如何從Xamarin droid Assist活動重置Xamarin表單導航堆棧

Question

Helo，我正在為我的應用程序添加輔助功能，當用戶按下主頁按鈕時，會打開一個帶有卡片的android活動，用戶可以單擊該卡片，然后打開有問題的xamarin表單頁面，例如當數學卡片是單擊MathPage xamarin表單頁面會打開此功能，但如果我在后台運行xamarin表單應用程序，則無論單擊什么按鈕，它都會加載主屏幕布局。 如果我關閉了多任務處理的xamarin表單應用程序，並按住主頁按鈕並單擊數學卡，它將打開MathPage。

這是我的android活動代碼：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using Android.App;
using Android.Content;
using Android.Content.PM;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Xamarin.Forms.Platform.Android;

namespace Appname.Droid
{
[Activity(LaunchMode = LaunchMode.SingleInstance, Theme = "@style/Theme.Transparent")]
    [IntentFilter(new[] { Intent.ActionAssist }, Categories = new[] { Intent.CategoryDefault })]    
    public class ToolBelt : Activity
    {


        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.ToolBelt);

        }


        //Code That Opens The Math Part!

        [Java.Interop.Export("math")] // The value found in android:onClick attribute.
        public void btnOneClick4(View v) // Does not need to match value in above attribute.
        {

            var intent = new Intent(ApplicationContext, typeof(MainActivity));
            intent.PutExtra("page", "Math");
            StartActivity(intent);
        }


        //Code That Opens The Science Part!

        [Java.Interop.Export("science")] // The value found in android:onClick attribute.
        public void btnOneClick9(View v) // Does not need to match value in above attribute.
        {

            var intent = new Intent(ApplicationContext, typeof(MainActivity));
            intent.PutExtra("page", "Science");
            StartActivity(intent);
        }



        //Code That Opens The Handwriting  Part!

        [Java.Interop.Export("english")] // The value found in android:onClick attribute.
        public void btnOneClick10(View v) // Does not need to match value in above attribute.
        {

            var intent = new Intent(ApplicationContext, typeof(MainActivity));
            intent.PutExtra("page", "Handwriten");
            StartActivity(intent);
        }



        //Code That Opens The Flascards  Part!

        [Java.Interop.Export("flashcard")] // The value found in android:onClick attribute.
        public void btnOneClick11(View v) // Does not need to match value in above attribute.
        {

            var intent = new Intent(ApplicationContext, typeof(MainActivity));
            intent.PutExtra("page", "Flashcards");
            StartActivity(intent);
        }

        //Code That Opens The Internet  App!

        [Java.Interop.Export("web")] // The value found in android:onClick attribute.
        public void btnOneClick8(View v) // Does not need to match value in above attribute.
        {
            var uri = Android.Net.Uri.Parse("http://www.google.com");
            var intent = new Intent(Intent.ActionView, uri);
            StartActivity(intent);
        }



        //Code That Opens The Gmail App!

        [Java.Interop.Export("email")] // The value found in android:onClick attribute.
        public void btnOneClick3(View v) // Does not need to match value in above attribute.
        {
            var intent = PackageManager.GetLaunchIntentForPackage("com.google.android.gm");
            StartActivity(intent);
        }



        //Code That Opens The Books App!

        [Java.Interop.Export("books")] // The value found in android:onClick attribute.
        public void btnOneClick5(View v) // Does not need to match value in above attribute.
        {
            var intent = PackageManager.GetLaunchIntentForPackage("com.google.android.apps.books");
            StartActivity(intent);
        }

    }
}

這是MainActivity機器人代碼：

using System;

using Android.App;
using Android.Content;
using Android.Content.PM;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
using System.Collections.Generic;
using AppName.Droid;
using AppName.Data;

[assembly: Xamarin.Forms.Dependency(typeof(MainActivity))]
namespace AppName.Droid
{
    [Activity(Label = "AppName", Icon = "@drawable/ic_launcher", Theme = "@style/MyTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]
    public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity, SchoolTools.PackageInterface
    {
    protected override void OnCreate(Bundle savedInstanceState)
        {
            TabLayoutResource = Resource.Layout.Tabbar;
            ToolbarResource = Resource.Layout.Toolbar;

        base.OnCreate(savedInstanceState);

        global::Xamarin.Forms.Forms.Init(this, savedInstanceState);
            var page = Intent.GetStringExtra("page");
            LoadApplication(new App(page));


        }

        public IList<Apps> GetInstalledApps()
        {
            IList<Apps> apps = new List<Apps>();
            var pkgInfos = global::Xamarin.Forms.Forms.Context.PackageManager.GetInstalledPackages(PackageInfoFlags.Activities);
            foreach(var pi in pkgInfos)
            {
                // skip system packages
                if (pi.ApplicationInfo.DataDir.StartsWith("/data/user/"))
                {
                    Apps app = new Apps(pi.ApplicationInfo.LoadLabel(global::Xamarin.Forms.Forms.Context.PackageManager).ToString(), pi.PackageName);
                    if (!apps.Contains(app))
                    {
                        apps.Add(app);
                    }
                }
            }
            return apps;
        }

        public bool Launch(string package)
        {
            var intent = Application.Context.PackageManager.GetLaunchIntentForPackage(package);
            bool retVal = IsIntentAvailable(intent);
            if (retVal)
            {
                intent.AddFlags(ActivityFlags.NewTask);
                Application.Context.StartActivity(intent);
            }
            return retVal;
        }

        private static bool IsIntentAvailable(Intent intent)
        {
            return intent != null && Application.Context.PackageManager.QueryIntentActivities(intent, 0).Count != 0;
        }
    }
}

這是我的app.cs代碼：

using System;

using Xamarin.Forms;

namespace AppName
{
    public class App : Application
    {

        public App(string pageName = "AppNameHome")
        {
            switch (pageName)
            {
                case "Math":

                    MainPage = new NavigationPage(new MathPage());

                    break;


                    case "Science":
                    MainPage = new NavigationPage(new Science.ScienceToolsPage());
                    break;

                        case "Handwriten":
                    MainPage = new NavigationPage(new Handwriting.HandwritingToolsPage());
                    break;

                            case "Flashcards":
                    MainPage = new NavigationPage(new Flashcards.FlashCardHome());
                    break;

                    default:
                    MainPage = new NavigationPage(new AppNameHome());

                    break;


            }



        }

        protected override void OnStart()
        {
            // Handle when your app starts
        }

        protected override void OnSleep()
        {
            // Handle when your app sleeps
        }

        protected override void OnResume()
        {
            // Handle when your app resumes
        }
    }
}

任何幫助都將是驚人的！

提前致謝 ：）

Answer 1

我發現我也需要將SingleInstance添加到主要活動中的問題是nohistory = true，這是解決此問題所需的代碼：

[Activity(LaunchMode = LaunchMode.SingleInstance, NoHistory = true,
 Label = "AppName", Icon = "@drawable/ic_launcher", Theme = "@style/MyTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]