title: Track page navigation of PDF being displayed in WebView of android?
body: <p>I'm displaying PDF in webview using google docs. Is there any way to know when user moves to next page?</p>
  
  <p>My requirement is that I have an agreement begin displayed in PDF format through <code>WebView</code>, now when user moves to next page a <code>CheckBox</code> should appear, so I want to track page change.</p>
  
  <p>Description of my scenario:</p>
  
  <p>In image below, a PDF of ten pages is being displayed using <code>WebView</code>, now when user turns to next page using arrows present on right top, I need to know the change of event.</p>
  
  <p><img src="https://i.stack.imgur.com/FNGap.png" alt="enter image description here"> </p>
  
  <p>I tried to use <code>onProgressChanged()</code>, but it didn't help.</p>
  
  <pre><code>webView.setWebChromeClient(new WebChromeClient() {
             public void onProgressChanged(WebView view, int progress) {
               // Activities and WebViews measure progress with different scales.
               // The progress meter will automatically disappear when we reach 100%
                 Toast toast = Toast.makeText(getApplicationContext(), "PAge change detected", Toast.LENGTH_LONG);
                  toast.setGravity(Gravity.CENTER, 0, 0);
                  toast.show();
             }
           });
  </code></pre>
  
  <p>I also tried using <code>onLoadResource()</code>,<code>shouldInterceptRequest()</code>, both of them didn't work.</p>