ngAndroid is bringing angularjs type directives to android xml attributes.
It is a standard TextView subclass driven by RxJava Observable.interval towards defined numerical target, which you can specify either by standard setTarget(long target) or you can tie it to your Rx stream via public Action1<Long> targetAction() (RxJava1) or Consumer<Long> targetConsumer() (RxJava2) respectively.
Image zoomer provides easy way to add zoom animations to you ImageButton. You can set the animation duration and reverse mode to reverse the animation.