Accessing Activity Methods from WebChromeClient

Question

I am using Xamarin to write an Android application, and in that application, I have a webview that needs to load at the creation of the app and after it is fully loaded, I call some javascript into the HTML page to set up the graph.

I am trying to use a custom WebChromeClient to override the OnProgressChanged method, where when it fully loads, it calls a method in my MainActivity.

Here is the MainActivity code:

using System;
using System.Text;
using System.Timers;
using System.Collections;
using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
using Android.Text;
using Android.Text.Style;
using Android.Webkit;

public class MainActivity : Activity
{
     WebView graph;

     protected override void OnCreate (Bundle bundle)
     {
          base.OnCreate (bundle);
          SetContentView (Resource.Layout.Main);

          graph = FindViewById<WebView>(Resource.Id.webGraph);

          //Initializes the WebView
          graph.SetWebChromeClient(new myWebChromeClient()); 
          graph.Settings.JavaScriptEnabled = true;
          graph.LoadUrl("file:///android_asset/graph.html");

And the myWebChromeClient class I created looks like this:

class myWebChromeClient : WebChromeClient
{
     public override void OnProgressChanged(WebView view, int newProgress)
     {
          base.OnProgressChanged(view, newProgress);

          if (newProgress == 100) {MainActivity.setUpGraph();}
     }
}

The myWebChromeClient is within the MainActivity, but I am unable to access the setUpGraph method even though it is a public method.

Any help will be appreciated!

Answer 1

Accept and store a reference of type MainActivity in myWebChromeClient class. Only then can you call the setUpGraph() function in MainActivity.

EDIT

The myWebChromeClient class:

class myWebChromeClient : WebChromeClient
{
     public MainActivity activity;
     public override void OnProgressChanged(WebView view, int newProgress)
     {
          base.OnProgressChanged(view, newProgress);

          if (newProgress == 100) { activity.setUpGraph(); }
     }
}

And the activity:

    public class MainActivity : Activity
    {
         WebView graph;

         protected override void OnCreate (Bundle bundle)
         {
              base.OnCreate (bundle);
          SetContentView (Resource.Layout.Main);

          graph = FindViewById<WebView>(Resource.Id.webGraph);

          //Initializes the WebView
          myWebChromeClient client = new myWebChromeClient(); 
          client.activity = this;
          graph.SetWebChromeClient(client); 
          graph.Settings.JavaScriptEnabled = true;
          graph.LoadUrl("file:///android_asset/graph.html");

For the sake of simplicity, I've added a public variable to the client, please don't use the same in production. Pass the reference in a constructor or use get-set.