Android-PWA-Wrapper

A sample Android Wrapper application to create a native Android App from an offline-capable Progressive Web App.

Drafted for the Android App of my Leasing Calculator Web App using React, Redux, Materialize.css and a lot of Offline-First love over at leasingrechnen.at.

Why would I use a wrapper?

I know, using a Wrapper-App to display a Website can feel a bit odd. But there are a few good reasons why you'd package your Web App like this.

If you've got a very sophisticated UI already, it might make sense not to rebuild it from scratch for multiple platforms, especally if it's a Single Page Application already, that doesn't "feel" like a Website.
There might be as well less competition for a given niche on App Stores, in comparison to Google directly. With leasingrechnen.at, I've got easily into the Top 10 Apps on Google Play for my country, whereas Google Search put me on page 9 as the Site is relatively new.

Sets up a WebView just the way PWAs/SPAs like it (e.g. enables App cache and DOM storage, ...).
Shows a loading spinner while fetching the Web App.
Provided your Web App is Offline-capable, it only needs an Internet connection on the first startup. If this fails, it shows a native refresh widget.
Opens all external URLs in the device's Browser instead.
Checks for Internet connection and fetches Updates for your Web App accordingly.
Is compatible down to JellyBean, although it's recommended to build for SDK Version >= 19 (KitKat). Building for SDK Version >= 21 (Lollipop) puts you on the safe side without having to worry too much about Browser support.
APK-size < 1.4 MB. The latest cat video from WhatsApp weighs heavier ;)

Clone/fork repository
Put your Web App's URL in WEBAPP_URL in Constants.java
Replace app_name in strings.xml with the name of your App
Add your own primary colors to colors.xml (colorPrimary, colorPrimaryDark, colorPrimaryLight)
Put your own icons in place:
- Add your own ic_launcher.png and ic_launcher_round.png in the mipmap folders
- Add your own ic_appbar.png in the drawables folders. This is displayed in Android's Recent Apps View on your app bar, so it should look nicely when placed on top of your primary color.
- I recommend using Android Asset Studio to get the icons ready in no time
Change the package name in app/build.gradle, applicationId
Change AndroidManifest.xml -> aplication -> activity -> intent-filter to your own URLs/schemes/patterns/etc. or remove the intent-filter for android.intent.action.VIEW altogether
Check Constants.java for more options
Build App in Android Studio

GNU General Public License v3.0 - if you use it, we wanna see it!