Android Api 23 Navigationsansicht ändern headerLayout textview

Ich teste das Beispielprojekt für die Navigationsleiste in Android und habe ein Problem beim Festlegen des Texts in der Kopfzeile des Navigationsansichtsprofils.

Das ist mein Code:

MainActivity.java

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.syncState();

    NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);

    TextView text = (TextView) findViewById(R.id.textView);
    texto.setText("HELLO");
}

Aktivität_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools" android:id="@+id/drawer_layout"
android:layout_width="match_parent" android:layout_height="match_parent"
android:fitsSystemWindows="true" tools:openDrawer="start">

<include layout="@layout/app_bar_main" android:layout_width="match_parent"
    android:layout_height="match_parent" />

<android.support.design.widget.NavigationView android:id="@+id/nav_view"
    android:layout_width="wrap_content" android:layout_height="match_parent"
    android:layout_gravity="start" android:fitsSystemWindows="true"
    app:headerLayout="@layout/nav_header_main" app:menu="@menu/activity_main_drawer" />

</android.support.v4.widget.DrawerLayout>

nav_header_main.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="@dimen/nav_header_height"
android:background="@drawable/side_nav_bar"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:theme="@style/ThemeOverlay.AppCompat.Dark" android:orientation="vertical"
android:gravity="bottom">

<ImageView android:layout_width="wrap_content" android:layout_height="wrap_content"
    android:paddingTop="@dimen/nav_header_vertical_spacing"
    android:src="https://stackoverflow.com/questions/33199764/@android:drawable/sym_def_app_icon" android:id="@+id/imageView" />

<TextView android:layout_width="match_parent" android:layout_height="wrap_content"
    android:paddingTop="@dimen/nav_header_vertical_spacing" android:text="Android Studio"
    android:textAppearance="@style/TextAppearance.AppCompat.Body1" />

<TextView android:layout_width="wrap_content" android:layout_height="wrap_content"
    android:text="[email protected]" android:id="@+id/textView" />

</LinearLayout>

Wenn ich versuche, den Text der Textansicht zu setzen, bekomme ich immer diesen Fehler und es passiert nur mit API-Level 23:

java.lang.NullPointerException: Attempt to invoke virtual method   'void android.widget.TextView.setText(java.lang.CharSequence)' on a null   object reference

Wie kann ich den Textview-Text der nav_header_main.xml von der Hauptaktivität ändern??

Vielen Dank im Voraus

Mit der Version 23.1.1 der Design Support Library können Sie jetzt

View header = navigationView.getHeaderView(0)
TextView text = (TextView) header.findViewById(R.id.textView);

Ich hatte das gleiche Problem und konnte es mit diesem Code vermeiden:

    View header = LayoutInflater.from(this).inflate(R.layout.nav_header_main, null);
    navigationView.addHeaderView(header);
    TextView text = (TextView) header.findViewById(R.id.textView);
    text.setText("HELLO");

Die Orium-Antwort funktioniert und dies wird auch funktionieren.

View header = navigationView.inflateHeaderView(R.layout.nav_header_main);
    TextView text = (TextView) header.findViewById(R.id.textView);
    texto.setText("HELLO");

das hat das problem bei mir gelöst

    View headerView = navigationView.inflateHeaderView(R.layout.header_view);

    txt_fullname = (TextView) headerView.findViewById(R.id.txt_fullname);
    txt_email = (TextView) headerView.findViewById(R.id.txt_email);

View headerView=navigationView.getChildAt(0);
TextView tvName=(TextView)hView.findViewById(R.id.name);
TextView tvEmail=(TextView)hView.findViewById(R.id.email);

    tvName.setText(data);
    tvEmail.setText(data);

Oder wenn Sie dieses Attribut verwenden:

<android.support.desibn.widget.NavigationView>
    ...
    app:headerLayout="@layout/your_header_layout"/>

Sie können:

View header = mNavigationView.getHeaderView(0);
TextView title = (TextView) header.findViewById(R.id.your_title_id);
//Or something else

Die obige Antwort ist richtig, aber in kotlin müssen Sie verwenden findViewById<View>

   val navigationHeader = navigation_view.getHeaderView(0)
        val navigationTitle = navigationHeader.findViewById<View>(R.id.txt_navigation_title) as TextView
        navigationTitle.text = "This is your header"