创建一个空活动，并在onCreate中添加两行。

public class MainActivity extends AppCompatActivity {

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

        // full screen activity
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
        getSupportActionBar().hide();

        setContentView(R.layout.activity_main);
    }
    ...
}

科特林

遵循谷歌文档，有一个简单的方法:

override fun onWindowFocusChanged(hasFocus: Boolean) {
super.onWindowFocusChanged(hasFocus)
if (hasFocus) hideSystemUI() }


private fun hideSystemUI() {
// Enables regular immersive mode.
// For "lean back" mode, remove SYSTEM_UI_FLAG_IMMERSIVE.
// Or for "sticky immersive," replace it with SYSTEM_UI_FLAG_IMMERSIVE_STICKY
window.decorView.systemUiVisibility = (View.SYSTEM_UI_FLAG_IMMERSIVE
        // Set the content to appear under the system bars so that the
        // content doesn't resize when the system bars hide and show.
        or View.SYSTEM_UI_FLAG_LAYOUT_STABLE
        or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
        or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
        // Hide the nav bar and status bar
        or View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
        or View.SYSTEM_UI_FLAG_FULLSCREEN)      }


// Shows the system bars by removing all the flags
// except for the ones that make the content appear under the system bars.
private fun showSystemUI() {
window.decorView.systemUiVisibility = 
(View.SYSTEM_UI_FLAG_LAYOUT_STABLE
        or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
        or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN)       }

谷歌文档

 @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);
    }
}

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

getWindow().addFlags(View.SYSTEM_UI_FLAG_LAYOUT_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>