这些答案大部分似乎都过时了。Developer.android.com建议这样做:

科特林：

private fun hideSystemBars() {
    val windowInsetsController = ViewCompat.getWindowInsetsController(window.decorView) ?: return
    windowInsetsController.systemBarsBehavior = WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE
    windowInsetsController.hide(WindowInsetsCompat.Type.systemBars())
}

Java:

private void hideSystemBars() {
    WindowInsetsControllerCompat windowInsetsController = ViewCompat.getWindowInsetsController(getWindow().getDecorView());
    if (windowInsetsController == null) {
        return;
    }
    windowInsetsController.setSystemBarsBehavior(WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE);
    windowInsetsController.hide(WindowInsetsCompat.Type.systemBars());
}

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

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

活动:

@Override
public void onWindowFocusChanged(boolean hasFocus) {
        super.onWindowFocusChanged(hasFocus);
    if (hasFocus) {
        decorView.setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                | View.SYSTEM_UI_FLAG_FULLSCREEN
                | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);
    }
}

安卓清单：

 <activity android:name=".LoginActivity"
            android:configChanges="orientation|keyboardHidden|screenSize"
            android:label="@string/title_activity_login"
            android:theme="@style/FullscreenTheme"
            ></activity>

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);
}

在经历了很长时间的失败后，我想出了自己的解决方案，这与其他开发者的做法非常相似。所以如果有人需要她的话。我的问题是，系统导航栏没有隐藏后调用。在我的例子中，我需要横屏，所以为了以防万一，注释那一行。 首先，创建风格

    <style name="FullscreenTheme" parent="AppTheme">
    <item name="android:actionBarStyle">@style/FullscreenActionBarStyle</item>
    <item name="android:windowActionBarOverlay">true</item>
    <item name="android:windowBackground">@null</item>
    <item name="metaButtonBarStyle">?android:attr/buttonBarStyle</item>
    <item name="metaButtonBarButtonStyle">?android:attr/buttonBarButtonStyle</item>
</style>

这是我的舱单

<activity
        android:name=".Splash"
        android:screenOrientation="landscape"
        android:configChanges="orientation|keyboard|keyboardHidden|screenLayout|screenSize"
        android:label="@string/app_name"
        android:theme="@style/SplashTheme">

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

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

    <activity
        android:name=".MainActivity"
        android:configChanges="orientation|keyboard|keyboardHidden|screenLayout|screenSize"
        android:screenOrientation="landscape"
        android:label="@string/app_name"
        android:theme="@style/FullscreenTheme">
    </activity>

这是我的spalsh活动

public class Splash extends Activity {
/** Duration of wait **/
private final int SPLASH_DISPLAY_LENGTH = 2000;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    setContentView(R.layout.splash_creen);

    /* New Handler to start the Menu-Activity
     * and close this Splash-Screen after some seconds.*/
    new Handler().postDelayed(new Runnable(){
        @Override
        public void run() {
            /* Create an Intent that will start the Menu-Activity. */
            Intent mainIntent = new Intent(Splash.this,MainActivity.class);
            Splash.this.startActivity(mainIntent);
            Splash.this.finish();
        }
    }, SPLASH_DISPLAY_LENGTH);
}

}

这是我主要的全屏活动。onSystemUiVisibilityChange这个方法是退出重要的，否则android主导航栏在调用后将保持不变，不再消失。很烦人的问题，但是这个函数解决了这个问题。

公共类MainActivity扩展了AppCompatActivity ｛

private View mContentView;
@Override
public void onResume(){
    super.onResume();

    mContentView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE
            | View.SYSTEM_UI_FLAG_FULLSCREEN
            | View.SYSTEM_UI_FLAG_LAYOUT_STABLE
            | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
            | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
            | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);

}
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.fullscreen2);
    ActionBar actionBar = getSupportActionBar();
    if (actionBar != null)
    {
        actionBar.hide();
    }
    mContentView = findViewById(R.id.fullscreen_content_text);
    mContentView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE
            | View.SYSTEM_UI_FLAG_FULLSCREEN
            | View.SYSTEM_UI_FLAG_LAYOUT_STABLE
            | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
            | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
            | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);



    View decorView = getWindow().getDecorView();
    decorView.setOnSystemUiVisibilityChangeListener
            (new View.OnSystemUiVisibilityChangeListener()
            {
                @Override
                public void onSystemUiVisibilityChange(int visibility)
                {
                    System.out.println("print");

                    if ((visibility & View.SYSTEM_UI_FLAG_FULLSCREEN) == 0)
                    {
                        mContentView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE
                                | View.SYSTEM_UI_FLAG_FULLSCREEN
                                | View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                                | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
                                | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                                | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);
                    }
                    else
                    {

                        mContentView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE
                                    | View.SYSTEM_UI_FLAG_FULLSCREEN
                                    | View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                                    | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
                                    | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                                    | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);

                        }
                }
            });

}

}

这是我的启动画面布局:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <ImageView android:id="@+id/splashscreen" android:layout_width="wrap_content"
        android:layout_height="fill_parent"
        android:background="@android:color/white"
        android:src="@drawable/splash"
        android:layout_gravity="center"/>
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Hello World, splash"/>
</LinearLayout>

This is my fullscreen layout
    <?xml version="1.0" encoding="utf-8"?>
    <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#0099cc"
        >
        <TextView
            android:id="@+id/fullscreen_content_text"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:gravity="center"
            android:keepScreenOn="true"
            android:text="@string/dummy_content2"
            android:textColor="#33b5e5"
            android:textSize="50sp"
            android:textStyle="bold" />

    </FrameLayout>

我希望这对你有所帮助

 @Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    adjustFullScreen(newConfig);
}

@Override
public void onWindowFocusChanged(boolean hasFocus) {
    super.onWindowFocusChanged(hasFocus);
    if (hasFocus) {
        adjustFullScreen(getResources().getConfiguration());
    }
}
private void adjustFullScreen(Configuration config) {
    final View decorView = getWindow().getDecorView();
    if (config.orientation == Configuration.ORIENTATION_LANDSCAPE) {
        decorView.setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                        | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                        | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                        | View.SYSTEM_UI_FLAG_FULLSCREEN
                        | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);
    } else {
        decorView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_STABLE);
    }
}

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())
}