AsyncTask传递自定义对象

Question

[我有一个自定义的parcelable对象车]

我看过AsyncTask但是关于这个主题还不太清楚:

我想将一个String(它是Vehicle的Vehicle ID)传递给AsyncTask,然后在doInBackground()中我有一个方法

mRemoteInterface.getTrackHistory();

这给了我一个ArrayList.我想在onPostExecute()中启动一个活动,其中Vehicle ID和ArrayList都是额外的.

这是我无法做到的概述.问题是我不明白将对象INTO到asynctask,然后从doInBackground()到onPostExecute()和从onPostExecute()返回到原始的执行调用.

getTrackHistory.execute(这里应该去哪里？);

private class getTrackHistory extends
AsyncTask<String, Integer, Boolean **WHAT SHOULD GO HERE?**> {

    @Override
    protected Boolean doInBackground(
            String... params) {
        try {
            String vehicleID = params[0];
            listVehicleHistory = (ArrayList<Vehicle>) mRemoteInterface.getVehicleHistory(vehicleID);
        } catch (Exception e) {

            e.printStackTrace();
        }


    }




    @Override
    protected void onProgressUpdate(Integer... progress) {

    }

    @Override
    protected void onPostExecute(Boolean worked) {

        super.onPostExecute(worked);

        Intent intent = new Intent(MainActivity.this,VehicleInfo.class);

        intent.putExtra("Vehicle ID", toReturn);
        intent.putParcelableArrayListExtra("VehicleHistory", listVehicleHistory);

        startActivity(intent);
    }

}

Answer 1

您可以将字符串传递给asynctask或doInbackground的构造函数

   new getTrackHistory(mystringvalue).execute();

然后在构造函数中

  private class getTrackHistory extends AsyncTask<String, Integer, Boolean> {  

  String value; 
  public getTrackHistory(String mystring) {
      value = mystring;
  }

AsyncTask {

   new TheTask().execute("mystring");
   class TheTask extends AsyncTask <String,Void,Void> { 
     @Override
     protected void onPreExecute() {
       super.onPreExecute();
     }
     @Override
     protected void onPostExecute(Void result) {
      super.onPostExecute(result);
     }
     @Override
     protected Void doInBackground(String... params) {
      String value = params[0];
     return null;
     }
   }

编辑:

您还可以将值传递给 doInbackground()

  new getTrackHistory(mystringvalue,ActivityName.this).execute();

关于评论中的问题

  String value; 
  TheInterface listener;
  public getTrackHistory(String mystring,Context context) {
      value= mystring;
      listener = (TheInterface) context; 
  }

在构造函数中

public interface TheInterface {

public void theMethod(ArrayList<String> result); // your result type

}

接口

if (listener != null) {
  listener.theMethod(result); // result is the ArrayList<String>
  // result returned in doInbackground 
  // result of doInbackground computation is a parameter to onPostExecute 
}

然后

在doInbackground中返回结果.我假设它的StringList类型为String.将arraylist更改为适合您的要求.

在你的onPostExecute中

  public class ActivityName implements getTrackHistory.TheInterface

在您的活动类中实现接口

 @Override
 public void theMethod(ArrayList<String> result) { // change the type of result according yo your requirement
 // use the arraylist here
 }

然后

   new getTrackHistory(mystringvalue).execute();

类似帖子使用界面

Android Parse JSON卡在get任务上.