Layout managers are software components used in widget toolkits which have the ability to lay out graphical control elements by their relative positions without using distance units.
It is often more natural to define component layouts in this manner than to define their position in pixels or common distance units, so a number of popular widget toolkits include this ability by default.
Widget toolkits that provide this function can generally be classified into two groups: Android have the ConstraintLayout.
This piece of code shows 3 buttons stacked on top of each other in a vertical box.
The FlowLayout layout manager arranges components in a directional flow, much like lines of text in a paragraph.