Question

当我的应用程序第一次启动时，它应该显示用户协议，这是一个59kb的txt文件。由于它需要一些时间来读取文件并将其附加到文本视图，我决定在Async任务中执行该操作并显示进度条，但是进度条会冻结，直到文件被附加到文本视图，当发生这种情况时，应用程序需要一些时间来响应，有时会导致ANR。这是我的异步任务代码：

  public class DownloadFilesTask extends AsyncTask<String, Integer, String> {

    AlertDialog alertDialog = null;
    Button getstarted, cancel;  
        TextView text2;  
        AlertDialog.Builder builder;
        LayoutInflater inflater = (LayoutInflater) Profile.this.getSystemService(LAYOUT_INFLATER_SERVICE);
        View layout = inflater.inflate(R.layout.agreement, (ViewGroup) findViewById(R.id.layout_root));

protected void onPreExecute(){
     progressDialog = ProgressDialog.show(Profile.this, "", "Loading.....", true);
        getstarted=(Button) layout.findViewById(R.id.get_started);
        cancel=(Button) layout.findViewById(R.id.cancel);

        cancel.setVisibility(View.GONE);
        text2 = (TextView) layout.findViewById(R.id.ag);

        builder = new Builder(Profile.this);
        builder.setView(layout);
        alertDialog = builder.create();
        alertDialog.setCancelable(false);
         alertDialog.setTitle(getString(R.string.terms));   
    }

@Override
protected String doInBackground(String... arg0) {
     StringBuilder sb = new StringBuilder();
try {
        AssetManager am = getAssets();
        InputStream in = am.open("EULA.txt");
         BufferedReader reader = new BufferedReader(new InputStreamReader(in));

            String line = null;

            while ((line = reader.readLine()) != null) {
                sb.append(line);
            }

            in.close();


    } catch(Exception e){

           System.out.println("FILE NOT FOUND : "+ e.getMessage());
    }

       return sb.toString();
        }
 // This is called when doInBackground() is finished
  protected void onPostExecute(String result) {
      progressDialog.dismiss();
      alertDialog.show();
        text2.setText(Html.fromHtml(result));  

       }

       // This is called each time you call publishProgress()
}

如您所见，我将文件附加到postExecute方法的文本视图中。我应该改变我正在阅读文件的方式吗？或者是别的什么。提前致谢

Answer 1

首先，您可以使用onProgressUpdate更新进度条。

为了避免你的ANR我怀疑Html.fromHtml是一个阻止你的UI线程的昂贵的调用。您可以在doInBackground方法中返回Html值，并避免UI阻塞。

example of use onProgressUpdate to update the progress bar

AsyncTask期间的UI冻结

1 个答案: