异步获取网络图片Bitmap

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从网路获取图片，使用AsyncTask异步通信。

异步代码如下：

    public void addTask(String url) {        new AsyncTask<String, Void, Bitmap>() {            @Override            protected Bitmap doInBackground(String... params) {                // 后台通信                return decodeBitmap(params[0]);//                return byteBitmap(params[0]);            }            @Override            protected void onPostExecute(Bitmap bitmap) {                // 主线程处理view                if (bitmap != null) {                    mTestImage.setImageBitmap(bitmap);                }            }        }.execute(url);    }

后台处理方法

方法一：使用 BitmapdecodeStream(InputStream is)

    private Bitmap decodeBitmap(String httpUrl) {        URL url = null;        Bitmap bm = null;        try {            url = new URL(httpUrl);        } catch (MalformedURLException e) {            e.printStackTrace();        }        try {            InputStream in = url.openStream();            bm = BitmapFactory.decodeStream(in);        } catch (IOException e) {            e.printStackTrace();        }        return bm;    }

方法二：使用BitmapFactory.decodeByteArray(data,0,data.length)

    private Bitmap byteBitmap(String httpUrl) {        Bitmap bitmap = null;        try {            HttpURLConnection connection = (HttpURLConnection)(new URL(httpUrl)).openConnection();            connection.setDoInput(true);            connection.connect();            InputStream is = connection.getInputStream();            try {                byte[] data = readStream(is);                if(data != null){                    bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);                }            } catch (Exception e) {                e.printStackTrace();            } finally {                is.close();            }        } catch (IOException e) {            e.printStackTrace();        }        return bitmap;    }    public static byte[] readStream(InputStream inStream) throws Exception{        ByteArrayOutputStream outStream = new ByteArrayOutputStream();        byte[] buffer = new byte[1024];        int len = 0;        while((len=inStream.read(buffer)) != -1){            outStream.write(buffer, 0, len);        }        outStream.close();        inStream.close();        return outStream.toByteArray();    }

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