Problem Statement
How does StreamBuilder differ from FutureBuilder?
Explanation
StreamBuilder listens to a Stream and rebuilds every time the stream emits a new value, perfect for continuously updating data like real-time chat messages, live counters, or Firestore snapshots. It works similarly to FutureBuilder but handles multiple values over time rather than just one. StreamBuilder automatically manages stream subscription and disposal when the widget is removed.
The builder function receives AsyncSnapshot just like FutureBuilder, but it's called every time the stream emits. Check snapshot.hasData to display data, snapshot.hasError for errors, and snapshot.connectionState for waiting states. StreamBuilder is reactive - your UI automatically updates as new data arrives from the stream without manual state management.
Use StreamBuilder for real-time data sources that emit continuously like Firestore queries with onSnapshot, WebSocket connections, timer ticks, or any continuous data source. Use FutureBuilder for one-time async operations. StreamBuilder properly handles subscription cleanup preventing memory leaks, making it the standard way to consume streams in Flutter UI.
