I already know that if you have n elements with equal heights=fill_parent, they get the same size so they fill the parent among all of them.
But I would like to have, for example a component 1/4 of the screen height, and another component 3/4. How can that be done?
You should use a linear layout to do this
Use layout_weight to manipulate the ratio of fill.
You can also have the values as 1.0 and 3.0 respectively, just so long as the ratio is correct.