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查看新版教程,请访问 Angular 6.x 快速入门
Angular 是由谷歌开发与维护一个开发跨平台应用程序的框架,同时适用于手机与桌面。html
Controller
和 Scope
RxJS
与 Observable
Zone.js
,提供更加智能的变化检测基于 Angular Quickstartnode
基于 Angular CLIgit
本快速入门教程,选用第一种配置方式搭建 Angular 开发环境:github
Git
克隆 quickstart 项目git clone https://github.com/angular/quickstart ng4-quickstart
IDE
打开已新建的项目 (本教程使用的 IDE 是 Visual Studio Code)code ./ng4-quickstart
npm i
npm start
npm install -g @angular/cli
ng --version
ng new PROJECT-NAME
cd PROJECT-NAME ng serve
在 Angular 中,咱们可使用 {{}}
插值语法实现数据绑定。typescript
import { Component } from '@angular/core'; @Component({ selector: 'my-app', template: `<h1>Hello {{name}}</h1>`, }) export class AppComponent { name = 'Angular'; }
import { Component } from '@angular/core'; @Component({ selector: 'my-app', template: ` <h2>你们好,我是{{name}}</h2> <p>我来自<strong>{{address.province}}</strong>省, <strong>{{address.city}}</strong>市 </p> `, }) export class AppComponent { name = 'Semlinker'; address = { province: '福建', city: '厦门' } }
值得一提的是,咱们可使用 Angular 内置的 json
管道,来显示对象信息:shell
@Component({ selector: 'my-app', template: ` ... <p>{{address | json}}</p> `, }) export class AppComponent { name = 'Semlinker'; address = { province: '福建', city: '厦门' } }
在 Angular 中,咱们能够经过 Component
装饰器和自定义组件类来建立自定义组件。npm
在 Angular 中,咱们可使用 Component
装饰器来定义组件的元信息:json
@Component({ selector: 'my-app', // 用于定义组件在HTML代码中匹配的标签 template: `<h1>Hello {{name}}</h1>`, // 定义组件内嵌视图 })
export class AppComponent { name = 'Angular'; }
在 TypeScript 中的接口是一个很是灵活的概念,除了可用于对类的一部分行为进行抽象之外,也经常使用于对「对象的形状(Shape)」进行描述。bootstrap
interface Person { name: string; age: number; } let semlinker: Person = { name: 'semlinker', age: 31 };
import { Component } from '@angular/core'; @Component({ selector: 'sl-user', template: ` <h2>你们好,我是{{name}}</h2> <p>我来自<strong>{{address.province}}</strong>省, <strong>{{address.city}}</strong>市 </p> ` }) export class UserComponent { name = 'Semlinker'; address = { province: '福建', city: '厦门' }; }
// ... import { UserComponent } from './user.component'; @NgModule({ imports: [ BrowserModule ], declarations: [ AppComponent, UserComponent], bootstrap: [ AppComponent ] }) export class AppModule { }
import { Component } from '@angular/core'; @Component({ selector: 'my-app', template: ` <sl-user></sl-user> `, }) export class AppComponent {}
@Component({...}) export class UserComponent { name: string; address: any; constructor() { this.name = 'Semlinker'; this.address = { province: '福建', city: '厦门' } } }
interface Address { province: string; city: string; }
export class UserComponent { name: string; address: Address; // ... }
在 Angular 实际项目中,最经常使用的指令是 ngIf
和 ngFor
指令。segmentfault
该指令用于根据表达式的值,动态控制模板内容的显示与隐藏。它与 AngularJS 1.x 中的 ng-if
指令的功能是等价的。
<div *ngIf="condition">...</div>
该指令用于基于可迭代对象中的每一项建立相应的模板。它与 AngularJS 1.x 中的 ng-repeat
指令的功能是等价的。
<li *ngFor="let item of items;">...</li>
import { Component } from '@angular/core'; interface Address { province: string; city: string; } @Component({ selector: 'sl-user', template: ` <h2>你们好,我是{{name}}</h2> <p>我来自<strong>{{address.province}}</strong>省, <strong>{{address.city}}</strong>市 </p> <div *ngIf="showSkills"> <h3>个人技能</h3> <ul> <li *ngFor="let skill of skills"> {{skill}} </li> </ul> </div> ` }) export class UserComponent { name: string; address: Address; showSkills: boolean; skills: string[]; constructor() { this.name = 'Semlinker'; this.address = { province: '福建', city: '厦门' }; this.showSkills = true; this.skills = ['AngularJS 1.x', 'Angular 2.x', 'Angular 4.x']; } }
在 Angular 中,咱们能够经过 (eventName)
的语法,实现事件绑定。
<date-picker (dateChanged)="statement()"></date-picker>
等价于
<date-picker on-dateChanged="statement()"></date-picker>
介绍完事件绑定的语法,接下来咱们来为第五节中的 UserComponent
组件,开发一个功能,便可以让用户动态控制技能信息的显示与隐藏。
@Component({ selector: 'sl-user', template: ` ... <button (click)="toggleSkills()"> {{ showSkills ? "隐藏技能" : "显示技能" }} </button> ... ` }) export class UserComponent { // ... toggleSkills() { this.showSkills = !this.showSkills; } }
Angular 中有两种表单:
本小节主要介绍模板驱动式的表单,接下来咱们来演示如何经过表单来为咱们的以前建立的 UserComponent
组件,增长让用户自定义技能的功能。
import { FormsModule } from '@angular/forms'; // ... @NgModule({ imports: [BrowserModule, FormsModule], declarations: [AppComponent, UserComponent], bootstrap: [AppComponent] }) export class AppModule { }
<video #player></video> <button (click)="player.pause()">Pause</button>
等价于
<video ref-player></video>
@Component({ selector: 'sl-user', template: ` ... <div *ngIf="showSkills"> <h3>个人技能</h3> ... <form (submit)="addSkill(skill.value)"> <label>添加技能</label> <input type="text" #skill> </form> </div> ` }) export class UserComponent { // ... addSkill(skill: string) { let skillStr = skill.trim(); if (this.skills.indexOf(skillStr) === -1) { this.skills.push(skillStr); } } }
Angular 4.3 版本后,推荐使用 HttpClient,能够参考 Angular HTTP Client 快速入门
// ... import { HttpModule } from '@angular/http'; @NgModule({ imports: [BrowserModule, FormsModule, HttpModule], declarations: [AppComponent, UserComponent], bootstrap: [AppComponent] }) export class AppModule { }
(1) 从 @angular/http
模块中导入 Http 类
(2) 导入 RxJS 中的 map
操做符
(3) 使用 DI 方式注入 http 服务
(4) 调用 http 服务的 get()
方法,设置请求地址并发送 HTTP 请求
(5) 调用 Response 对象的 json()
方法,把响应体转成 JSON 对象
(6) 把请求的结果,赋值给对应的属性
import { Component, OnInit } from '@angular/core'; import { Http } from '@angular/http'; // (1) import 'rxjs/add/operator/map'; // (2) interface Member { id: string; login: string; avatar_url: string; } @Component({ selector: 'sl-members', template: ` <h3>Angular Orgs Members</h3> <ul *ngIf="members"> <li *ngFor="let member of members;"> <p> <img [src]="member.avatar_url" width="48" height="48"/> ID:<span>{{member.id}}</span> Name: <span>{{member.login}}</span> </p> </li> </ul> ` }) export class MembersComponent implements OnInit { members: Member[]; constructor(private http: Http) { } // (3) ngOnInit() { this.http.get(`https://api.github.com/orgs/angular/members?page=1&per_page=5`) // (4) .map(res => res.json()) // (5) .subscribe(data => { if (data) this.members = data; // (6) }); } }
// ... import { MembersComponent } from './members.component'; @NgModule({ imports: [BrowserModule, FormsModule, HttpModule], declarations: [AppComponent, UserComponent, MembersComponent], bootstrap: [AppComponent] }) export class AppModule { }
import { Component } from '@angular/core'; @Component({ selector: 'my-app', template: ` <sl-members></sl-members> `, }) export class AppComponent {}
(1) 配置已建立的服务,如:
@NgModule({ // ... providers: [MemberService] }) export class AppModule { }
(2) 导入已建立的服务,如:
import { MemberService } from '../member.service';
(3) 使用构造注入方式,注入服务:
export class MembersComponent implements OnInit { // ... constructor(private memberService: MemberService) { } }
import { Injectable } from '@angular/core'; import { Http } from '@angular/http'; @Injectable() export class MemberService { constructor(private http: Http) { } getMembers() { return this.http .get(`https://api.github.com/orgs/angular/members?page=1&per_page=5`) .map(res => res.json()) } }
import { MemberService } from "./member.service"; @NgModule({ // ... providers:[MemberService], bootstrap: [AppComponent] }) export class AppModule { }
// ... import { MemberService } from "./member.service"; @Component({...}) export class MembersComponent implements OnInit { members: Member[]; constructor(private memberService: MemberService) { } ngOnInit() { this.memberService.getMembers() .subscribe(data => { if (data) this.members = data; }); } }
// ... import { RouterModule } from '@angular/router'; @NgModule({ imports: [BrowserModule, FormsModule, HttpModule, RouterModule], declarations: [AppComponent, UserComponent, MembersComponent], bootstrap: [AppComponent] }) export class AppModule { }
import { Routes, RouterModule } from '@angular/router'; import { UserComponent } from './user.component'; export const ROUTES: Routes = [ { path: 'user', component: UserComponent } ]; @NgModule({ imports: [ BrowserModule, RouterModule.forRoot(ROUTES) ], // ... }) export class AppModule {}
为了让咱们连接到已设置的路由,咱们须要使用 routerLink 指令,具体示例以下:
<nav> <a routerLink="/">首页</a> <a routerLink="/user">个人</a> </nav>
当咱们点击以上的任意连接时,页面不会被从新加载。反之,咱们的路径将在 URL 地址栏中显示,随后进行后续视图更新,以匹配 routerLink
中设置的值。
该指令用于告诉 Angular 在哪里加载组件,当 Angular 路由匹配到响应路径,并成功找到须要加载的组件时,它将动态建立对应的组件,并将其做为兄弟元素,插入到 router-outlet
元素中。具体示例以下:
@Component({ selector: 'app-root', template: ` <div class="app"> <h3>Our app</h3> <router-outlet></router-outlet> </div> ` }) export class AppComponent {}
export const ROUTES: Routes = [ { path: '', pathMatch: 'full', redirectTo: 'user' }, { path: 'user', component: UserComponent }, { path: 'members', component: MembersComponent } ]; @NgModule({ imports: [BrowserModule, FormsModule, HttpModule, RouterModule.forRoot(ROUTES)], // ... }) export class AppModule { }
import { Component } from '@angular/core'; @Component({ selector: 'my-app', template: ` <div class="app"> <h1>欢迎来到Angular的世界</h1> <nav> <a routerLink="/user">个人</a> <a routerLink="/members">Angular成员</a> </nav> <router-outlet></router-outlet> </div> `, }) export class AppComponent { }
import { NgModule } from '@angular/core'; import { BrowserModule } from '@angular/platform-browser'; import { FormsModule } from '@angular/forms'; import { HttpModule } from '@angular/http'; import { RouterModule, Routes } from '@angular/router'; import { AppComponent } from './app.component'; import { UserComponent } from './user.component'; import { MembersComponent } from './members.component'; import { MemberService } from "./member.service"; export const ROUTES: Routes = [ { path: '', pathMatch: 'full', redirectTo: 'user' }, { path: 'user', component: UserComponent }, { path: 'members', component: MembersComponent } ]; @NgModule({ imports: [BrowserModule, FormsModule, HttpModule, RouterModule.forRoot(ROUTES)], declarations: [AppComponent, UserComponent, MembersComponent], providers: [MemberService], bootstrap: [AppComponent] }) export class AppModule { }
import { Component } from '@angular/core'; @Component({ selector: 'my-app', template: ` <div class="app"> <h1>欢迎来到Angular的世界</h1> <nav> <a routerLink="/user">个人</a> <a routerLink="/members">Angular成员</a> </nav> <router-outlet></router-outlet> </div> `, }) export class AppComponent { }
import { Component } from '@angular/core'; interface Address { province: string; city: string; } @Component({ selector: 'sl-user', template: ` <h2>你们好,我是{{name}}</h2> <p>我来自<strong>{{address.province}}</strong>省, <strong>{{address.city}}</strong>市 </p> <button (click)="toggleSkills()"> {{ showSkills ? "隐藏技能" : "显示技能" }} </button> <div *ngIf="showSkills"> <h3>个人技能</h3> <ul> <li *ngFor="let skill of skills"> {{skill}} </li> </ul> <form (submit)="addSkill(skill.value)"> <label>添加技能</label> <input type="text" #skill> </form> </div> ` }) export class UserComponent { name: string; address: Address; showSkills: boolean; skills: string[]; constructor() { this.name = 'Semlinker'; this.address = { province: '福建', city: '厦门' }; this.showSkills = true; this.skills = ['AngularJS 1.x', 'Angular 2.x', 'Angular 4.x']; } toggleSkills() { this.showSkills = !this.showSkills; } addSkill(skill: string) { let skillStr = skill.trim(); if (this.skills.indexOf(skillStr) === -1) { this.skills.push(skillStr); } } }
import { Component, OnInit } from '@angular/core'; import { Http } from '@angular/http'; import 'rxjs/add/operator/map'; import { MemberService } from "./member.service"; interface Member { id: string; login: string; avatar_url: string; } @Component({ selector: 'sl-members', template: ` <h3>Angular Orgs Members</h3> <ul *ngIf="members"> <li *ngFor="let member of members;"> <p> <img [src]="member.avatar_url" width="48" height="48"/> ID:<span>{{member.id}}</span> Name: <span>{{member.login}}</span> </p> </li> </ul> ` }) export class MembersComponent implements OnInit { members: Member[]; constructor(private memberService: MemberService) { } ngOnInit() { this.memberService.getMembers() .subscribe(data => { if (data) this.members = data; }); } }
import { Injectable } from '@angular/core'; import { Http } from '@angular/http'; @Injectable() export class MemberService { constructor(private http: Http) { } getMembers() { return this.http .get(`https://api.github.com/orgs/angular/members?page=1&per_page=5`) .map(res => res.json()) } }
本系列教程的主要目的是让初学者对 Angular 的相关基础知识,有必定的了解。除了本系列教程外,初学者还能够参考如下教程: