如何永久隐藏导航栏

Question

如果我长按应用程序关闭的按钮，如何永久隐藏导航栏，否则应用程序处于全视图模式，没有导航栏隐藏从上到下滑动

Answer 1

https://developer.android.com/about/versions/android-4.0.html#SystemUI

(Controls for system UI visibility section) :

The SYSTEM_UI_FLAG_HIDE_NAVIGATION is a new flag that requests the navigation bar hide completely. Be aware that this works only for the navigation bar used by some handsets (it does not hide the system bar on tablets).

However, you could try to dim the system bar as done sometimes during gaming and video playback.

The SYSTEM_UI_FLAG_LOW_PROFILE flag replaces the STATUS_BAR_HIDDEN flag. When set, this flag enables “low profile" mode for the system bar or navigation bar. Navigation buttons dim and other elements in the system bar also hide. Enabling this is useful for creating more immersive games without distraction for the system navigation buttons.

Plz try this way

There are two ways to hide the navigation bar:

Way 1:

Touch “Settings” -> “Display” -> “Navigation bar” -> “Buttons” -> “Button layout”. Choose the pattern in “Hide navigation bar” -> When the app opens, the navigation bar will be automatically hidden and you can swipe up from the bottom corner of the screen to show it.

Way 2:

Touch “Settings” -> “Display” -> “Navigation bar” -> “Fullscreen gestures”. The navigation bar will be hidden and you will be shown “Gesture demos” to explain how to operate the “Go back”, “Go to Home screen” and “Open Recents” functions.

OR

Programetically

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

  <?xml version="1.0" encoding="utf-8"?>
  <androidx.constraintlayout.widget.ConstraintLayout
     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:layout_width="match_parent"
     android:layout_height="match_parent"
     tools:context=".MainActivity">
       <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hello World!"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
  </androidx.constraintlayout.widget.ConstraintLayout>

Step 3 − Add the following code to src/MainActivity.java

 import androidx.appcompat.app.AppCompatActivity;
 import android.annotation.SuppressLint;
 import android.os.Build;
 import android.os.Bundle;
 import android.view.View;

 public class MainActivity extends AppCompatActivity {

 private int currentApiVersion;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  currentApiVersion = android.os.Build.VERSION.SDK_INT;
  final int flags = 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;
  if (currentApiVersion >= Build.VERSION_CODES.KITKAT) {
     getWindow().getDecorView().setSystemUiVisibility(flags);
     final View decorView = getWindow().getDecorView();
     decorView.setOnSystemUiVisibilityChangeListener(new 
     View.OnSystemUiVisibilityChangeListener() {
        @Override
        public void onSystemUiVisibilityChange(int visibility) {
           if ((visibility & View.SYSTEM_UI_FLAG_FULLSCREEN) == 0) {
              decorView.setSystemUiVisibility(flags);
           }
          }
       });
     }
  }
  @SuppressLint("NewApi")
  @Override
  public void onWindowFocusChanged(boolean hasFocus) {
  super.onWindowFocusChanged(hasFocus);
  if (currentApiVersion >= Build.VERSION_CODES.KITKAT && hasFocus) {
     
   getWindow().getDecorView().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);
      }
   }
}

Step 4 − Add the following code to androidManifest.xml

       <?xml version="1.0" encoding="utf-8"?>
       <manifest xmlns:android="http://schemas.android.com/apk/res/android" 
           package="app.com.sample">
            <application
                android:allowBackup="true"
                android:icon="@mipmap/ic_launcher"
                android:label="@string/app_name"
                android:roundIcon="@mipmap/ic_launcher_round"
                android:supportsRtl="true"
                android:theme="@style/AppTheme">
          <activity android:name=".MainActivity">
                <intent-filter>
                      <action android:name="android.intent.action.MAIN" />
                      <category android:name="android.intent.category.LAUNCHER" />
                </intent-filter>
          </activity>
         </application>
    </manifest>