Null Safety in Flutter & Dart

We will examine the Null Safety Support for Flutter & Dart in this article. We’ll examine how null safety is implemented in Flutter, how it affects the development process, what advantages it offers, and how to switch your flutter applications over to null safety.

  • What is null safety

To prevent null-dereference mistakes from occurring at runtime because they were identified and resolved at compile time, sound null safety makes types in code non-nullable by default and enables exceptional static checks and compiler upgrades.

Sound Null pointer-related issues are eliminated by null safety. It naturally renders types in your Dart code non-nullable. It indicates that unless you explicitly state otherwise, factors cannot contain null. The null safety of Dart is solid. This suggests that Dart is positive that the records list and all of its elements cannot be null. If you examine your running code in the debugger, you’ll find that non-nullability is maintained during runtime. When Dart analyses your code and determines that a variable is non-nullable, that variable is continuously non-nullable.

Contrarily, certain distinct executions are invalid, and frequently, runtime null checks are required. Dart gives Swift good null safety, but not many other programming languages. When the sort framework determines that something isn’t null, you can trust it since it can never make a mistake. This is what it means to be sound. Soundness can only be achieved if all of the libraries you utilise for the task contain null-safe code.

Another positive effect of Dart’s null safety is that your projects can be smaller and completed more quickly. Dart can be improved because it is pretty certain that files are rarely null. For instance, because it doesn’t need to include checks for nulls when it realises a variable isn’t null, the Dart early (AOT) compiler can produce minimal and speedier local code.

  • Why null safety

Dart is a type-safe language. This implies that the compiler can ensure that a variable or something like you get is of that sort. Nevertheless, type safety on its own does not ensure that the variable is not null.
Null issues are incredibly common. A search on GitHub turns up a tonne of problems caused by unexpected nulls in Dart code, and surprisingly more great many offer solutions to remedy those problems. Try to see if you can see the nullability problems in the corresponding Flutter application.

  • Principles of null safety


Variables cannot be null in the Dart programming language without explicit nullability declarations.


Making the switch to null safety is entirely up to you. When and what to shift to null safety is entirely up to you. Null-safe and non-null-safe code stages are possible in the same project.

Fully Sound

Dart’s null safety feature makes it possible for compiler improvements. All variables that demand values must be properly initialised. Null Safety also offers the advantages of fewer bugs, smaller binaries, and quicker execution.

  • Nullable and non-nullable types

Non-nullable types

All types are by default non-nullable when null safety is used. For instance, an integer value is required for an int variable.

void main() {
  int number;
  number = 0; 

A non-nullable variable must always be assigned a non-null value.

Nullable types

The following operators indicate whether a variable could be null:

Nullable type (?)

String? userName;  // By default, it's set to null.
int? age = 25;  // By default, it's set to non-null.
age = null; // It's possible to reassign it to null.

It’s not necessary to initialise a nullable variable before using it.

The assertion operator (!)

A nullable statement that isn’t null can be treated as non-nullable in Dart by using the null assertion operator “!” You must, however, confirm that it does not have a value.

int? age = 50;
int data = age!; // Because the value is not nullable, this is valid

Type promotion

An algorithm that determines how a programme will run is called flow analysis.

The Dart analyzer searches for variables that are nullable yet have non-null values and alerts the developer of any potential compile-time issues.

int getValue(int? value) {
  if (value == null) {
  // here the value is not null.
  return value;
void main(){

This code ascertains whether or not a value is null. A value that cannot be nullified is non-nullable.



Submit a Comment

Your email address will not be published. Required fields are marked *


Select Categories