Android：实现全屏 + 隐藏导航栏和虚拟按键

1. 将下面这段代码复制到public class MainActivity extends AppCompatActivity的最开始。

 /* 隐藏虚拟按键，并且全屏 */
    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    protected void hideBottomUIMenu() {
        //隐藏虚拟按键，并且全屏
        if (Build.VERSION.SDK_INT < 19) { // lower api
            View v = this.getWindow().getDecorView();
            v.setSystemUiVisibility(View.GONE);
            int uiOptions = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                    | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
                    | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                    | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                    | View.SYSTEM_UI_FLAG_FULLSCREEN
                    | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;
            v.setSystemUiVisibility(uiOptions);
        } else {
            //for new api versions.
            View decorView = getWindow().getDecorView();
            int uiOptions = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                    | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
                    | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                    | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                    | View.SYSTEM_UI_FLAG_FULLSCREEN
                    | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;
            decorView.setSystemUiVisibility(uiOptions);
        }
    }

2. 在onCreate中的setContentView(R.layout.activity_main);语句之后复制这段代码即可。

Objects.requireNonNull(getSupportActionBar()).hide();   //隐藏导航栏
hideBottomUIMenu(); //隐藏虚拟键