如何使用TabbedPage.ToolbarPlacement ="Bottom"实现TabLayout.IOnTabSelectedListener.OnTabUnselected - Xamarin Forms？

Question

我刚刚用过android:TabbedPage.ToolbarPlacement="Bottom".我曾经有以下代码:

void TabLayout.IOnTabSelectedListener.OnTabUnselected(TabLayout.Tab tab)
{
   var playPage = Element.CurrentPage as NavigationPage;
   if (!(playPage.RootPage is PhrasesFrame))
      return;

   var tabLayout = (TabLayout)ViewGroup.GetChildAt(1);
   var playTab = tabLayout.GetTabAt(4);
   tab.SetText("Play");
   tab.SetIcon(Resource.Drawable.ionicons_2_0_1_play_outline_25);
   App.pauseCard = true;
}

任何人都知道如何实现这一点ToolbarPlacement="Bottom"？我已经实现了两者BottomNavigationView.IOnNavigationItemSelectedListener,BottomNavigationView.IOnNavigationItemReselectedListener但是UnselectedTab如果有的话,找不到任何参考.

编辑:

以前的自定义渲染器使用默认选项卡位置并实现TabLayout:

namespace Japanese.Droid
{
    public class MyTabbedPageRenderer: TabbedPageRenderer, TabLayout.IOnTabSelectedListener
    {
        ViewPager viewPager;
        TabLayout tabLayout;
        bool setup;

        public MyTabbedPageRenderer(Context context): base(context){ }

        protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            // More codes here
        }

        void TabLayout.IOnTabSelectedListener.OnTabReselected(TabLayout.Tab tab)
        {
            UpdateTab(tab);
        }

        void TabLayout.IOnTabSelectedListener.OnTabSelected(TabLayout.Tab tab)
        {
            UpdateTab(tab);
        }

        void TabLayout.IOnTabSelectedListener.OnTabUnselected(TabLayout.Tab tab)
        {
            var playPage = Element.CurrentPage as NavigationPage;
            if (!(playPage.RootPage is PhrasesFrame))
                return;

            var tabLayout = (TabLayout)ViewGroup.GetChildAt(1);
            var playTab = tabLayout.GetTabAt(4);
            tab.SetText("Play");
            tab.SetIcon(Resource.Drawable.ionicons_2_0_1_play_outline_25);
            App.pauseCard = true;
        }

        void UpdateTab(TabLayout.Tab tab) 
        {
            // To have the logic only on he tab on position 1
            if (tab == null || tab.Position != 4)
            {
                return;
            }

            if (tab.Text == "Play")
            {
                tab.SetText("Pause");
                tab.SetIcon(Resource.Drawable.ionicons_2_0_1_pause_outline_22);
                App.pauseCard = false;
            }
            else
            {
                tab.SetText("Play");
                tab.SetIcon(Resource.Drawable.ionicons_2_0_1_play_outline_25);
                App.pauseCard = true;
            }
        }
    }
}

当前自定义渲染器使用ToolbarPlacement="Bottom":

namespace Japanese.Droid
{
    public class BottomTabPageRenderer : TabbedPageRenderer, BottomNavigationView.IOnNavigationItemSelectedListener, BottomNavigationView.IOnNavigationItemReselectedListener
    {
        public BottomTabPageRenderer(Context context) : base(context) { }

        protected override void OnElementChanged(ElementChangedEventArgs<TabbedPage> e)
        {
            base.OnElementChanged(e);

            // More codes here
        }

        bool BottomNavigationView.IOnNavigationItemSelectedListener.OnNavigationItemSelected(IMenuItem item)
        {
            base.OnNavigationItemSelected(item);

            UpdateTab(item)
        }

        void BottomNavigationView.IOnNavigationItemReselectedListener.OnNavigationItemReselected(IMenuItem item)
        {
            UpdateTab(item);
        }

        void UpdateTab(IMenuItem item)
        {
            var playTabId = 4;

            var title = item.TitleFormatted.ToString();
            if (item == null || item.ItemId != playTabId)
            {
                return;
            }

            if (item.ItemId == playTabId)
            {
                if (title == "Play")
                {
                    item.SetTitle("Pause");
                    item.SetIcon(Resource.Drawable.ionicons_2_0_1_pause_outline_22);
                    App.pauseCard = false;
                }
                else
                {
                    item.SetTitle("Play");
                    item.SetIcon(Resource.Drawable.ionicons_2_0_1_play_outline_25);
                    App.pauseCard = true;
                }
            }

        }

    }
}

所以现在我的问题是我不知道如何TabLayout.IOnTabSelectedListener.OnTabUnselected在新的自定义渲染器中实现它.

Answer 1

根据 G.Hakim 的建议，我能够通过捕获我想要处理的选项卡项并在 中执行必要的操作来完成我想做的事情BottomNavigationView.IOnNavigationItemSelectedListener.OnNavigationItemSelected。

namespace Japanese.Droid
{
    public class BottomTabPageRenderer : TabbedPageRenderer, BottomNavigationView.IOnNavigationItemSelectedListener, BottomNavigationView.IOnNavigationItemReselectedListener
    {
        // same as above

        bool BottomNavigationView.IOnNavigationItemSelectedListener.OnNavigationItemSelected(IMenuItem item)
        {
            base.OnNavigationItemSelected(item);

            if(item.ItemId == 4 && item.TitleFormatted.ToString() == "Play") 
            {
                item.SetTitle("Pause");
                item.SetIcon(Resource.Drawable.ionicons_2_0_1_pause_outline_22);
                App.pauseCard = false;
                playTab = item;
            } 

            if(item.ItemId !=4 && playTab.TitleFormatted.ToString() == "Pause") 
            {
                playTab.SetTitle("Play");
                playTab.SetIcon(Resource.Drawable.ionicons_2_0_1_play_outline_25);
                App.pauseCard = true;
            }
            return true;
        }

        // same as above

    }
}