从 child 任务返回后执行后台任务时出错

Question

我不确定我是否完全理解从 child activity 返回后需要做什么来检索数据。我不需要将数据传递给 parent activity。我使用了 this for reference, they do mention onPause and onResume as well as possible solutions but should I use saved preferences instead of onSaveInstanceState and onRestoreInstanceState? It fails at the background task of checking the boolean. I also used this this 以获得进一步的帮助。

代码如下：

@Override 
public void onSaveInstanceState(Bundle savedInstanceState) {
    super.onSaveInstanceState(savedInstanceState);
    // Save UI state changes to the savedInstanceState.
    // This bundle will be passed to onCreate if the process is
    // killed and restarted.
    savedInstanceState.putString("type",type);
}

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    // Restore UI state from the savedInstanceState.
    // This bundle has also been passed to onCreate.
    super.onRestoreInstanceState(savedInstanceState);
    type = savedInstanceState.getString("type");
}

public class getFeed extends AsyncTask<String, Void, Void>{
    @Override
    protected Void doInBackground(String... strings) {
        ParseQuery<ParseObject> contentFeed = new ParseQuery<>("UserCommentary");
        if(type.equals("object1")){
            //Query for object1
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }
    else if(type.equals("object2")){
        //Query for object2
    }

    return null;
}

@Override
protected void onPostExecute(Void aVoid) {
    super.onPostExecute(aVoid);
    mySwipeRefreshLayout.setRefreshing(false);
    commentary.setAdapter(vCommentDetailAdapter);
    vCommentDetailAdapter.notifyDataSetChanged();
}

编辑：向代码添加了更多信息

Answer 1

事后看来，您的评论是 getFeed AsyncTask 正在 onCreate() 中执行。

你基本上是调用得太早了。请参阅 here 了解 Android Activity 生命周期。

onCreate() / onStart() 在 onRestoreInstanceState() 之前被调用。所以把任务的执行放在你的onResume()方法中。

Answer 2

我发现这个 solution 完成了我需要的，不需要保存数据和重新加载数据。

从 child 任务返回后执行后台任务时出错

Error on doing a background task after returning from child task

java

android

android-savedstate