How to inject JavaScript to WebView whenever required?

Question

This link shows how to inject JavaScript code to WebView object in Android. However it's available only once, via onPageFinished(webView,url), when the page is finished loading.

Is there a way (how ?) to keep that "injection" ability "forever", whenever necessary ?

Answer 1

I use :

  mWebView.loadUrl("javascript:alert('hello')");