NullPointerException: name == null

Question

I'm developing an Android application that uses Fragments. I got this error.

Caused by: java.lang.NullPointerException: name == null

What does name == null mean? Here's the full log

08-04 15:02:22.422: E/AndroidRuntime(2499): FATAL EXCEPTION: main
08-04 15:02:22.422: E/AndroidRuntime(2499): java.lang.RuntimeException: Unable to start activity ComponentInfo{fi.peltoset.mikko.home/fi.peltoset.mikko.home.Koti}: android.view.InflateException: Binary XML file line #17: Error inflating class fragment
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.app.ActivityThread.access$600(ActivityThread.java:130)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.os.Handler.dispatchMessage(Handler.java:99)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.os.Looper.loop(Looper.java:137)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.app.ActivityThread.main(ActivityThread.java:4745)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at java.lang.reflect.Method.invokeNative(Native Method)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at java.lang.reflect.Method.invoke(Method.java:511)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at dalvik.system.NativeStart.main(Native Method)
08-04 15:02:22.422: E/AndroidRuntime(2499): Caused by: android.view.InflateException: Binary XML file line #17: Error inflating class fragment
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:704)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.view.LayoutInflater.rInflate(LayoutInflater.java:746)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:256)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.app.Activity.setContentView(Activity.java:1867)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at fi.peltoset.mikko.home.Koti.onCreate(Koti.java:13)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.app.Activity.performCreate(Activity.java:5008)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
08-04 15:02:22.422: E/AndroidRuntime(2499):     ... 11 more
08-04 15:02:22.422: E/AndroidRuntime(2499): Caused by: java.lang.NullPointerException: name == null
08-04 15:02:22.422: E/AndroidRuntime(2499):     at java.lang.VMClassLoader.findLoadedClass(Native Method)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at java.lang.ClassLoader.findLoadedClass(ClassLoader.java:354)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at java.lang.ClassLoader.loadClass(ClassLoader.java:491)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.app.Fragment.instantiate(Fragment.java:574)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.app.Fragment.instantiate(Fragment.java:552)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.app.Activity.onCreateView(Activity.java:4656)
08-04 15:02:22.422: E/AndroidRuntime(2499):     at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:680)
08-04 15:02:22.422: E/AndroidRuntime(2499):     ... 21 more

This is in a class called Navigation. It extends android.app.Fragment.

In it's onCreateView method I inflate the layout and return it. In the onActivityCreated method I check if the layout has two panes (I have different layouts for different devices) and based on that I add onClickListeners to these.

My code looks like this.

public class Navigation extends Fragment {
    private OnItemSelectedListener listener;
    private boolean dualPane = false;

    public interface OnItemSelectedListener {
        public void onMenuItemSelected(int fragmentId);
    }

    public void onAttach(Activity activity) {
        super.onAttach(activity);

        if(activity instanceof OnItemSelectedListener) {
            this.listener = (OnItemSelectedListener) activity;
        } else {
            ...
        }
    }

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.activity_navigation, container, false);

        return view;
    }

    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        View contentPane = getActivity().findViewById(R.id.contentFragment);
        dualPane = contentPane != null && contentPane.getVisibility() == View.VISIBLE;

        if(dualPane) {
            final ListView menu = (ListView) getActivity().findViewById(R.id.valikko);

            menu.setChoiceMode(ListView.CHOICE_MODE_SINGLE);

            String[] texts = new String[] {
                    ...
            };

            ArrayList<MenuItem> items = new ArrayList<MenuItem>();
            items.add(new MenuItem("Home", R.drawable.koti2));
            ...

            ImageArrayAdapter adapter = new ImageArrayAdapter(getActivity(), items, texts);
            menu.setAdapter(adapter);

            menu.setOnItemClickListener(new OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                    String item = ((TextView) view.findViewById(R.id.label)).getText().toString();

                    listener.onMenuItemSelected(0); // TODO ...
                }           
            });
        } else {
            ImageView btnYleiskatsaus   = (ImageView) getActivity().findViewById(R.id.btnYleiskatsaus);
            ...

            btnYleiskatsaus.setOnClickListener(onMenuClikkedListener);
            ...
        }       
    }

    private OnClickListener onMenuClikkedListener = new OnClickListener() {

        @Override
        public void onClick(View v) {           
            ...         
        }
    };
}

The layout file layout-sw720dp-land/activity_navigation.xml looks this

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/pressed_koti"
    android:orientation="vertical" >

    <ListView
        android:id="@+id/valikko"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" >
    </ListView>
</LinearLayout>

Here is the activity_koti.xml file.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >

    <fragment 
        android:id="@+id/menuFragment"
        android:layout_width="300dp"
        android:layout_height="match_parent"
        class="fi.peltoset.mikko.home.Navigation" />

    <fragment 
        android:id="@+id/contentFragment"
        android:layout_width="fill_parent"
        android:layout_height="match_parent" />
</LinearLayout>

I ran the application on an emulator with Android 4.1.2.

What causes these errors and how do I fix them?

I know what those are, but I'm wondering where that came from. Can't find it in the code... — MikkoP
– MikkoP, Commented Aug 6, 2013 at 14:11
What is at fi.peltoset.mikko.home.Koti.onCreate(Koti.java:13) it appears this is where your code is causing this in the stack trace — Robadob
– Robadob, Commented Aug 6, 2013 at 14:11
@Robadob It's the applications launcher Activity's onCreate method and on that line there is setContentView(R.layout.activity_koti); — MikkoP
– MikkoP, Commented Aug 6, 2013 at 14:13
You should check that in whichever XML file R.layout is stored that activity_koti is set correctly. If that is, check the acitivity_koti.xml for errors. — Robadob
– Robadob, Commented Aug 6, 2013 at 14:13

Community · Accepted Answer · 2017-05-23 12:18:33Z

6

You should use android:name to point to your fragments instead of class, it is also necessary to include the same attribute for your second fragment, this would explain the name==null.

Edit: Apparently class may be interchangeable with android:name, but I would follow what the docs use.

It should be;

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >

    <fragment 
        android:id="@+id/menuFragment"
        android:layout_width="300dp"
        android:layout_height="match_parent"
        android:name="fi.peltoset.mikko.home.Navigation" />

    <fragment 
        android:id="@+id/contentFragment"
        android:layout_width="fill_parent"
        android:layout_height="match_parent"
        android:name="I NEED A NAME" />
</LinearLayout>

http://developer.android.com/training/basics/fragments/creating.html#AddInLayout

edited May 23, 2017 at 12:18

CommunityBot

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answered Aug 6, 2013 at 14:17

Robadob

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1 Comment

MikkoP Over a year ago

Thanks for pointing out I need the android:name (or the class) attribute on the second fragment element too. That Element contains swappable content so I left it without it. Thanks to this post I replaced the second fragment with a LinearLayout and programmatically inserted the layout.

Geobits · Accepted Answer · 2013-08-06 14:18:27Z

1

When you add a fragment in the XML file, you need to give it a name attribute. That's why it says "name = null", because you're not doing that.

See the guide for adding Fragments for more.

answered Aug 6, 2013 at 14:18

Geobits

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Comments

Community · Accepted Answer · 2017-05-23 10:33:51Z

0

Try adding a class to your second fragment in activity_koti.xml if you're referencing it in your FragmentActivity.

Or, as Robadob says, add android:name:"your.path.YourName" to both.

Interesting additional info on class vs android:name in XML references to Fragments here.

edited May 23, 2017 at 10:33

CommunityBot

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answered Aug 6, 2013 at 14:18

Mena

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4 Comments

Robadob Over a year ago

The two (1, 2) android guide pages on fragments don't mention the class attribute, they use android:name for the function. On checking the docs page though, that uses class and not android:name.

Mena Over a year ago

@Robadob yes, and it actually works, I promise :) I've developed some fragments using class in the xml. Wasn't too sure it would apply because they were support fragments, but it doesn't seem to be relevant. See my edit for a link to the SO question on class vs android:name.

Robadob Over a year ago

I've already included the same link in my answer, read it then.

Mena Over a year ago

@Robadob oops - I read your comment and reacted before reading your answer again.

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