Dart and Flutter
- Flutter course
- Beginner
- Lesson 2/99
- 4 min
Learn that Flutter uses the Dart language and why this pair was chosen.
The Dart language
Flutter apps are written in Dart. Dart is also an object-oriented, statically typed language developed by Google. During development a JIT compiler enables hot reload in seconds; for release builds an AOT compiler compiles directly to machine code.
String isim = 'Ada'; // cannot be null
String? takmaAd; // can be nullSound null safety
Dart's sound null safety separates nullable values from non-nullable ones at the type level. Adding ? after a type allows null; without it the compiler rejects null assignments. Null reference errors are caught before they crash the app.
int yas = 25; // cannot be null
int? puan; // can be null
puan = null; // validPractice Null safety variables
In main, declare int yas = 25. Declare String? takmaAd and assign null. Then print yas and takmaAd with print.
Starter code
void main() {
// yas adında null olamayan int tanımla ve 25 ata
// takmaAd adında null olabilen String tanımla, null ata
// yas ve takmaAd'ı print ile yazdır
}Sample solution
void main() {
int yas = 25;
String? takmaAd;
takmaAd = null;
print(yas);
print(takmaAd);
}Expected output
25 null
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Why did Flutter choose Dart?
- It does not support classes or inheritance
- It requires no compilation step
- JIT for hot reload and AOT for fast release builds Correct answer
- It was designed only for web pages
Explanation: Dart's JIT and AOT modes give Flutter fast development and efficient release builds.
2 Nullable type
int____ sayac;int? sayac;Explanation: Adding ? after a type allows null values.
3 Dart and Flutter
| Term | Meaning |
|---|---|
JIT |
Enables hot reload in development |
AOT |
Compiles release builds to machine code |
Sound null safety |
Prevents null reference errors |
Dart |
Flutter's programming language |