1. 主函數(shù)

(1)?沒有public static

(2) 命令參數(shù)List args

voidmain() {

}

2. 可以在class外定義變量，方法等

3. 沒有public, private, protected關(guān)鍵字

4. 創(chuàng)建對象，new可選

5. 獲取值${variableValue}, ${expression}

6. Class中屬性默認(rèn)public，若聲明私有，只需在屬性名前加_

classBicycle {intcadence;int _speed = 0;int get speed =>_speed;intgear;

Bicycle(this.cadence, this.gear);void applyBrake(intdecrement) {

_speed-=decrement;

}void speedUp(intincrement) {

_speed+=increment;

}

@override

String toString()=> 'Bicycle: $_speed mph';

}voidmain() {

var bike= Bicycle(2, 1);

print(bike);

}

7. getter/setter方法

//返回值類型/get/外部可訪問屬性/方法體

int get speed => _speed

//set/外部可訪問屬性(值)/方法體

set speed(int value) => _speed = value;

8. 未初始化的變量值均為null

9. 構(gòu)造函數(shù)簡化，避免重載

import 'dart:math';classRectangle {

Point origin;

num width;

num height;

Rectangle({this.origin = const Point(0, 0), this.width = 0, this.height = 0});

@override

String toString()=> 'Origin: (${origin.x}, ${origin.y}), width: $width, height: $height';

}voidmain() {

print(Rectangle(origin:const Point(3,4), width: 10, height: 20));

print(Rectangle(origin:const Point(10,20)));

print(Rectangle(width:20));

print(Rectangle());

}

10. 一個(gè)dart文件中可以定義多個(gè)class，也可以僅僅定義方法

//factory.dart

import 'shapes.dart';

Shape shapeFactory(String type){if(type == 'circle') return Circle(2);if(type == 'square') return Square(2);throw 'Can\'t create $type';

}

11. 字符串可用單引號或者雙引號

12. 工廠構(gòu)造函數(shù) => 在抽象類中定義工廠函數(shù)，規(guī)定子類實(shí)例化方式

abstract classShape {//factory constructor

factory Shape(String type){if(type == 'circle') return Circle(10);if(type == 'square') return Square(10);throw 'can\'t create $type';

}

num get area;

}

13. Dart中沒有interface關(guān)鍵字，每個(gè)類都可以做接口

import 'shapes.dart';class CircleMock implementsCircle {

num area;

num radius;

}

//A person. The implicit interface contains greet().

classPerson {//In the interface, but visible only in this library.

final_name;//Not in the interface, since this is a constructor.

Person(this._name);//In the interface.

String greet(String who) => 'Hi $who, I\'m $_name';

}//An implementation of the Person interface.

class Impostor implementsPerson {

@override

String get _name=> this._name;

@override

String greet(String who)=> 'Hi $who, do you know who I am?';

}//polymorphism

String greetBob(Person person) => person.greet('Bob');

main() {

print(greetBob(Person('chris')));

print(greetBob(Impostor()));

}

14. 同一對象級聯(lián)操作

通過..符號可以在同一對象上級聯(lián)操作。

querySelector('#confirm') //Get an object.

..text = 'Confirm' //Use its members.

..classes.add('important')

..onClick.listen((e)=> window.alert('Confirmed!'));

15. 函數(shù)無需聲明可能拋出的異常類型

16. 捕獲異常

try{//···

} on Exception catch(e) {

print('Exception details:\n $e');

}catch(e, s) {

print('Exception details:\n $e');

print('Stack trace:\n $s');

}

17. 在運(yùn)行時(shí)，Dart保留泛型類型信息

var names = List();

names.addAll(['Seth', 'Kathy', 'Lars']);

print(names is List); //true

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