        InputStream instream = null;
        try {
            HttpClient client = new DefaultHttpClient();
            HttpGet request = new HttpGet(new URL(strings[0]).toURI());
            response = client.execute(request);
            if (response.getStatusLine().getStatusCode() != 200) {
                return null;
            }
            BufferedHttpEntity bufHttpEntity = new BufferedHttpEntity(response.getEntity());
            instream = bufHttpEntity.getContent();
            return instream;
        }
        catch (Exception ex) {
            return null;
        }
        finally {
            if (instream != null) {
                try {
                    instream.close();
                } catch (IOException e) {
                }
            }
        }
    }
    @Override
    protected void onPostExecute(InputStream stream) {
        Bitmap avatar = BitmapFactory.decodeStream(stream);
        if (avatar != null) {
            user.avatar = avatar;
            imgAvatar.setImageBitmap(avatar);
        }
    }