Hof.js android

Hof.js android is a modern library for the development of Hof.js based Android apps and is a part of the Hof.js project. It is an open source project of Hof University of Applied Sciences and was created by Prof. Dr. Walter Kern.

Hof.js android provides an Activity base class that renders any Hof.js-based application deployed to the app assets folder. Additionally, helper classes for common use cases are provided.

Contact us if you are a student of Hof University of Applied Sciences and would like to contribute.

Contact

• Organization: https://www.hof-university.de
• Mail: hofjs@hof-university.de
• Impressum / Imprint: https://www.hof-university.de/impressum.html

Key features

This framework has the following advantages, among others:

• Extremely simple packaging of Hof.js apps, because you can simply copy the Hof.js app folder to the app assets folder.
• Good render performance because using modern Android apis to call local resources means no local web server is needed, so the corresponding overhead is eliminated.
• Fetch API accesses to any web page work, giving hosted Hof.js apps the same capabilities as native Android apps, and without plugins or special APIs on the client..
• Useful helper libraries support periodic updates of app content.

Introductory examples

Simple loading of a Hof.js app

The following sample shows the minimal code required to render a Hof.js app as Android app.

package de.sample.hofjsapp

import android.os.Bundle

class MainActivity : PwaActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        // All that is required to load startpage of hof.js app
        // (file has to be placed in src/main/assets)
        setContentUrl("index.html") 
    }
}

Loading of a Hof.js app and exposing functions to Hof.js app javascript code

The following sample shows a feature to support Android activity functions to be called from the JavaScript code of the provided Hof.js app.

package de.sample.hofjsapp

import android.os.Bundle

class MainActivity : PwaActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        // All that is required to load startpage of hof.js app
        // (file has to be placed in src/main/assets)
        setContentUrl("index.html", "pwaActivity") 
    }

    @JavascriptInterface
    fun sayHello(name: String) {
        // This method can be called from JavaScript of Hof.js app
        // by using pwaActivity.sayHello("World")
    }
}

Documentation

Currently there is no special documentation, because the usage as shown in the example above is very simple.

You can contribute by sending pull requests to this repository.

License

Hof.js android is MIT licensed.