android - 是否可以从 AsyncTask 内部调用另一个函数？

Question

我有一个从服务器检索数据的 AsyncTask。我需要的是在对话框中显示检索到的数据。如何调用该函数以从 AsyncTask 中创建对话框？如果我做不到，那我有什么选择？是否可以知道 AsyncTask 是否已完成？

这是我的代码:

//Function calling the AsyncTask
public void getData(int pos)
{
new DBTask().execute();
//Is it possible to know here if the AsyncTask has ended or not??
}

private class DBTask extends AsyncTask<Long, Boolean, Integer>{ 
    ProgressDialog ServerPD = new ProgressDialog(MRRankingActivity.this); 

    @Override
    protected void onPreExecute() 
    {
        ServerPD = ProgressDialog.show (MRRankingActivity.this, "", "Connecting to server...", true, false);
    }//End of onPreExecute

    @Override
    protected Integer doInBackground(Long... params) 
    {
        publishProgress(isOnline());

            if(isOnline())
            {
            getDBData();
                    if(isOK)
                        {
                    //I want to show the result by calling this function..
                        showResult();
//Calling this function will trow error..So how can i show my result??
                        Log.d("LIST","DONE..Reached Final Destination");

                        }
            }   
        }

        return null;
    }

        @Override
    protected void onProgressUpdate(Boolean... isConnection) {
    // TODO Auto-generated method stub

    super.onProgressUpdate(isConnection);
    if(isOnline())
            {   
            ServerPD.setMessage("Retreving Data");
            }
    }

        @Override
    protected void onPostExecute(Integer result) {
        if (ServerPD.isShowing())
        {
            ServerPD.dismiss(); 
        }


    }//End of onPostExecute
}//End of DBTask

public void getDBData()
{

    try{
    //Code foe connecting to database and retreive data.
    //If everything is ok then isOK is set to True..
    //else its set to false       

        isOK=true;
           }
    catch(Exception e)
        {
            isOK=false;
        }//End if catch
}

public void showResult()
{
    //I want to show result here in a new Dialog ...
}

//Checking is connection available
public boolean isOnline() {
    ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo netInfo = cm.getActiveNetworkInfo();
    if (netInfo != null && netInfo.isConnectedOrConnecting()) {
        return true;
    }
    return false;
}

在这种情况下如何显示结果？有什么方法可以判断 AsyncTask 是否已经结束？

Answer 1

简化 Mathew 建议的内容..只需像这样修改您的代码首先通过初始化一个 int 变量 isSuccess 来修改 doInBackgroud，然后在 isOK if 语句中将 isSucces 的值更改为 1。现在返回 isSuccess.like this

 @Override
    protected Integer doInBackground(Long... params) 
    {
        int isSuccess=0;
        publishProgress(isOnline());

            if(isOnline())
            {

            getDBData();
                    if(isOK)
                        {
                        isSuccess=1;
                        }
            }   
        }

        return isSuccess;
    }

现在修改您的 PostExecute() 以处理在 onPostExecute 中返回的 isSuccess 值

@Override
    protected void onPostExecute(Integer result) {
        if (ServerPD.isShowing())
        {
            ServerPD.dismiss(); 
        }
        if(result==1)
            {
                showResult();
            }

    }//End of onPostExecute

希望这对您有所帮助。