Question: I currently use this

```
mywebview.setUrl(the_url);

```

to load a URL. 

Can I, instead, load it in such as way as to include a referer in the http header? 

EDIT: The reason for this is that the linked-to website should be able to see where the traffic is coming from even if the URL is loaded into a different webview than the one that contained the link. (I use multiple WebViews to create a tab UI.)

Edit:
The xcode equivalent seems to be this, although I'm not sure if this is also loading it into a new webview: [Specifying HTTP referer in embedded UIWebView](https://stackoverflow.com/questions/7913305/specifying-http-referer-in-embedded-uiwebview)

Answer: 
It appears defining custom headers for WebViews is not available yet. You can watch ticket [TIMOB-17467](https://jira.appcelerator.org/browse/TIMOB-17467) to view updates.

It appears you will need a native module. 

A quick check for iOS.. 

* [Safari Dialog module](https://github.com/appcelerator-modules/Ti.SafariDialog/blob/master/apidoc/SafariDialog.yml) doesn't support headers (class limitation).
* [WKWebview module](https://github.com/kaga/Titanium-Module-WKWebview) doesn't support headers (appears to be possible).

Perhaps you could extend these.

Android appears to be easier to implement, (but still not available in Titanium SDK), via `extraHeaders`: Read more: <https://stackoverflow.com/a/5342527>
I've looked at the Android Webview header (php `getallheaders()`) and there is `x-requested-with: com.app.id` 

So in you page you could check for that value and know at least that it was visited by the app with the bundle identifier. Otherwise you could attach a get parameter to the url `?mobile` and count this.

I'm trying to add a patch to the Android SDK and add a setHeader() method. The loadUrl() call is at:
<https://github.com/appcelerator/titanium_mobile/blob/bc85170157d3bebc5de1d61a9fe6e34bce84a8c9/android/modules/ui/src/java/ti/modules/titanium/ui/widget/webview/TiUIWebView.java#L462>

If you change it according to @tzmartin 

```
extraHeaders.put("Referer", "http://www.referer.tld/login.html");
getWebView().loadUrl(finalUrl, extraHeaders);

```

then it already works but its hard coded.