Question

我最近使用Asynctask创建了一个ImageDownloader方法，现在我需要完全相同的方法来下载当前项目中的音频。你能帮我编辑这个方法吗？

（如果我在这里有一些错误，请更正我，因为我是android的新手）

这是我的ImageDownloader AsynkTask：

    public class ImageDownloader extends AsyncTask<String, String, String> {

     private PowerManager.WakeLock mWakeLock;

    @Override
    protected void onPreExecute() {
        super.onPreExecute(); 

        PowerManager pm = (PowerManager) getActivity().getSystemService(Context.POWER_SERVICE);
        mWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
             getClass().getName());
        mWakeLock.acquire();
        mProgressDialog = new ProgressDialog(getActivity());
        mProgressDialog.setTitle("Downloading...");
        mProgressDialog.setMessage("Please wait while your file is downloading...");
        mProgressDialog.setIndeterminate(false);
        mProgressDialog.setCancelable(true);
        mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        mProgressDialog.setMax(100);
        mProgressDialog.setProgress(100);



        mProgressDialog.show();
    }

    @Override
    protected String doInBackground(String... image_urls) {
         int count = 0;
        try {  

             URL url = new URL(image_urls[0]);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection(); 
            conn.setDoInput(true);   
            conn.connect();     
            InputStream is = conn.getInputStream();
            bmImg = BitmapFactory.decodeStream(is);

            while(count != 100){
                publishProgress(""+count);
                count +=5;
            }
        }
        catch (IOException e)
        {       
            e.printStackTrace();  
        }

        return null;   
    }

    @Override
    protected void onProgressUpdate(String... progress) {
        Log.v("count",progress[0]);
        mProgressDialog.setProgress(Integer.parseInt(progress[0]));
   }     

@Override       
protected void onPostExecute(String args) {

             mWakeLock.release();      
             File showPathInToast;
             File filename;
             try {
                 String path = Environment.getExternalStorageDirectory().toString();
                 Log.i("in save()", "after mkdir");
                 new File(path + "/Dastak/News").mkdirs();

                 String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
                 String imageFileName = timeStamp;

                 filename = new File(path + "/Dastak/News/"+ imageFileName +".jpg");
                 showPathInToast = new File(path + "/Dastak/News/");

                 Log.i("in save()", "after file");
                 FileOutputStream out = new FileOutputStream(filename);
                 Log.i("in save()", "after outputstream");
                 bmImg.compress(Bitmap.CompressFormat.JPEG, 90, out);
                 out.flush();
                 out.close();
                 Log.i("in save()", "after outputstream closed");
                 // MediaStore.Images.Media.insertImage(getActivity().getContentResolver(),
                 //filename.getAbsolutePath(), filename.getName(),filename.getName());

                 Toast.makeText(getActivity().getApplicationContext(),
                         "File has been saved to " + showPathInToast , Toast.LENGTH_LONG).show();
             } catch (Exception e) {
                 e.printStackTrace();
             }

             mProgressDialog.dismiss();
        }
      }

Answer 1

这是一个简单的AsyncTask。在构造函数中指定目标File，在调用execute时指定url。它只是读取InputStream，直到它什么都不返回，并使用FileOutputStream直接写入目标文件。

private class FileDownloadTask extends AsyncTask<String, Void, Void> {

    File destination;

    public FileDownloadTask(File destination) {
        this.destination = destination;
    }

    @Override
    protected Void doInBackground(String... urls) {
        HttpURLConnection conn = null;
        try {
            URL url = new URL(urls[0]);
            conn = (HttpURLConnection) url.openConnection();
            conn.setDoInput(true);
            conn.connect();

            if(!destination.exists()) {
                if(!destination.mkdirs()) {
                    return null;
                }
            }

            InputStream is = conn.getInputStream();
            FileOutputStream fos = new FileOutputStream(destination);

            byte[] bytes = new byte[1024];

            while ((is.read(bytes) >= 0)) {
                fos.write(bytes);
            }

            fos.flush();
            fos.close();
            is.close();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if(conn != null) {
                conn.disconnect();
            }
        }
        return null;
    }
}

显然，您可以再次添加ProgressDialog逻辑。

使用AsyncTask创建Audio Downloader方法

1 个答案: