I solved it in a rather unorthodox way, something I probably wouldn't recommend ANYONE but I'll write it anyway since maybe it will help someone who's in a hurry to get it done. Just remember this is a bad way of doing it.
My app basically consists of 4 buttons and a browserfield.
To display a spinning "load animation" I use alishaik786's tip (see his comments) of the custom PopupScreen triggered by a browserfieldlistener:
// BrowserFieldListener to catch when a page started loading and when it is finished
BrowserFieldListener listener = new BrowserFieldListener() {
public void documentCreated(BrowserField browserField, ScriptEngine scriptEngine, Document document) throws Exception{
displayLoadAnimation();
// see method below
}
public void documentLoaded(BrowserField browserField, Document document) throws Exception{
try{
popUp.close();
}catch(IllegalStateException es){
es.printStackTrace();
}
}
};
// The method for showing the popup
private void displayLoadAnimation(){
popUp = new LoadingPopupScreen();
UiApplication.getUiApplication().invokeLater(new Runnable() {
public void run() {
UiApplication.getUiApplication().pushScreen(popUp);
}
});
}
Then in my custom PopupScreen I check where the user is clicking in "protected boolean touchEvent(TouchEvent event)" by checking event.getGlobalY() & event.getGlobalX() of the touch and comparing it to the positions of the buttons. If the user presses within the X&Y of a button then the popup screen is closed and I trigger the button being pressed.
As I said this is a bad way of doing it (many things need to be static), but it works if you want a quick and dirty sollution.