Widget

• Widgets are the building blocks. Similar to components in react.js
• UI as Code: build a widget tree with a combination of nested widgets
• Material Design
• It's the Design System create and heavily used by Google
• Material Design is built into Flutter (but you can also change to Cupertino - apple design)
• It's a good pratice to keep one widget per file
• Widgets by category: https://docs.flutter.dev/development/ui/widgets
• Widgets searchable: https://api.flutter.dev/

StatelessWidget

• .build() renders the UI.
• External data can be provided by passing value to the widget constructor
• No internal state

StatefulWidget

• Has an internal state
• As soon that the internal state is changed using setState() the widget is rerendered automatically
• setState() calls .build() of the widget again. But flutter is smart enough to update only the nested widgets that have been changed
• Repainting a widget is different from recreating a widget

Buttons

• ElevatedButton
• TextButton
• OutlinedButton
• FloatingActionButton

• IconButton

• Deprecated buttons

• RaisedButton -> ElevatedButton
• FlatButton -> TextButton
• OutlineButton -> OutlinedButton