Android Api 23 更改导航视图 headerLayout textview [英] Android Api 23 Change Navigation View headerLayout textview

问题描述

我正在 android 中测试 Navigation Drawer 示例项目，但在设置导航视图配置文件标题中的文本时遇到问题.

I am testing the Navigation Drawer sample project in android and i have a problem setting the text in navigation view profile header.

这是我的代码:

MainActivity.java

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");
}

activity_main.xml

activity_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

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="@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="[e-mail]" android:id="@+id/textView" />

</LinearLayout>

当我尝试设置 textview 的文本时，我总是收到此错误，并且仅在 api 级别 23 时发生:

When i try to set the text of the textview i always get this error and it only happens with api level 23:

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

如何从主活动更改 nav_header_main.xml 的 Textview 文本?

How can i change the Textview text of the nav_header_main.xml from the main activity??

提前致谢

推荐答案

我遇到了同样的问题，并且能够通过以下代码避免它:

I had the same issue and was able to avoid it with this code:

    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");

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