Daily Archives: Friday, September 15, 2017

Cordova, Ionic, iOS, Phonegap

Using Ionic’s WKWebView Engine with standard cordova/phonegap projects

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The guys at ionic have created a branch of phonegap’s WKWebView Engine (for iOS) with a number of improvements such as local AJAX request ability. This is great for ionic projects, however I wanted to see if it could be used in a standard phonegap project for which the standard WKWebView plugin wouldn’t work.

For those who don’t know, older versions of iOS had an implementation of webview which was called UIWebView. This had a number of bugs and performance issues, however because cordova/phonegap strive to maintain backwards-compatibility, it is still the default within phonegap projects. WKWebView is faster, more stable and has newer features such as IndexedDB, however it has some additional security restrictions (especially with CORS and local file loading) meaning it is not simply a drop-in replacement for UIWebView.

Installation is simple, more details can be found on the github project page, however basically just run:

cordova plugin add https://github.com/ionic-team/cordova-plugin-wkwebview-engine.git --save

and it will be included in your iOS project. Make sure that your app works (and detects it’s being run from within cordova) when the window.location is set to 'http://localhost:8080/' rather than the usual file:// path. Then, add the necessary configuration into config.xml:

<platform name="ios">
    <access origin="http://localhost:8080/*" />
    <allow-navigation href="http://localhost:8080/*" />
    <feature name="CDVWKWebViewEngine">
        <param name="ios-package" value="CDVWKWebViewEngine" />
    </feature>
    <preference name="CordovaWebViewEngine" value="CDVWKWebViewEngine" />
</platform>

However, even if you do this, when you open the test app you’ll find that you are for some strange reason unable to scroll! This is because the ionic framework doesn’t use body scrolling, it has subelements with overflow: auto set on them. However for most non-ionic apps you probably want body scrolling. Simply change add the following into the ios platform configuration section in config.xml:

    <preference name="ScrollEnabled" value="true" />

If you are accessing remote API services, you’ll also need to modify some CORS settings on your server. In my post tomorrow I’ll show you how to do this easily without increasing the load on your API service.