Custom Layout in Preference gives Nullpointerexception

Question

I'm using a custom layout from a preference:

<PreferenceCategory
    android:title="Intolleranze">
    <Preference android:layout="@layout/intolerance_settings" />

</PreferenceCategory>

Layout:

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

<EditText
    android:id="@+id/editTextIntolerance"
    android:layout_width="200dp"
    android:layout_height="wrap_content"
    android:layout_margin="16dp"
    android:hint="Aggiungi intolleranza..." />


<Button
    android:id="@+id/addIntoleranceButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_margin="16dp"
    android:background="@drawable/oval_button"
    android:text="@string/add"
    android:textColor="@android:color/white"
    style="?android:attr/borderlessButtonStyle"/>

</LinearLayout>

When I try to add an OnClick Listener from the Preference Fragment I get a NullPointerException, because I cannot get a reference to the custom layout I set in the PreferenceScreen. How can I solve that ?

PreferenceFragment:

public class SettingsFragment extends PreferenceFragment {
    private Set<String> set;
    private Set<String> in;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.preferences);
    }

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = super.onCreateView(inflater, container, savedInstanceState);
    getActivity().setTitle("Impostazioni");
    return view;
}

@Override
public void onViewCreated(View view, Bundle savedIstanceState){

    Button addBtn = (Button) findViewById(R.id.addIntoleranceButton);
    final EditText editText = (EditText) findViewById(R.id.editTextIntolerance);
    addBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
           //NullPointerException
         }
    });
}

I know what a NullPointerException is. I'm asking how to avoid it in this particular case. — Cosimo Sguanci, Apr 16 '17 at 08:56

score 0 · Answer 1 · edited May 23 '17 at 12:32

Try using the associated view to get the id:

 Button addBtn = (Button) view.findViewById(R.id.addIntoleranceButton);

in your onViewCreated(View view, Bundle savedIstanceState)

EDIT

Move your code to onCreateView() and inflate the custom layout:

  @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.intolerance_settings, container, false);
        Button addBtn = (Button) rootView.findViewById(R.id.addIntoleranceButton);
        final EditText editText = (EditText) rootView.findViewById(R.id.editTextIntolerance);
        addBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

             }
        });
        return rootView;
    }

If that's also not work you can use PreferenceScreen check the answer Here

I have edited the answer... – rafsanahmad007 Apr 16 '17 at 09:18 — rafsanahmad007, Apr 16 '17 at 09:18

Ferdous Ahamed · Answer 2 · 2017-04-16T10:07:15.150

In onCreateView(), use:

View view = inflater.inflate(R.layout.intolerance_settings, container, false);

instead of

View view = super.onCreateView(inflater, container, savedInstanceState);

Move Button, EditText initialization and onClick listener code to onCreateView().

Update your PreferenceFragment as below:

public class SettingsFragment extends PreferenceFragment {
    private Set<String> set;
    private Set<String> in;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.preferences);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.intolerance_settings, container, false);     
        getActivity().setTitle("Impostazioni");

        Button addBtn = (Button) view.findViewById(R.id.addIntoleranceButton);
        final EditText editText = (EditText) view.findViewById(R.id.editTextIntolerance);
        addBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                 //Do something
            }
        });

        return view;
    }

    @Override
    public void onViewCreated(View view, Bundle savedIstanceState){

    }
}

Custom Layout in Preference gives Nullpointerexception

2 Answers2