Dart Awesome Cheat Sheet for Flutter Beginners

If you are really interested in cross-platform development, you know about a new kid in a block — Flutter. Google’s new mobile app SDK which allows developers to write beautiful, natively compiled applications for mobile, web, and desktop right from a single codebase. There has been an increasing number of tech companies who have decided to develop their multi-platform apps using flutter framework. As a result, the demand for flutter developers in the tech industry has drastically increased over the past 2 years. In order to meet this demand, it’s essential we have a huge community of passionate flutter devs willing to develop world class apps without any sort of programming barriers.

In this article, I will share with you 4 major dart cheats that will help you quickly get started with flutter development.

String interpolation

Every language has its own way of interpolating two or more words or characters. In dart, you can put the value of an expression inside a string as follows:

int x=6;
   int y=2;
   String sum = '${x+y}';          // result is 8
   String subtraction = '${x-y}';  // result is 4
   String upperCase = '${"hello".toUpperCase()}'; // result is HELLO
   String concatXY = '$x$y'; // result is '62'

Functions

Dart lang is an OOL(Object-oriented language). In this language, functions are objects and have a type, Function. This implies that functions can be assigned to variables or passed as args to other functions. Interestingly, you can also call an instance of a class as if it were a function. That’s awesome, right?

String fullName(){
       String firstName = "Temidayo";
       String lastName = "Adefioye";
       return '$firstName $lastName'; // returns 'Temidayo Adefioye'
   }

int length(String text){
       return text.length; // returns length of text
   }

The above function can be rewritten in a more concise way:

int length(String text) => return text.length; // returns length of text

The above approach is applicable where functions contain just ONE expression. This is also referred to as shorthand syntax.

Null-aware Operators

Handling null exceptions in app development is very essential, as this allows you to create a seamless experience for your app users. Dart provides you with some handy operators for dealing with values that might be null. One is the ??= assignment operator, which assigns a value of a variable only if that variable is currently null:

int x; // The initial value of any object is null
   x ??=6;
   print(x); // result: 6

   x ??=3;
   print(x); // result is still 6

   print(null ?? 10); // result: 10. Display the value on the left if it's not null else return the value on the right

List Arrays

Perhaps the most common collection in nearly every programming language is the array or ordered set of objects. Please note that Dart arrays are Lists.

var numList = [1,2,3,5,6,7];
   var countryList = ["Nigeria","United States","United Kingdom","Ghana","IreLand","Germany"];
   String numLength = numList.length; // result is 6
   String countryLength = countryList.length; // result is 6
   String countryIndex = countryList[1]; // result is 'United //States'
   String numIndex = numList[0]; // result is 1

   countryList.add("Poland"); // Adds a new item to the list.

   var emailList = new List(3); // Set a fixed list size 
   var emailList = new List<String>(); // instance of a list of type //String

Would that be all?

No!

I have carefully curated an awesome cheat sheet for developers who are interested in developing apps using flutter and dart.

You can find this cheat sheet here

In the coming weeks, the sheet will be updated with more awesome dart cheats.

Happy Fluttering!