You can have a look at Gluon Charm
Down library, an open source module for accessing seamlessly the low level platform APIs.
The current version is 0.0.2-SNAPSHOT, so you need to include the maven url on your build.gradle file, along with the different dependencies:
repositories {
jcenter()
maven {
}
}
dependencies {
compile "com.gluonhq:charm-down-common:0.0.2-SNAPSHOT"
desktopRuntime "com.gluonhq:charm-down-desktop:0.0.2-SNAPSHOT"
androidRuntime "com.gluonhq:charm-down-android:0.0.2-SNAPSHOT"
iosRuntime "com.gluonhq:charm-down-ios:0.0.2-SNAPSHOT"
}
Now on your project, you can use launchExternalBrowser(String url). It will work on desktop, iOS and Android.
If you are interested in how this is implemented, have a look at the source code
here.
Jose