在AndroidManifest.xml文件:

<activity
    android:name=".Launch"
    android:label="@string/app_name"
    android:theme="@android:style/Theme.NoTitleBar.Fullscreen" > <!-- This line is important -->

    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>  

或者在Java代码中:

protected void onCreate(Bundle savedInstanceState){
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
}

如果你不想使用主题@android:style/ theme . notitlebar。因为你已经在使用你自己的主题，你可以使用android:windowFullscreen。

在AndroidManifest.xml:

<activity
  android:name=".ui.activity.MyActivity"
  android:theme="@style/MyTheme">
</activity>

在styles.xml:

<style name="MyTheme"  parent="your parent theme">
  <item name="android:windowNoTitle">true</item>
  <item name="android:windowFullscreen">true</item> 
</style>

getWindow () .setFlags (WindowManager.LayoutParams。FLAG_LAYOUT_NO_LIMITS WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);if (getSupportActionBar() != null){getSupportActionBar().hide();｝

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

对于安卓X

1. 透明状态栏

    window?.decorView?.systemUiVisibility = (View.SYSTEM_UI_FLAG_LAYOUT_STABLE
            or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN)
    window.statusBarColor = Color.TRANSPARENT

2. 透明的状态栏和底部导航栏

    window.setFlags(
        WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS,
        WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN
    );

3.隐藏状态栏

API 30+推荐的Compat解决方案(包括向后兼容性)

  val windowInsetsController =
      WindowCompat.getInsetsController(window, window.decorView) ?: return
  windowInsetsController.systemBarsBehavior =
      WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE
  windowInsetsController.hide(WindowInsetsCompat.Type.statusBars())

https://developer.android.com/training/system-ui/immersive

4. 隐藏状态栏和底部导航栏

消防级别30:

SystemUiVisibility标志已弃用。请改用WindowInsetsController。

和3一样。，只需使用WindowInsetsCompat.Type.systemBars()

    val actionBar: ActionBar? = supportActionBar
        if (actionBar != null) actionBar.hide()

    val windowInsetsController =
        WindowCompat.getInsetsController(window, window.decorView) ?: return
    windowInsetsController.systemBarsBehavior =
        WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE
    windowInsetsController.hide(WindowInsetsCompat.Type.systemBars())

https://developer.android.com/training/system-ui/immersive

把这些代码放在哪里?

   override fun onCreate(savedInstanceState: Bundle?) {

        /*  Put above code here ..... */
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_slider)
   }

Note

我在Pixel 3A模拟器中检查了这段代码 可能自定义android操作系统不支持 set style <style name="主题。"全屏Theme.MaterialComponents.DayNight.NoActionBar“父= >

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())
    }
}