Android Refreshing Fragment View after AsyncTask

问题:

I am trying to update list fragment when an AsyncTask in my activity completes but I am not sure if I am doing something wrong. Currently, I have a button that initiates the AsyncTask:

search = (Button)findViewById(R.id.search);
    search.setOnClickListener(
            new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    String productname = prodname.getText().toString().trim();
                    if (NetworkManager.isOnline(getApplicationContext())){
                        // Go to Other screen
                        AsyncFetcher results = new AsyncFetcher(currActivity);
                        String _url = "http://192.168.1.3:3000/search.json?
                                       utf8=%E2%9C%93&q="+productname;
                        // progressDialog = ProgressDialog.show(
                        //    ClassifiedsActivity.this, "", "Loading...");
                        results.execute(_url);
                    } else {
                        // Throw some warning saying no internet 
                        // connection was found
                    }
                }
            });

Once my execute is finished I have following to instantiate fragment within my activity:

ResultFragment resultfrag = new ResultFragment();
getSupportFragmentManager().beginTransaction()
                           .replace(R.id.content_frame, resultfrag).commit();

However it doesnt seem to replace my content with the list fragment. Here is my layout file:

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

回答1:

First replacing a fragment is nothing like refreshing it. Yes, it reloads every view in it and data as well. But you have to relate it with your new data. So i would recomment you to create a refresh method in your fragment and send this method your refreshed data, then notify your adapter as dataSetChanged.

To achieve this, you're gonna need to reach your currently attached fragment and call its refresh method. You can use findFragmentByTag to reach it out.

Edit: To clarify little bit more

When your AsyncTask is done, you should do something like this onPostExecute method:

ResultFragment resultFrag = (ResultFragment) getSupportFragmentManager()
                                 .findFragmentByTag("FragToRefresh");
if (resultFrag != null) {
    resultFrag.refreshData(refreshedArray);
}

And in your ResultFragment you need to have refreshData method, which is something like this:

public void refreshData(ArrayList<YourObject> data) {
   yourArray = new ArrayList<YourObject>(data);
   yourAdapter.notifyDataSetChanged();
}

And your list will be refreshed whenever your task is done.