这是我的代码.我想知道当用户点击已经选中的标签时我怎么能检测到我想要在play.png和pause.png之间切换aPage的图标加上我也想在APage上调用一个方法.
public partial class MainPage : TabbedPage
{
public MainPage()
{
InitializeComponent();
var aPage = new NavigationPage(new APage())
{
Title = "Play",Icon = "play.png"
};
var bPage = new NavigationPage(new BPage())
{
Title = "Settings",Icon = "b.png"
};
Children.Add(aPage);
Children.Add(bPage);
}
}
请注意,如果可能,我想找到一个不涉及iOS和Android自定义渲染器的解决方案.我想知道我可以重新定义TabbedPage并将逻辑放在该类中吗？
解决方法
我知道您要避免使用自定义渲染器,但这只能通过使用自定义渲染器来实现.
码
Xamarin.Android自定义渲染器
using Android.Content;
using Android.Support.Design.Widget;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;
using Xamarin.Forms.Platform.Android.AppCompat;
[assembly: ExportRenderer(typeof(MainPage),typeof(MainPageRenderer))]
namespace YourNameSpace
{
public class MainPageRenderer : TabbedPageRenderer,TabLayout.IOnTabSelectedListener
{
MainPage _page;
public MainPageRenderer(Context context) : base(context) { }
protected override void OnElementChanged(ElementChangedEventArgs<TabbedPage> e)
{
base.OnElementChanged(e);
if (e.NewElement != null)
_page = e.NewElement as MainPage;
else
_page = e.OldElement as MainPage;
}
void TabLayout.IOnTabSelectedListener.OnTabReselected(TabLayout.Tab tab)
{
System.Diagnostics.Debug.WriteLine("Tab Reselected");
//Handle Tab Reselected
}
}
}
Xamarin.iOS自定义渲染器
using System;
using System.Diagnostics;
using UIKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;
[assembly: ExportRenderer(typeof(MainPage),typeof(MainPageRenderer))]
namespace YourNameSpace
{
public class MainPageRenderer : TabbedRenderer
{
MainPage _page;
protected override void OnElementChanged(VisualElementChangedEventArgs e)
{
base.OnElementChanged(e);
if (e.NewElement != null)
_page = e.NewElement as MainPage;
else
_page = e.OldElement as MainPage;
try
{
if (ViewController is UITabBarController tabBarController)
tabBarController.ViewControllerSelected += OnTabbarControllerItemSelected;
}
catch (Exception exception)
{
Debug.WriteLine(exception);
}
}
void OnTabbarControllerItemSelected(object sender,UITabBarSelectionEventArgs eventArgs)
{
if (_page?.CurrentPage?.Navigation != null && _page.CurrentPage.Navigation.NavigationStack.Count > 0)
{
Debug.WriteLine("Tab Tapped");
//Handle Tab Tapped
}
}
}
}
