Button bar Menu
1 – In Designer, drag an element called HorizontalArrangement. It allows you to organize elements inside a horizontal structure in the screen.
2 – Under its properties, change the width to Fill parent, which means it will fill all the superior element in the hierarchy.
3 – Now insert more X HorizontalArrangement elements inside the original, where X = number of buttons you intend to insert. Take care for not putting one inside the other, but all parallel, inside the initial. The Components section will help you with that.
4 – Access each element in the internal HorizontalArrangements and change its width to Fill parent.
5 – Now, insert a Button element inside each internal HorizontalArrangement.
6 – By its turn, under the Properties of each button, edit width so it’s Fill parent as well.
7 – Now, they’re all alligned. Don’t forget a) to access Blocks to build the link for each button; and b) that in each screen to where the button directs, this menu should persist, which means that you should replicate it on the other screens.