How to pass ArrayAdapter from Activity to Fragment

Question

I have an app with 1 Activity and 3 Fragments.

In the Activity I have an adapter, into which I store log messages -

MainActivity.java (keeps the adapter with strings):

private ArrayAdapter<String> mLogListAdapter;

public void onCreate(Bundle savedInstanceState) {
     .....
    mLogListAdapter = new ArrayAdapter<String>(this,
                      android.R.layout.simple_list_item_1,
                      android.R.id.text1);

    if (savedInstanceState == null) {
        MainFragment fragment = new MainFragment();
        Bundle bundle = new Bundle();
        bundle.putSerializable("LOG", (Serializable) mLogListAdapter);
        //bundle.putParcellable("LOG", (Parcellable) mLogListAdapter);
        getFragmentManager().beginTransaction()
            .replace(R.id.root, fragment, "main")
            .commit();
    }
}

And I would like to use that adapter in my first fragment -

MainFragment.java (should display a list with log strings):

private ListView mLogList;

public View onCreateView(LayoutInflater inflater, 
        ViewGroup container,
        Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.activity_main, container, false);
    .........       
    mLogList = (ListView) view.findViewById(R.id.logList);
    mLogList.setChoiceMode(ListView.CHOICE_MODE_NONE);

    // THIS DOES NOT WORK
    ListAdapter adapter = 
        (ListAdapter) savedInstanceState.getSerializable("LOG");
    mLogList.setAdapter(adapter);

    return view;
}

Unfortunately, this does not work (app crashes).

I have also tried adding a public method to the Fragment and calling it in the Activity - but then mLogList is null and I get NPE (as the mLogList is created later - not in the constructor, but in onCreateView method):

MainActivity.java:

    if (savedInstanceState == null) {
        MainFragment fragment = new MainFragment();
        fragment.setAdapter(mLogListAdapter);
        getFragmentManager().beginTransaction()
            .replace(R.id.root, fragment, "main")
            .commit();
    }

MainFragment.java:

    public void setAdapter(ListAdapter adapter) {
        mLogList.setAdapter(adapter); // GIVES NPE
    }

Please advise how to pass my adapter to the Fragment.

UPDATE:

I've tried Exception Lover's suggestion (thanks +1), but get this error:

The method putParcelableArrayList(String, ArrayList) in the type Bundle is not applicable for the arguments (String, ArrayAdapter)

And I am not, sure which of the quickfix suggestions should I take:

Eclipse screenshot

Also I wonder, why can't savedInstanceState be used - do I really need to create a new Bundle object when passing data from Activity to Fragment?

you can pass it in constructor of fragment, and assign to the variable. — Satty, Apr 14 '15 at 16:00

score 1 · Answer 1 · answered Apr 14 '15 at 16:41

MainActivity.java (keeps the adapter with strings) change code

private ArrayAdapter<String> mLogListAdapter;

public void onCreate(Bundle savedInstanceState) {
     .....
    mLogListAdapter = new ArrayAdapter<String>(this,
                      android.R.layout.simple_list_item_1,
                      android.R.id.text1);

    if (savedInstanceState == null) {
        MainFragment fragment = new MainFragment();
        Bundle bundle = new Bundle();
        bundle.putParcelableArrayList("arraylist", data);
        fragment.setArguments(bundle);
        getFragmentManager().beginTransaction()
            .replace(R.id.root, fragment, "main")
            .commit();
    }
}

And also change

public View onCreateView(LayoutInflater inflater, 
        ViewGroup container,
        Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.activity_main, container, false);
    .........        
    mLogList = (ListView) view.findViewById(R.id.logList);
Bundle extras = getArguments();
if (extras != null) {
    data = extras.getParcelableArrayList("arraylist");
    mLogList.setAdapter(new MyAdapter(getActivity(), data));
}
    mLogList.setChoiceMode(ListView.CHOICE_MODE_NONE);


    return view;
}

Thanks, but I get an error in the Activity - please see the updated question — Alexander Farber, Apr 15 '15 at 11:04

How to pass ArrayAdapter from Activity to Fragment

1 Answers1