在AsyncTask的类getApplicationContext？ [英] getApplicationContext in AsyncTask class?

问题描述

我有一对夫妇的私人AsyncTask的方法，我想闯入了公众的外部类。在我的应用程序，我有一个公共类扩展应用程序，它拥有一些共同套路我想从我的应用程序的不同部分来访问。当我不过打出来的AsyncTask的课，我不再能够调用getApplicationContext（）来获取一个引用我的应用程序库（类没有现在继承自Activity东西）。 getBaseContext（）会出现问题也是如此。我应该通过上下文到AsyncTask的，当它被实例化，并建立从那里？不知道这是否是安全与否。

 进口的java.util.ArrayList;
进口android.os.AsyncTask;

公共类dlTask​​扩展的AsyncTask
{
    长totalbytes = 0;
    长totalread = 0;
    ArrayList的＆LT;字符串＆GT;数据;

    @覆盖
    在preExecute保护无效（）
    {
        AppLib LIB =（AppLib）getApplicationContext（）;

        lib.saveStatusText（联系+ lib.getServerAddress（）+：+ lib.getServerPort（）+...）;
       super.on preExecute（）;
    }

      @覆盖
      保护对象doInBackground（对象... PARAMS）
      {
        数据= lib.sendCommand（CMD_LIST）;
         返回true;
      }

      @覆盖
      保护无效onPostExecute（对象结果）
      {

         如果（数据！= NULL）
         {
                    lib.saveStatusText（data.size（）+文件中找到）;
         }
         其他
         {
            Log.d（TAG，数据为空）;
            Toast.makeText（getBaseContext（），味精，Toast.LENGTH_SHORT）.show（）;
         }

         super.onPostExecute（结果）;
      }

}
 

解决方案

  

我应该通过上下文到AsyncTask的，当它被实例化，并建立从那里？

您没有选择，因为你将无法获得上下文通过任何其他方式。

I have a couple private AsyncTask methods that I'd like to break out into public external classes. In my application, I have a public class extending Application which holds some shared routines I want to access from different parts of my application. When I break out the AsyncTask class however, I'm no longer able to call getApplicationContext() to get a reference to my application library (the class does not inherit anything from Activity now). getBaseContext() will have problems as well. Should I be passing a context into the AsyncTask when it gets instantiated and build from there? Not sure if that was safe or not.

import java.util.ArrayList;
import android.os.AsyncTask;

public class dlTask extends AsyncTask
{
    long totalbytes = 0;
    long totalread = 0;
    ArrayList <String> data;

    @Override
    protected void onPreExecute ()
    {   
        AppLib lib = (AppLib) getApplicationContext();

        lib.saveStatusText ("Contacting " + lib.getServerAddress () + ":" + lib.getServerPort () + "...");
       super.onPreExecute ();
    }

      @Override
      protected Object doInBackground (Object... params)
      {
        data = lib.sendCommand (CMD_LIST);
         return true;
      }

      @Override
      protected void onPostExecute (Object result)
      {

         if (data != null)
         {
                    lib.saveStatusText (data.size () + " files found");
         }
         else
         {
            Log.d (TAG, "data is null");
            Toast.makeText (getBaseContext(), msg, Toast.LENGTH_SHORT).show ();                     
         }

         super.onPostExecute(result);
      }

}

解决方案

Should I be passing a context into the AsyncTask when it gets instantiated and build from there?

You do not have a choice, as you will be unable to get a Context by any other means.

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