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Android fragment – findViewById returns null

Posted by: admin June 15, 2020 Leave a comment

Questions:

I have a problem that seems to be quite common on the internet : I have created an activity with just a fragment. This is the generated code:

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_customer);
        if (savedInstanceState == null) {
            getFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment()).commit();
            ListView lv = (ListView) findViewById(android.R.id.list);
        }
    }

After or inside the condition, I can’t get any object with findViewById: it is always null. Here is the rest of the generated code :

public static class PlaceholderFragment extends Fragment {

    public PlaceholderFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_customer,
                container, false);
        return rootView;
    }

activity_customer.xml:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.axacs.marc.CustomerActivity"
    tools:ignore="MergeRootFrame" />

the listview is actually in fragment_customer.xml:

<ListView
    android:id="@android:id/list"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_below="@+id/new_folder_button"
    android:text="" />

Does anyone know what is missing ?

How to&Answers:

use following after moving this line to onCreateView() if you want to use your listview in your fragment

ListView lv = (ListView)rootview.findViewById(android.R.id.list);