Passing Data From Javascript To Android WebView

Question

I have written a piece of Java code which is intended as to call Java code from Javascript by a android WebView gateway.

webView = (WebView) findViewById(R.id.captchaView);
WebSettings ws = webView.getSettings();
ws.setJavaScriptEnabled(true);
webView.loadUrl("https://google.com/");

webView.setWebViewClient(BrowserHandler);
webView.addJavascriptInterface(new IJavascriptHandler(), "cpjs");

WebViewClient BrowserHandler = new WebViewClient() {
   @Override
   public void onPageFinished(WebView view, String url) {
      view.loadUrl("javascript:window.cpjs.onPageLoaded(document.body.innerHTML);void(0);");
   }
};

final class IJavascriptHandler {
   IJavascriptHandler() {
   }

   public void onPageLoaded(String html) {
      // this is called from JS
      Toast t = Toast.makeText(getApplicationContext(), "Yes", 2000);
      t.show();
   }
}

The above code checks for web page load and once the page is finished loading, it will call javascript function which is exposed from Java so it could carry what I need from the page.

This is not working as expected what it does is simply refresh the page every few seconds. I am not sure what is wrong here?

will you please send me the updated code. thanks in advance

Harshil Kulkarni
– Harshil Kulkarni

2017-02-22 04:14:10 +00:00
Commented Feb 22, 2017 at 4:14 — Harshil Kulkarni
– Harshil Kulkarni, Commented Feb 22, 2017 at 4:14

CommonsWare · Accepted Answer · 2011-02-05 12:46:51Z

2

Well, there are lots of things that are rather strange in what you have done.

From Java, you are triggering Javascript...to call back into Java. You are assuming this is safe.
You are loading the Google home page, which will perform a redirect when it encounters an Android browser, the last time I checked.
You are attempting to display a Toast, yet you have no idea if that code will run on the main application thread or not.

answered Feb 5, 2011 at 12:46

CommonsWare

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1 Comment

Umair A. Over a year ago

You are right. Toast will be run on UI thread. I just got to know it's a bug in WebView which is why this is not working. I have a thread on Google Groups for Android also I need to can I uninstall emulator from version 2.3 back to 2.2?

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