向上滑动后如何拦截android底部导航栏的可见性

Question

My Xamarin.Android MVVMCross fragment implements View.IOnSystemUiVisibilityChangeListener
Here is fragment OnViewCreated method

View _decorview = ParentActivity.Window.DecorView;
_decorview.SetOnSystemUiVisibilityChangeListener(this);
var uiOptions =
                SystemUiFlags.HideNavigation |
                SystemUiFlags.ImmersiveSticky;
            _decorview.SystemUiVisibility = (StatusBarVisibility)uiOptions;

Here is an OnSystemUiVisibilityChange method:

public void OnSystemUiVisibilityChange([GeneratedEnum] StatusBarVisibility visibility)
        {
            if (((int)visibility & (int)SystemUiFlags.HideNavigation) == 0)
            {
                if (ParentActivity.BottomNavigation != null)
                    ParentActivity.BottomNavigation.Visibility = ViewStates.Gone;
            }
            else
            {
                if (ParentActivity.BottomNavigation != null)
                    ParentActivity.BottomNavigation.Visibility = ViewStates.Visible;
            }
        }

But this method doesn't calls when I swipe up to show navigation bar

Answer 1

标记SystemUiFlags.ImmersiveSticky防止在系统 UI 可见性更改时接收回调

Answer 2

AlexTsy.

I agree that the documentation states ImmersiveSticky prevents receiving the callback.

However, when I moved to Android 10 I had problems with all my StickyImmersive screens on rotation. There would be spurious system bar reappearances. Not every rotation, but rotate enough times and they would start appearing. All these screens worked fine with Android 9 and lower and still do without the callback, but any Android 10 device needs the callback. In desperation, I tried adding a View.IOnSystemUiVisibilityChangeListener to the fragment and that fixed it. The additional code didn't have any adverse effect on the devices with Android 9 or less.