将此添加到styles.xml中

<item name="android:windowFullscreen">true</item>

的例子,

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="windowActionBar">false</item>
    <item name="windowNoTitle">true</item>
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="android:windowFullscreen">true</item>
    <item name="colorAccent">@color/colorAccent</item>
</style>

并更改AndroidManifest文件与波纹代码

android:theme="@style/AppTheme"

的例子,

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:theme="@style/AppTheme"
    android:supportsRtl="true">

AndroidManifest.xml

<activity ...
          android:theme="@style/FullScreenTheme"
    >
</activity>

I.你的主应用的主题是theme . appcompat . light . darkactionbar

隐藏ActionBar / StatusBar style.xml

<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
    ...
</style>

<style name="FullScreenTheme" parent="AppTheme">
    <!--this property will help hide the ActionBar-->
    <item name="windowNoTitle">true</item>
    <!--currently, I don't know why we need this property since use windowNoTitle only already help hide actionbar. I use it because it is used inside Theme.AppCompat.Light.NoActionBar (you can check Theme.AppCompat.Light.NoActionBar code). I think there are some missing case that I don't know-->
    <item name="windowActionBar">false</item>
    <!--this property is used for hiding StatusBar-->
    <item name="android:windowFullscreen">true</item>
</style>

隐藏系统导航栏

public class MainActivity extends AppCompatActivity {

    protected void onCreate(Bundle savedInstanceState) {
        getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);
        setContentView(R.layout.activity_main)
        ...
    }
 }

2你的主应用主题是theme . appcompat . light . noactionbar

隐藏ActionBar / StatusBar style.xml

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    ...
</style>

<style name="FullScreenTheme" parent="AppTheme">
    <!--don't need any config for hide ActionBar because our apptheme is NoActionBar-->
    <!--this property is use for hide StatusBar-->
    <item name="android:windowFullscreen">true</item> // 
</style>

隐藏系统导航栏

类似于theme。appcompat。light。darkactionbar。

演示

使用Android Studio(当前版本是2.2.2)很容易添加一个全屏活动。

请看步骤:

右键单击你的java主包，选择“新建”，选择“活动”，然后点击“全屏活动”。

自定义活动(“活动名称”，“布局名称”等)，点击“完成”。

完成了!

现在你有一个全屏的活动很容易(查看java类和活动布局，以了解事情是如何工作的)!

import androidx.core.view.WindowInsetsCompat.Type

fun Activity.fullscreen() {
    with(WindowInsetsControllerCompat(window, window.decorView)) {
        systemBarsBehavior = WindowInsetsControllerCompat.BEHAVIOR_SHOW_BARS_BY_SWIPE
        hide(Type.systemBars())
    }
}

fun Activity.exitFullscreen() {
    WindowInsetsControllerCompat(window, window.decorView).show(Type.systemBars())
}

从mozilla找到解决方案，他们在这里做了一个扩展库

如果链接中断，这里是代码

/**
 * Retrieves a {@link WindowInsetsControllerCompat} for the top-level window decor view.
 */
fun Window.getWindowInsetsController(): WindowInsetsControllerCompat {
    return WindowInsetsControllerCompat(this, this.decorView)
}


/**
 * Attempts to call immersive mode using the View to hide the status bar and navigation buttons.
 * @param onWindowFocusChangeListener optional callback to ensure immersive mode is stable
 * Note that the callback reference should be kept by the caller and be used for [exitImmersiveModeIfNeeded] call.
 */
fun Activity.enterToImmersiveMode(
    onWindowFocusChangeListener: ViewTreeObserver.OnWindowFocusChangeListener? = null
) {
    window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
    window.getWindowInsetsController().apply {
        hide(WindowInsetsCompat.Type.systemBars())
        systemBarsBehavior = WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE
    }

    // We need to make sure system bars do not become permanently visible after interactions with content
    // see https://github.com/mozilla-mobile/fenix/issues/20240
    onWindowFocusChangeListener?.let {
        window.decorView.viewTreeObserver?.addOnWindowFocusChangeListener(it)
    }
}

/**
 * Attempts to come out from immersive mode using the View.
 * @param onWindowFocusChangeListener optional callback to ensure immersive mode is stable
 * Note that the callback reference should be kept by the caller and be the same used for [enterToImmersiveMode] call.
 */
@Suppress("DEPRECATION")
fun Activity.exitImmersiveModeIfNeeded(
    onWindowFocusChangeListener: ViewTreeObserver.OnWindowFocusChangeListener? = null
) {
    if (WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON and window.attributes.flags == 0) {
        // We left immersive mode already.
        return
    }
    onWindowFocusChangeListener?.let {
        window.decorView.viewTreeObserver?.removeOnWindowFocusChangeListener(it)
    }
    window.clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
    window.getWindowInsetsController().apply {
        show(WindowInsetsCompat.Type.systemBars())
    }
}

你可以通过编程来实现:

public class ActivityName extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // remove title
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
            WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.main);
    }
}

或者你也可以通过AndroidManifest.xml文件来实现:

<activity android:name=".ActivityName"
    android:label="@string/app_name"
    android:theme="@android:style/Theme.NoTitleBar.Fullscreen"/>

编辑:

如果你正在使用AppCompatActivity，那么你需要添加新的主题

<style name="Theme.AppCompat.Light.NoActionBar.FullScreen" parent="@style/Theme.AppCompat.Light.NoActionBar">
    <item name="android:windowNoTitle">true</item>
    <item name="android:windowActionBar">false</item>
    <item name="android:windowFullscreen">true</item>
    <item name="android:windowContentOverlay">@null</item>
</style>

然后使用它。

<activity android:name=".ActivityName"
    android:label="@string/app_name"
    android:theme="@style/Theme.AppCompat.Light.NoActionBar.FullScreen"/>

感谢https://stackoverflow.com/a/25365193/1646479