Question

我创建了一个自定义导航页面来处理后退导航按钮事件。

Click侦听器已正确连接到工具栏，但是由于某种原因更改方向后，不会以某种方式触发OnClick事件。在更改方向之前，它可以正常工作。谁能帮我解决这个问题？我已经尝试了好几个星期。

using Android.Content;
using Android.Support.V7.Widget;
using Android.Support.V4.Widget;
using Android.Views;
using Android.Util;

using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;
using Xamarin.Forms.Platform.Android.AppCompat;

using RichyInspect.Renderers;
using RichyInspect.Droid.Renderers;
using Android.Content.Res;

[assembly: ExportRenderer(typeof(VNavigationPage), typeof(VNavigationPage_Android))]
namespace RichyInspect.Droid.Renderers
{
    // Source: https://forums.xamarin.com/discussion/87795/onoptionsitemselected-not-invoked-using-masterdetails-page-on-android
    public class VNavigationPage_Android : NavigationPageRenderer
    {
        public VNavigationPage_Android(Context context) : base(context)
        {
            AutoPackage = false;
        }

        protected override void OnConfigurationChanged(Configuration newConfig)
        {
            base.OnConfigurationChanged(newConfig);

            Element page = Element.RootPage;
            MasterDetailPage masterDetailPage = null;
            System.Diagnostics.Debug.WriteLine("page: " + (page == null).ToString());
             masterDetailPage = page as MasterDetailPage;

            System.Diagnostics.Debug.WriteLine("masterDetailPage: " + (masterDetailPage == null).ToString());
            if (masterDetailPage == null)
                return;

            var renderer = Platform.GetRenderer(masterDetailPage) as MasterDetailPageRenderer;
            System.Diagnostics.Debug.WriteLine("renderer: " + (renderer == null).ToString());
            if (renderer == null)
                return;

            var drawerLayout = (DrawerLayout)renderer;
            Toolbar toolbar = null;
            System.Diagnostics.Debug.WriteLine("ChildCount: " + ChildCount);
            for (int i = 0; i < ChildCount; i++)
            {
                var child = GetChildAt(i);
                toolbar = child as Toolbar;
                System.Diagnostics.Debug.WriteLine("ID:" + toolbar?.Id);
            }
            System.Diagnostics.Debug.WriteLine("toolbar: " + (toolbar == null).ToString());

            toolbar.SetNavigationOnClickListener(new MenuClickListener(Element, drawerLayout));
        }

        protected override void OnAttachedToWindow()
        {
            base.OnAttachedToWindow();

            Element page = Element.RootPage;
            MasterDetailPage masterDetailPage = null;
            System.Diagnostics.Debug.WriteLine("page: " + (page == null).ToString());
            masterDetailPage = page as MasterDetailPage;

            System.Diagnostics.Debug.WriteLine("masterDetailPage: " + (masterDetailPage == null).ToString());
            if (masterDetailPage == null)
                return;

            var renderer = Platform.GetRenderer(masterDetailPage) as MasterDetailPageRenderer;
            System.Diagnostics.Debug.WriteLine("renderer: " + (renderer == null).ToString());
            if (renderer == null)
                return;

            var drawerLayout = (DrawerLayout)renderer;
            Toolbar toolbar = null;
            System.Diagnostics.Debug.WriteLine("ChildCount: " + ChildCount);
            for (int i = 0; i < ChildCount; i++)
            {
                var child = GetChildAt(i);
                toolbar = child as Toolbar;
                System.Diagnostics.Debug.WriteLine("ID:" + toolbar?.Id);
                if (toolbar != null)
                    break;
            }
            System.Diagnostics.Debug.WriteLine("toolbar: " + (toolbar == null).ToString());

            toolbar.SetNavigationOnClickListener(new MenuClickListener(Element, drawerLayout));
        }

        private class MenuClickListener : Java.Lang.Object, IOnClickListener
        {
            readonly NavigationPage navigationPage;
            private DrawerLayout layout;

            public MenuClickListener(NavigationPage navigationPage, DrawerLayout layout)
            {
                System.Diagnostics.Debug.WriteLine("page: Listening");
                this.navigationPage = navigationPage;
                this.layout = layout;
            }

            public void OnClick(Android.Views.View v)
            {
                System.Diagnostics.Debug.WriteLine("page: Clicked");
                var page = navigationPage.CurrentPage as VContentPage;
                var master = navigationPage.CurrentPage as MasterDetailHomePage;
                if (navigationPage.Navigation.NavigationStack.Count <= 1)
                {
                    layout.OpenDrawer((int)GravityFlags.Left);
                }

                if (page != null)
                {
                    if (page.CustomBackButtonAction == null)
                    {
                        navigationPage?.PopAsync();
                    }
                    else
                    {
                        page.CustomBackButtonAction.Invoke();
                    }
                }
                else if (master != null)
                {
                    master.RetractMaster();
                }
                else
                {
                    navigationPage?.PopAsync();
                }
            }
        }
    }
}

Answer 1

您的点击事件可能无法正常运行的原因是，在对配置进行更改时调用了onConfigurationChanged之后，您并未将这些值重新分配给对象。

尝试这样的事情：

 protected override void OnConfigurationChanged(Configuration newConfig)
    {
        base.OnConfigurationChanged(newConfig);
       if(newConfig.Orientation==Orientation.Landscape)
           //Code for landscape mode
        else if(newConfig.Orientation==Orientation.Portrait)
           //Code for potrait mode
    }

触发OnConfigurationChanged时不会触发OnClick事件

1 个答案: