Writing main
Let’s start from the simplest and least specific part of our app: the main function.
Using a Wrapper Class
In the previous chapter we defined a MyApp class and used main simply to run it, in the following way:
| | void main() => |
| | runApp(MyApp()); |
| | |
| | class MyApp extends StatelessWidget { |
| | @override |
| | Widget build (BuildContext context) { |
| | return MaterialApp( |
| | // Actual app content and data |
| | ); |
| | } |
| | } |
Skipping the Wrapper Class
The same effect would be achieved by simply writing:
| | void main() { |
| | runApp(MaterialApp( |
| | // other app content and data |
| | )); |
| | } |
This looks a lot shorter, but in a larger app it isn’t really much by comparison.
If your app is entirely contained in one view it doesn’t compromise app functionality, but if you need more views and need to have shared data you should consider writing a wrapper class for your app to keep things organized and clear.
And, in any case, you should only use the second form if you really need to keep your code compact or to save time to quickly write a small app.
So we will write the following:
| | void main() => runApp(MyApp()); |
| | |
| | class MyApp extends StatelessWidget { |
| | @override |
| | Widget build(BuildContext context) { |
| | return MaterialApp( |
| | title: "Flutter Calculator", |
| | theme: ThemeData( |
| | primarySwatch: Colors.blue, |
| | backgroundColor: Colors.black26 |
| | ), |
| | home: CalculatorHomePage(title: "Flutter Calculator", ), |
| | ); |
| | } |
| | } |
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