Part 3 | Dart Functions, Named Parameters | Flutter Malayalam Tutorial Series

Introduction

In this tutorial, we will explore Dart functions and named parameters, crucial concepts for developing applications in Flutter. Understanding these fundamentals will enhance your programming skills and streamline your app development process. Whether you are a beginner or looking to sharpen your knowledge, this guide will provide you with clear, actionable steps to grasp these concepts effectively.

Step 1: Understanding Functions in Dart

Functions are blocks of code that perform a specific task. They are reusable and can take inputs and return outputs.

How to Define a Function

• Use the following syntax to define a function:

returnType functionName(parameterType parameterName) {
  // Function body
}

• Example of a simple function:

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

Practical Tips

• Choose descriptive names for your functions to make your code more readable.
• Keep functions short and focused on a single task.

Step 2: Function Parameters

Dart allows you to pass parameters to functions. There are two types of parameters: positional and named.

Positional Parameters

• These are the most common type of parameters.
• They must be provided in the order they are defined.

Named Parameters

• Named parameters are enclosed in curly braces {}.
• They allow you to specify parameters by name, improving code clarity.

How to Define Named Parameters

• Use the following syntax for named parameters:

void functionName({parameterType parameterName}) {
  // Function body
}

• Example with named parameters:

void greet({String name, int age}) {
  print("Hello, my name is $name and I am $age years old.");
}

• Calling the function:

greet(name: "John", age: 30);

Practical Tips

• Use named parameters when you have multiple optional parameters to avoid confusion.
• Default values can be assigned to named parameters for increased flexibility:

void greet({String name = "Guest", int age = 18}) {
  print("Hello, my name is $name and I am $age years old.");
}

Step 3: Returning Values from Functions

Functions can return values, which can be used in other parts of your code.

How to Return Values

• Use the return statement to send a value back to the caller.
• Ensure that the return type of the function matches the type of the value being returned.

Example

String getGreeting(String name) {
  return "Hello, $name!";
}

Conclusion

In this tutorial, we covered the basics of Dart functions and named parameters. You learned how to define functions, use positional and named parameters, and return values from functions. Mastering these concepts will greatly enhance your ability to create efficient and readable code in Flutter.

Next Steps

• Practice defining your own functions and using named parameters in small projects.
• Explore more advanced topics such as higher-order functions and anonymous functions to further deepen your Dart knowledge.