Coding All-in-One For Dummies, 2nd Edition

Chapter 4

Hello Again

IN THIS CHAPTER

Looking at functions in a Flutter app

Learning to type

Dealing with variables and other little things

♪ “Hello, hello again, sh-boom and hopin' we'll meet again.” ♪

—JAMES KEYES, CLAUDE FEASTER, CARL FEASTER, FLOYD F. MCRAE, AND JAMES EDWARDS, SUNG BY THE CHORDS, THE CREW-CUTS, STAN FREBERG, AND OTHERS, 1954

Chapter 3 is all about a simple Hello World program. Listing 4-1 shows one version of the code.

LISTING 4-1: Yet Another Look at the First Hello Program

import 'package:flutter/material.dart';main() => runApp(App0401());class App0401 extends StatelessWidget { Widget build(BuildContext context) { return MaterialApp( home: Material( child: Center(child: Text("Hello world!")), ), ); }}

In Chapter 3, you focused on the middle of the program — the MaterialApp and all the stuff inside it — while ignoring anything having to do with things called “functions.” This chapter continues the tour of a Hello World program and sets its sites on those “function” things.

Creating and Using a Function

Here's an experiment: Run the app whose code is shown in Listing 4-2.

LISTING 4-2: Words, Words, Words

import 'package:flutter/material.dart';main() => runApp(App0402()); ...