title: Android WebView custom headers
body: <p>I am currently using this code to add a custom header to android <code>WebView</code></p>
  
  <pre><code>Map&lt;String, String&gt; extraHeaders = new HashMap&lt;String, String&gt;();
  extraHeaders.put("example", "header");
  webView.loadUrl(url, extraHeader);
  </code></pre>
  
  <p>Above code is working but only on the main page. So if I write this code <code>echo $_SERVER['example']</code> it prints <code>header</code>. But there is an <code>iframe</code> in the loaded URL which shows an undefined error when I try the same code. Is there any way I can fix this? </p>
  
  <p>So what I want to do is add custom header not only to the main loaded URL but also on the <code>iframe</code> of the loaded page.</p>