如何在NavigationView中的textView中设置文本

Question

我在textview中设置文本时收到空指针异常.textview位于仪表板活动的导航视图中.

在主要活动中,我试图设置这样的文字:

public class Dashboard extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {
protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_dashboard);
        TextView StudentNameView = (TextView) navigationView.findViewById(R.id.studentName);
        StudentNameView.setText("Test");
}
}

这是我的仪表板活动的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_dashboard" 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_dashboard"
        app:menu="@menu/activity_dashboard_drawer" />

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

我的导航标题菜单是

<?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">



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

    <TextView android:layout_width="wrap_content" android:layout_height="wrap_content"
        android:text="" android:id="@+id/studentEmail" />

</LinearLayout>

Answer 1

更重要的是使用lib版本v7:23.1.1使用compile'c​​om.android.support:appcompat-v7:23.1.1'

在你的代码中写下面的行

NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
View v = navigationView.getHeaderView(0);
TextView avatarContainer = (TextView ) v.findViewById(R.id.imgAvatar);