I am trying to achieve the morphing effect, when the user clicks myButton, the image inside the ImageView should morph from arrow to checkmark. And when he clicks it again, the
I will go with Circular Progress Button, you can customize it based on your need or extend the library (since. it's open source). I have been using that for a while and it is pretty easy to integrate on your projects.
Also, you can learn from that and create your own library :-)
Here the Git repository CircularProgressButton
Also, you can try out other excellent open source such as Android Morphing Button