Flutter Mobile Development · 课时

Flutter 所需的 Dart 基础

深入学习 Dart 编程基础，涵盖变量、数据类型、控制流、函数以及 Flutter 所需的面向对象概念。

Flutter 所需的 Dart 基础 是 CoddyKit 上的免费 Flutter Mobile Development 课时。这是第 2 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 Flutter Mobile Development 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Flutter Mobile Development 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

Welcome to Dart!

Before building apps, let’s learn Dart — Flutter’s language. It’s client-optimized and quick to pick up if you know Java or JavaScript.

Storing Data: Variables & Types

Variables store data. Declare them with var for inferred types, or be explicit: int, double, String, bool.

Variables in Action

Here’s declaring different variable types. Note Dart’s null safety: a variable can’t be null unless you opt in with ?.

void main() {
  var name = "Alice"; // Type inferred as String
  int age = 30;
  double height = 1.75;
  bool isStudent = true;
  String? middleName; // Can be null

  print("Name: $name");
  print("Age: $age");
  print("Student: $isStudent");
}

Grouping Data: Lists

A Dart List is an ordered, zero-indexed collection — like an array. Declare a typed one like List<String> and grab items by position.

void main() {
  List<String> fruits = ['Apple', 'Banana'];
  print('Initial fruits: $fruits');

  fruits.add('Orange'); // Add an item
  print('After adding: $fruits');

  print('First fruit: ${fruits[0]}');
}

Making Decisions: If/Else

Control flow lets your code decide. if runs when a condition is true; chain else if and else for the rest.

void main() {
  int temperature = 25;

  if (temperature > 30) {
    print('It\'s very hot!');
  } else if (temperature > 20) {
    print('It\'s warm.');
  } else {
    print('It\'s cool.');
  }
}

Repeating Actions: Loops

Loops repeat a block. A for loop is perfect for iterating a list or running a task a fixed number of times.

void main() {
  List<String> colors = ['Red', 'Green', 'Blue'];

  for (String color in colors) {
    print('Color: $color');
  }

  for (int i = 0; i < 3; i++) {
    print('Count: $i');
  }
}

Functions: Reusable Code

Functions are reusable blocks that do one task. They take parameters as input and can return a value as output.

Defining & Calling Functions

This shows two functions: greet takes a name, add returns an int. void means a function returns nothing.

void greet(String name) {
  print('Hello, $name!');
}

int add(int a, int b) {
  return a + b;
}

void main() {
  greet('Coddy');
  int sum = add(10, 5);
  print('Sum: $sum');
}

Basic Classes & Objects

Dart is object-oriented: a class is a blueprint for objects. Objects bundle properties (data) and methods (behavior) to keep code organized.

class Car {
  String brand; // Property
  int year;    // Property

  Car(this.brand, this.year); // Constructor

  void displayInfo() { // Method
    print('$brand from $year');
  }
}

void main() {
  var myCar = Car('Toyota', 2020); // Create an object
  myCar.displayInfo(); // Call a method

  var otherCar = Car('Honda', 2022);
  otherCar.displayInfo();
}

Dart Fundamentals Check

Which of the following Dart code snippets are valid variable declarations or initializations?

Recap: Dart Essentials

Nice work! You’ve got Dart’s core building blocks — variables, lists, control flow, loops, functions, and classes. This is the foundation for every Flutter app.

常见问题解答

「Flutter 所需的 Dart 基础」课时是免费的吗？

是的 — 「Flutter 所需的 Dart 基础」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Flutter Mobile Development 课程的其余内容，请升级到 CoddyKit PRO。 Flutter Mobile Development 课程共包含 4 节课。

「Flutter 所需的 Dart 基础」这节课中我会学到什么？

深入学习 Dart 编程基础，涵盖变量、数据类型、控制流、函数以及 Flutter 所需的面向对象概念。你通过在浏览器中直接运行的动手代码来练习 Flutter Mobile Development，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 Flutter Mobile Development 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Flutter Mobile Development 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 2 节课，共 4 节。

「Flutter 所需的 Dart 基础」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 Flutter Mobile Development 课中编写并运行代码吗？

能。每节 Flutter Mobile Development 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

此课程中的所有课时

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