Immersive mode navigation becomes sticky after volume press or minimise-restore

问题

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        this.getWindow().getDecorView().setSystemUiVisibility(getSystemUiFlags());
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    private static int getSystemUiFlags() {
            return View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
                    | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                    | View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                    | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                    | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION;
    }

}

After first start

After volume buttons pressed or after recent apps pressed twice

I saw QuickPic app doesn\'t have this bug. I wonder how they omitted it.

回答1:

The following code works for me:

public void updateUI() {
    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(
                        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);
                }
            }
        });
}

And called the listener on onCreate and onResume methods:

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

@Override
public void onResume() {
    super.onResume();
    updateUI();
}

回答2:

My solution is to set the UI-Visibility flags in three places:

1. When getting the focus
2. In onResume
3. In the OnSystemUiVisibilityChangeListener listener

The third solved my problem. The others might not be needed, but I left them. This is what is looks like:

  private void setupMainWindowDisplayMode() {
    View decorView = setSystemUiVisilityMode();
    decorView.setOnSystemUiVisibilityChangeListener(new OnSystemUiVisibilityChangeListener() {
      @Override
      public void onSystemUiVisibilityChange(int visibility) {
        setSystemUiVisilityMode(); // Needed to avoid exiting immersive_sticky when keyboard is displayed
      }
    });
  }

  private View setSystemUiVisilityMode() {
    View decorView = getWindow().getDecorView();
    int options;
    options =
        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 // hide nav bar
      | View.SYSTEM_UI_FLAG_FULLSCREEN // hide status bar
      | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;

    decorView.setSystemUiVisibility(options);
    return decorView;
  }

setupMainWindowDisplayMode() gets called in onCreate().

回答3:

I had the same problem, and I solved it with a simple workaround. Even though I couldn't find the theoretical reason of this workaround, but it worked for me anyway.

It seems like when a volume button is pressed, the 'flags' related to the 'immersive mode' are cleared. And I think that's why the immersive mode is disabled and the immersive mode is not restored automatically.

Therefore, I tried to set the 'flags' after pressing the volume button with 'runnable' object.

So, it works like this:

immersive mode -> volume button pressed(flags cleared) -> 500ms later, the runnable object sets the flags again -> immersive mode restored

1. First, define the runnable object to set the flags

private Runnable decor_view_settings = new Runnable()
{
    public void run() 
    {
        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);
    }
};

2. Post the runnable object with some delay to a handler when a volume button is pressed

private Handler mHandler = new Handler();

...

@Override 
public boolean onKeyDown(int keyCode, KeyEvent event) 
{
    if(keyCode == KeyEvent.KEYCODE_BACK)
    {
        finish();
    }
    else if(keyCode == KeyEvent.KEYCODE_VOLUME_DOWN || keyCode == KeyEvent.KEYCODE_VOLUME_UP)
    {
        mHandler.postDelayed(decor_view_settings, 500);
    }

    return super.onKeyDown(keyCode, event);
}

I just delayed it for 500ms with no reason, it's not important.

3. The basic code for immersive mode with runnable object

@Override
public void onWindowFocusChanged(boolean hasFocus) 
{
    super.onWindowFocusChanged(hasFocus);

    if(hasFocus) 
    {
        mHandler.post(decor_view_settings);
    }
}

It worked perfectly on my app.

So, when I press a volume button, the immersive mode is disabled and the volume rocker pops up.

after a few seconds, the volume rocker disappears and so does the status bar and the navigation bar.

Hope this work for you.

来源：https://stackoverflow.com/questions/21164836/immersive-mode-navigation-becomes-sticky-after-volume-press-or-minimise-restore