Hello, world ?. Ok on this occasion I will share a cheat sheet for those of you who want to learn the DART Programming Language or want to learn Flutter.
1. The First lesson (Hello World By Force)
// Lesson 1 in dart we must wrapper our code in the main
void main() {
for (int i = 0; i < 7; i++) {
print('Hello, World ${i + 1}');
}
}
2. The Second lesson (Function In Dart Side)
// Define the basic function
// Call the parameter
printNumber(num whichNumber) {
print('The number is $whichNumber');
}
// Calll on main function dart
void main() {
var num = 11;
printNumber(num);
}
3. The Third lesson (Declare War in Dart)
//How to declare variables on Dart
void main() {
int age = 20; //This is for declare number
String name = 'John Doe'; //This is string
bool isMale = true;
double height = 168.8;
// Final type
const data = 'This is final data';
final gender = 'Male';
// Common variable
var country = 'Indonesia';
// List is synonym with an Array
var list = [1, 2, 3];
// Maps is synonym with an Object
var profile = {
// A map literal
// Keys Values
'firstName': 'zidni',
'lasNam': 'ridwan nulmuarif',
'gender': 'male'
};
// Print here for test the variables
print(profile);
}
4. The Fourth lesson (More Function In Dart Spirit)
void main() {
int num1 = 12;
int num2 = 8;
printNumber(num1, num2);
//Call function 2 (We looping the data)
var list = [1, 2, 3];
list.forEach(printElement);
//Call the function 3
var add2 = makeAdder(2); // Create a function that adds 2.
var add4 = makeAdder(4); // Create a function that adds 4.
assert(add2(3) == 5);
assert(add4(3) == 7);
}
// function 1
void printNumber(num number1, number2) {
print(number1 + number2);
}
// function 2
printElement(element) {
print(element);
}
//Function 3
Function makeAdder(num n) {
return (num i) => n + i;
}
5. The Fifth lesson (Operator is Weapon)
// Operator on Dart
// unary postfix and argument definition test expr++ expr-- () [] . ?identifier
// unary prefix multiplicative
// additive
// shift
// relational and type test equality
// bitwise AND bitwise XOR bitwise OR logical AND logical OR conditional cascade assignment
// -expr !expr ~expr ++expr --expr * / % ~/
// + -
// << >>
// >= > <= == !=
// &
// ^
// < as
// is is!
// |
// &&
// ||
// expr1 ? expr2 : expr3
// .. =*=/=~/=%=+=-=<<=>>=&=^=|=
void main() {
var z = 2;
print(z + z);
print(z / z);
print(z * z);
print(z - z);
print(z = z);
print(z != z);
print(z % z);
print(z < z);
print(z > z);
print(z >= z);
print(z <= z);
print(z | z);
}
6. Sixth lesson (Control Your Mind)
// Control Flow
void main() {
// if else
bool hasRedHair = true;
if (hasRedHair) {
print('Erope');
} else {
print('Asia, Africa');
}
// For loop
var listData = [1, 2, 3, 4, 5];
for (var x in listData) {
print(x);
}
// While and Do-While
int number = 0;
do {
if (number % 2 == 0) {
print(number);
}
number++;
} while (number < 10);
// Switch Case
var command = 'OPEN';
switch (command) {
case 'CLOSED':
print('Please Open The Door');
break;
case 'PENDING':
print('Door Will Be Open');
break;
case 'OPEN':
print('Door Already Open');
break;
case 'DENIED':
print('You Can`t in because Door is lock');
}
}
7. The Seventh lesson (Assert You're Dream)
// Use an assert statement to disrupt normal execution if a boolean condition is false.
// You can find examples of assert statements throughout this tour. Here are some more:
void main() {
String text = 'May the force be with you!';
assert(text != null);
}
8. The Eighth lesson (Exceptions in goodness)
// Dart code can throw and catch exceptions. Exceptions are errors indicating that something unexpected happened.
void main() {
int x = 11;
int y = 0;
int res;
try {
res = x ~/ y;
} on IntegerDivisionByZeroException {
print('Cannot divide by zero');
}
exception();
exceptionWithFinaly();
}
// Try catch with exception
exception() {
int x = 10;
int y = 0;
int res;
try {
res = x ~/ y;
} catch (e) {
print(e);
}
}
// With finaly
exceptionWithFinaly() {
int x = 9;
int y = 0;
int res;
try {
res = x ~/ y;
} on IntegerDivisionByZeroException {
print('Cannot divide by zero');
} finally {
print('Finally block executed');
}
}
9. The Ninth lesson (Classes and Universe Objects)
// Structure of Class in Dart
// class class_name {
// <fields>
// <getters/setters>
// <constructors>
// <functions>
// }
// Fields − A field is any variable declared in a class. Fields represent data pertaining to objects.
// Setters and Getters − Allows the program to initialize and retrieve the values of the fields of a class. A default getter/ setter is associated with every class. However, the default ones can be overridden by explicitly defining a setter/ getter.
// Constructors − responsible for allocating memory for the objects of the class.
// Functions − Functions represent actions an object can take. They are also at times referred to as methods.
void main() {
Car c = new Car();
c.desc();
}
class Car {
// field
String engine = "B1001";
String brand = "Ferari";
String owner = "Zidniryi";
int yearProd = 2025;
bool isColorRed = true;
// function or we can call Method
void desc() {
print(engine);
print(brand);
print(owner);
print(yearProd);
print(isColorRed);
}
}
10. The Tenth lesson (RegEx the Jedi)
/**
* A regular expression (regex or regexp for short) is
* a special text string for describing a search pattern.
* You can think of regular expressions as wildcards on steroids.
*/
void main() {
RegExp re = new RegExp(r'(\w+)');
String str1 = "one two three";
print('Has match: ${re.hasMatch(str1)}');
// First match
Match firstMatch = re.firstMatch(str1);
print('First match: ${str1.substring(firstMatch.start, firstMatch.end)}');
// Iterate all matches
Iterable matches = re.allMatches(str1);
matches.forEach((match) {
print(str1.substring(match.start, match.end));
});
}
11. The Eleventh lesson (List The Sith)
void main() {
// Use a List constructor.
// Or simply use a list literal.
var fruits = ['apples', 'oranges'];
// Add to a list.
fruits.add('kiwis');
print(fruits);
print(fruits.length);
// Add multiple items to a list.
fruits.addAll(['grapes', 'bananas']);
print(fruits);
// Get the list length.
assert(fruits.length == 5);
// Remove a single item.
var appleIndex = fruits.indexOf('apples');
fruits.removeAt(appleIndex);
assert(fruits.length == 4);
print(fruits);
// Remove all elements from a list.
fruits.clear();
assert(fruits.length == 0);
print(fruits);
}
12. The Twelfth lesson (Date of Yoda)
import 'package:moment/moment.dart';
//For install pubsec.yaml
//you can see in here => https://dart.dev/tools/pub/pubspec
void main() {
var now = new DateTime.now();
var berlinWallFell = new DateTime.utc(1989, 11, 9);
var moonLanding = DateTime.parse("1969-07-20 20:18:04Z");
print(now);
print(moonLanding);
Moment().add(1, Unit.day);
var dateStyle = Moment().format('yyyy-MM-dd');
print(dateStyle);
print(Moment().subtract(2, Unit.day));
}
}
13. The Thirteenth lesson (Asynchronous Future )
Future<void> getUser() {
return Future.delayed(Duration(seconds: 3), () => print('Big Data'));
}
void main() {
getUser();
print('Fetching user data...');
}
14. The Fourteenth lesson (Asynchronous Future Next Level)
import 'dart:io';
void main() {
print("Enter your name :");
// prompt for user input
String name = stdin.readLineSync();
// this is a synchronous method that reads user input
print("Hello Mr. ${name}");
print("End of main");
}
15. The Fifteenth lesson (Math Attack Clone)
import "dart:math" show pi;
void main() {
print(pi / 12);
}
}
16. The Sixteenth lesson (Make Lib And Call Skywalker)
// We create library
dart_lib(num1, num2) {
print(num1 + num2);
}
// We call the library
import '16.0dart_lib.dart';
void main() {
// call that
dart_lib(20, 20);
}
That's all for the lesson 😈😈😈😈😇😇😇. May The Force Be With You ...
For clone, You can clone in my GitHub : https://github.com/zidniryi/Dart-Vader
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