What is FutureBuilder?
vThe FutureBuilder method is the backbone of every JSON flutter mobile application. Using the FutureBuilder method we can use 2 separate conditions from which we can manage Displaying loading indicators or other widgets before parsing JSON in other widgets. But as we all know if you are a beginner in Flutter then you all have faced a problem regarding FutureBuilder. FutureBuilder by default calls multiple times in the Stateful widget and how we can control it So Futures have one and only one response. A common usage Future is to handle HTTP calls
What is StreamBuilder?
vThe StreamBuilderwidget is used in many kinds of Flutter applications, especially chat applications, social networks, real-time content updates, etc. a widget that builds itself based on the latest snapshot of interaction with a stream.
What is the Difference?
vStreamBuilder and FutureBuilder have the same behavior and they listen to changes on their respective object (Future and Stream). But their difference comes with how they listen to async calls.
vWhen we use FutureBuilder, it has only one response. Because it uses the Future object and Future has one and only one response. Future is used to handle HTTP requests. So we listen to a Future is its state. When it’s done or had an error, that’s it.
vWhen we use StreamBuilder, it uses stream object, and stream like a pipe, when you put a value on the one end and if there is a listener on the other hand it will receive the value that you put. It usually is the representation of web-sockets or events (such as click). By listening to a Stream you'll get each new value and also if the Stream had an error or completed.
vSo in the end, their differences are how the object they listen to works.
vBoth StreamBuilder and FutureBuilder have the same behavior: They listen to changes on their respective object. And trigger a new build when they are notified of a new value.
vIf you need to build a widget based on the result of a Stream, you can use the StreamBuilder widget. You can create a Stream and pass it as the stream argument. Then, you have to pass an AsyncWidgetBuilder function which is used to build a widget based on the snapshots of the Stream.