目录
常量
Object-C
const int a = 10;
Swift
let a: Int = 10 //不要求编译时确定，如果声明时没有值需要指定类型
let a = 10 //可以省略类型说明和结尾的分号
JavaScript
const a = 10
Flutter
const int a = 10; //编译时确定
const a = 10; //int 可以省略
finial int a = 10; //运行时确定
变量与数据类型
Object-C
BOOL isClick = NO;
int a = 0; float a = 10.0;
NSString *str = @"hello world";
NSArray *array = @[@(1), @(2), @(3)];
NSDictionary *dic = @{@"key1":@"valu1", @"key2": @"value2"}
XYPerson *person = [[XYPerson alloc] initWithName:@"xiaoming" age:18];
// 匿名函数
int(^blk)(int a, NSString* str) = ^int(int a, NSString* str){ return 10;};
// 函数
-(int)sumWithNumA:(int)numA numB:(int)numB;
Swift
var isClick:Bool = false //可以省略类型说明和结尾的分号
var a:Int = 0; var a:Float = 10.0; a:Double = 10.0;
var str:String = "hello world"
var cha:Character = "a" // 字符类型必须指定类型
var array:Array = [1, 2, 3, 4]
var dic : Dictionary = ["key1":"value1", 1:"value2"]
var set:Set = ["age","weight"]
// 元组
let error = (404, "Not Fount")// error.0
let error = (code:404, msg:"Not Fount")//error.code
//对象类型
let p:Person = Person(name:"xiaoming",age:18)
//匿名函数:闭包表达式，可以作为参数，尾随闭包的调用
var blk:(Int,Int)->Int = {(a, b) in return a + b} // var result = blk(10,20)
//函数
func sum(a:Int, b:Int)->Int {return 10}
func goToWork(at time:String){} // goToWork(at:"10:00")
JavaScript
let isClick = false
let a = 0
let str = 'hello world'
let array = [1, 2, 3]
let dic = {key1:'value1', key2:'value2'}
let person = new Person('xiaoming', 18)
undefine
// 匿名函数
let blk = (a, str)=>{ return 10 }
let blk = function(a, str){ return 10}
// 函数
function sum (numA, numB) {}
Flutter
bool isClick = false;
var isClick = false; //可以使用var 自动推断类型
int a = 10; double a = 10.0; num a = 10;
String str = 'hello world';
List array = [1, 2, 3]
Map dic = {'key1': 'hank', 'key2': 10};
Person person = Person('xiaoming', 18);
// 匿名函数
var blk = (a, str){return 10;}
// 函数:参数类型和返回值类型可以省略
int sum (numA, numB){}
分支结构
Object-C
int a = 10
if ( a > 10){
} else if (a > 5) {
} else {
}
switch (a) {
case 10:
break;
case 5:
break;
default:
}
Swift
var a = 10
if a > 10 {
} else if a > 5 {
} else {
}
switch a {
case 10 :
case 5 :
default:
}
JavaScript
let a = 10
if ( a > 10){
} else if (a > 5) {
} else {
}
switch (a) {
case 10:
break;
case 5:
break;
default:
}
Flutter
int a = 10
if ( a > 10){
} else if (a > 5) {
} else {
}
switch (a) {
case 10:
break;
case 5:
break;
default:
}
循环结构
Object-C
for (NSNumber *num in arary) {}
for (int i = 0; i < length; i++){}
while(YES){}
Swift
for i in 1...3 {}
for i in array {}
for i in 1..<array.count {}
while true {}
JavaScript
for (let key in array) {}
for (let i = 0; i < length; i++){}
while (true) {}
Flutter
for (int num in arary) {}
for (int i = 0; i < length; i++){}
while(YES){}
面向过程和面向对象
JavaScript 面向过程
Object-C 面向对象:封装、继承、多肽
构造方法:
-(void)init; //构造方法
-(void)dealloc; //析构方法
实例属性:
@property (nonatomic, assign) NSString* name;
实例方法:
-(int)sumWithNumA:(int)numA numB:(int)numB;
静态属性:
无
静态方法:
+(int)sumWithNumA:(int)numA numB:(int)numB;
继承:
@interface Animal : NSObjec
@end
@interface Dog : Animal
@end
[super init];
Flutter 面向对象:封装、继承、多肽
构造方法:
Person(this.name, this.age) : sexy = true, assert(age >= 0); // 后边跟着初始化列表 和 断言
Person.all(this.name, this.age, this._height, this._hobby) : sexy = true; //命名构造方法
实例属性:
String name;
int _height;
计算属性:
float get whithVsHeight { return 0.5;} // 没有参数列表 本质是方法
实例方法:
int sum(numA, numB){ return 10;}
int _sum(numA, numB){ return 10;}
静态属性：
static int? num;
静态方法：
static int sum(numA, numB){ return 10;}
继承:
class Animal {}
//abstract class Animal{} // 抽象类：接口/协议
class Dog extends Animal {}
行者常至，为者常成！