Final answer:
On a small screen, an activity usually shows one fragment, called a single-pane layout, which is a common pattern in Android app development for optimizing user experience across various device screen sizes.
Step-by-step explanation:
On a small screen, an activity typically only displays a single fragment. This is known as a single-pane layout. In the context of mobile app development, especially on Android platforms, a single-pane layout is a design pattern where one fragment is shown at a time.
When developers are designing for devices with larger screens, like tablets, they may opt for a multi-pane layout where multiple fragments are displayed side-by-side.
Understanding how to design and implement these layouts is crucial for creating a good user experience on devices with different screen sizes.
On a small screen, an activity typically only displays a single fragment. This is known as a single-pane UI.