0

我有一个基于 Web 的应用程序，它必须在检索一个文本后检索外部数据库中的文本和服务器中的图像，使用以下代码检索文本：

class BackgroundTaskOne extends AsyncTask<Void, Void, String>
{

    String json_url;
    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub          
        json_url="http://..some url../somefile.php";

    }

    @Override
    protected String doInBackground(Void... voids) {
        // TODO Auto-generated method stub              

        String error="";
        try {
            URL url=new URL(json_url);

            HttpURLConnection httpUrlConnection=(HttpURLConnection) url.openConnection();

            InputStream inputStream=httpUrlConnection.getInputStream();
            BufferedReader bufferReader=new BufferedReader(new InputStreamReader(inputStream));

            StringBuilder stringBuilder=new StringBuilder();

            while((JSON_STRINO=bufferReader.readLine())!=null){

                stringBuilder.append(JSON_STRINO+"\n");
                //add new textView  
            }

            bufferReader.close();
            inputStream.close();
            httpUrlConnection.disconnect();
            json_string=stringBuilder.toString().trim();
            return stringBuilder.toString().trim();
           // return "one row of data inserted..";
        } catch (MalformedURLException e) {
            error=e.getMessage()+" first";
        } catch (IOException e) {
            // TODO Auto-generated catch block
            error=e.getMessage()+" sec";
        }
        return error;
    }

    @Override
    protected void onProgressUpdate(Void... values) {
        // TODO Auto-generated method stub
        super.onProgressUpdate(values);
    }


    @Override
    protected void onPostExecute(String result) {
        // TODO Auto-generated method stub
        json_string=result;
        l=parse();


           int i=0;

           for(final String a[]:l){

               TextView t=new TextView(MainActivity.this);

               final String path=a[2]+".jpg";
                t.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
               t.setText(a[0]+" : "+a[1]+" i="+i);             
                t.setId(i);
                Reklam.addView(t);

                new LoadImage().execute(path);

            i++;
    }}}

我想在按顺序加载第一个文本和第二个文本之后的第二个图像时加载图像，但它会加载所有文本然后加载所有图像，这些加载图像的代码如下：

 private class LoadImage extends AsyncTask<String, String, Bitmap> {
    Bitmap bitmap;
    ProgressDialog pDialog;
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(MainActivity.this);
        pDialog.setMessage("Loading Image ....");
        pDialog.show();

    }
     protected Bitmap doInBackground(String... args) {
         try {
               bitmap = BitmapFactory.decodeStream((InputStream)new URL(args[0]).getContent());

        } catch (Exception e) {
              e.printStackTrace();
        }
        return bitmap;
     }

     protected void onPostExecute(Bitmap image) {

         if(image != null){
         ImageView img=new ImageView(MainActivity.this);
         img.setImageBitmap(image);
         img.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
            Reklam.addView(img);
         pDialog.dismiss();

         }else{

         pDialog.dismiss();
         Toast.makeText(MainActivity.this, "Image Does Not exist or Network Error", Toast.LENGTH_SHORT).show();

         }
     }
 }
4

1 回答 1

0

如果要并行运行多个线程：

 if( Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ) {
        new MyAsyncTask().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
    } else {
        new MyAsyncTask().execute();
    }
于 2016-04-26T19:15:11.390 回答