UI Software and Technology

UI Software and Technology

1. State Machine

   • Consists of states
   • Consists of inputs
     • Inputs in a state machine allow for movement to specific states
   • Moving from state to state is a "transition"

2. Buttons from modern OS systems are more complicated than simple state machines

   • Have an inactive state

3. Model, View, Controller

   • Division of responsibilities within code
   • Model: stores and retrieves data
   • View: present data and listen for user input
   • Controller: manages interactions between data storage and presentation by using a state machine

4. View Hierarchies

   • UI's are structured as hierarchies
   • Containers can give widgets a layout
     • Containers are tree components that aren't visible in the UI
   • Event propagation is a process where UI events move from a physical device to UI component
     • Examples of devices are mice, keyboards, speech, etc.