Fillparent

Fillparent, also known as match_parent in Android development, is a layout parameter or value used in user interface design, particularly within frameworks like Android's XML layouts. Its primary function is to instruct a view or widget to expand and occupy all the remaining space available within its parent container. This expansion is relative to the parent's dimensions, meaning if the parent is wider, the child will be wider; if the parent is taller, the child will be taller.

When a view is set to fillparent, it will dynamically adjust its size based on the available space. This is distinct from other layout values like wrap_content, which makes a view size itself just enough to contain its content, or fixed dimensions, which set a specific width and height. Fillparent is useful for creating responsive layouts that adapt to different screen sizes and orientations. For instance, a list item or a button might be set to fillparent horizontally to ensure it spans the entire width of the screen, regardless of how it's held.

The behavior of fillparent can be influenced by other layout constraints or properties within the parent container. For example, if the parent has multiple children all set to fillparent, they might divide the available space equally or based on other specified weights. Understanding fillparent is crucial for developers aiming to create flexible and visually consistent user interfaces across a range of devices.