How to change the text on a button progamatically?

Use your view's object to initialize

`Button mButton = (Button)your_view_object.findViewById(R.id.contact);
mButton.setText("number");`

For example, consider you have inflated a view like this:

`View View = mInflater.inflate(R.layout.gridelement, null);`

Also if you wish to learn more about CSS, refer to this CSS hub https://www.scaler.com/topics/css/