change a value in xamarin forms through a website

Question

Hi every one. I'm kind of new to Xamarin and I have a simple problem but no idea to how do that.

I have written an app with Xamarin forms. the problem is Here that I want user connect to my website do sth and then come back to the app. I need to change a Boolean in Xamarin to true when
the task is done in website.

how I can get this information (just turn a false to true) from web?
I have no idea so any help will appreciated.

Answer 1

Hello,​

Welcome to our Microsoft Q&A platform!

I make a test with a button click then send a value(true) to the C# code in HTML, running result like following screenshot.

To achieve it, you can use Js calls methods in C#.

Create a Custom renderer for your webview (note HybridWebView is extend of webview in xamarin forms.), then AddJavascriptInterface called CSharp

   [assembly: ExportRenderer(typeof(HybridWebView), typeof(HybridWebViewRenderer))]  
   namespace WebviewInvokeJS.Droid  
   {  
     
       public class HybridWebViewRenderer : WebViewRenderer  
       {  
           Context _context;  
           public HybridWebViewRenderer(Context context) : base(context)  
           {  
               _context = context;  
           }  
           protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)  
           {  
     
               if (Control != null)  
               {  
                   Control.Settings.JavaScriptEnabled = true;  
                   Control.AddJavascriptInterface(new HybridJSBridge(Android.App.Application.Context), "CSharp");  
                   Control.SetWebViewClient(new WebViewClient());  
     
                    
                   Control.LoadUrl("file:///android_asset/index1.html");  
                    
               }  
               base.OnElementPropertyChanged(sender, e);  
           }  
       }  
   }  

Then create a class called HybridJSBridge.cs.

   using System.Linq;  
   using System.Text;  
     
   using Android.App;  
   using Android.Content;  
   using Android.OS;  
   using Android.Runtime;  
   using Android.Views;  
   using Android.Webkit;  
   using Android.Widget;  
   using Java.Interop;  
     
   namespace WebviewInvokeJS.Droid  
   {  
       public class HybridJSBridge : Java.Lang.Object  
       {  
           Context context;  
     
           public HybridJSBridge(Context context)  
           {  
               this.context = context;  
           }  
     
           [JavascriptInterface]  
           [Export]  
           public void ShowToast(string msg)  
           {  
               Toast.MakeText(context, msg, ToastLength.Short).Show();  
           }  
     
       }  
   }  

My html code is like following screenshot(this site cannot post html code). If you task is finished, you can call this CSharp.ShowToast (true) JS to return a value.

For more details, you can refer to this thread as well.

Best Regards,

Leon Lu

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