title: What's a state in flutter?
body: <p>I just started learning Flutter and as a beginner I'm facing some issues about understanding a state. I watched some videos on YouTube, read articles online. They explain the reason why one should use a Stateful Widget instead of Stateless. But I can't really understand what part of an app needs to be a Stateful Widget and what the use of the setState method is. Also what's the difference between the state of a widget and state of the app?</p>