- This widget sets up a basic layout in android to show some output.
- The background is black in color and text styling by default doesn't look neat.
homeis a required argument forMaterialApp.Textwidget can be passed tohometo show some basic text.
- This creates a basic white background for the app.
appbarwill create a appbar at the top.- Pass widget to
bodyto show the content to the main screen.
- To pass multiple widgets use
columnwhich takes a list of widgets.
- To create a button.
onPressedis a required argument(will get a warning if not used).- A function can be passed to
onPressedto do some action.
- We have created a list of questions and button increases a count so that we can show the questions in the list.
- But the count increases but doesn't gets updated in the screen.
- It is because the widget is stateless.
- To overcome this problem(recreate UI when state changes) we need to change the widget to a stateful widget.
- Two classes create a stateful widget:
Stateclass (along with pointer to the Widget class) to persist dataStatefulWidgetclass to recreate widget on state change
Stateclass is created as private class to prevent using it from other files.- Connection is created between State class and Widget class.
- Value is updated in
setStateclass method given byStateclass. setStatetakes a anonymous function.setStateforces flutter to re-render the widget (only in which the state has changed).- Now if the data or state changes the widget gets recreated.
- In
styleargument we can passTextStylewidget to add styling like size, font, etc. textAlignargument takes an enumTextAlign. But since the Text widget takes the size only needed for text, it wont work unless we put it in a container and add some width to the text.
- enums
- multiple constructors
- Map or {} (like dictionary in python)
- .toList() - Used to convert a iterable(output of map) to a list.
- ...list - used to spread list of items into individual items.
finalis runtime constant - We won't change once instantiated(runtime)constis compile time constant - We won't change once assigned(during coding)var numbers = const [1,2,3]makes the list(value) immutable.
- Created a quiz app with score display and quiz reset.
- Basics of Dart
- Basics of flutter
React
Typescript
Django
Laravel
Facebook
Microsoft
Google
Alibaba
D3
Tencent