如何从android中的异步任务返回值 [英] How to return value from async task in android

问题描述

我创建了一个异步任务来调用我的服务器以从数据库中获取数据.
我需要处理从 http 服务器调用返回的结果.
从我的活动中，我在很多地方调用了异步任务.所以我不能使用成员变量来访问结果.有什么办法吗?

I created an async task to call my server to get data from DB.
I need to process the result returned from http server call.
From my activity i calling the async task in many places. so i cant use member variable to access the result. is there any way to do?

public Result CallServer(String params)
{

    try
    {
    new MainAynscTask().execute(params);
    }
    catch(Exception ex)
    {
        ex.printStackTrace();
    }
    return aResultM;//Need to get back the result

}  

    private class MainAynscTask extends AsyncTask<String, Void, Result> {


    @Override
    protected Result doInBackground(String... ParamsP) {    
        //calling server codes
        return aResultL;
    }       
    @Override
       protected void onPostExecute(Result result) {
          super.onPostExecute(result);
          //how i will pass this result where i called this task?
       }

推荐答案

在调用 execute() 方法后尝试调用 AsyncTask 的 get() 方法.这对我有用

Try to call the get() method of AsyncTask after you call the execute() method. This works for me

http://developer.android.com/reference/android/os/AsyncTask.html#get()

public Result CallServer(String params)
{
   try
   {
       MainAynscTask task = new MainAynscTask();
       task.execute(params);
       Result aResultM = task.get();  //Add this
   }
   catch(Exception ex)
   {
       ex.printStackTrace();
   }
   return aResultM;//Need to get back the result

} 
...
...

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