Change the NavigationView's header title

Question

I have a NavigationView nested inside a DrawerLayout.

activity_main.xml

<android.support.v4.widget.DrawerLayout
android:id="@+id/drawer_layout"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">

.......

<android.support.design.widget.NavigationView
    android:id="@+id/navigation_view"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:layout_gravity="start"
    app:headerLayout="@layout/drawer_header"
    app:menu="@menu/drawer"/>
</android.support.v4.widget.DrawerLayout>

drawer_header.xml

<?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="150dp"
              android:background="?attr/colorPrimaryDark"
              android:gravity="bottom"
              android:orientation="vertical"
              android:padding="16dp"
              android:theme="@style/ThemeOverlay.AppCompat.Dark">

    <TextView
        android:id="@+id/drawerHeaderTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/drawer_header_text"
        android:textAppearance="@style/TextAppearance.AppCompat.Body1"/>

</LinearLayout>

How can I access the drawer header's title in Java code ? I tried to:

1. access it directly using its id (drawerHeaderTitle) but I get a NullPointerException

2. access it via the NavigationView.findViewById: same error

How can I overcome this problem ?

Answer 1

Using this approach

 mNavigationView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
            @Override
            public void onLayoutChange(View view, int i, int i1, int i2, int i3, int i4, int i5, int i6, int i7) {

                mNavigationView.removeOnLayoutChangeListener( this );

                TextView textView = (TextView) mNavigationView.findViewById(R.id.drawerHeaderTitle);

                textView.setText("title");
            }
        });

Answer 2

If you compile with 'com.android.support:design:23.1.1' you can access your header in this way:

private NavigationView mNavigation;
private View mHeaderView;

private TextView mDrawerHeaderTitle;

mNavigation = (NavigationView) findViewById(R.id.navigation_view);
mHeaderView = mNavigation.getHeaderView(0);

mDrawerHeaderTitle = (TextView) mHeaderView.findViewById(R.id.drawerHeaderTitle);

More info about this: http://developer.android.com/intl/es/tools/support-library/index.html