Angular 4 实例(第一部分)
Angular 4 实例
在这一章中,我们将学习几个Angular4的例子。
首先,我们创建一个输入用户名和密码的登录表单。输入正确的值后,它将输入内部并显示另一个表单,您可以在其中输入客户详细信息。此外,我们还创建了四个组件——页眉、页脚、用户登录和主页。
使用以下命令创建组件:
ng g component header C:\ngexamples\aexamples>ng g component header installing component create src\app\header\header.component.css create src\app\header\header.component.html create src\app\header\header.component.spec.ts create src\app\header\header.component.ts update src\app\app.module.ts ng g component footer C:\ngexamples\aexamples>ng g component footer installing component create src\app\footer\footer.component.css create src\app\footer\footer.component.html create src\app\footer\footer.component.spec.ts create src\app\footer\footer.component.ts update src\app\app.module.ts ng g component userlogin C:\ngexamples\aexamples>ng g component userlogin installing component create src\app\userlogin\userlogin.component.css create src\app\userlogin\userlogin.component.html create src\app\userlogin\userlogin.component.spec.ts create src\app\userlogin\userlogin.component.ts update src\app\app.module.ts ng g component mainpage C:\ngexamples\aexamples>ng g component mainpage installing component create src\app\mainpage\mainpage.component.css create src\app\mainpage\mainpage.component.html create src\app\mainpage\mainpage.component.spec.ts create src\app\mainpage\mainpage.component.ts update src\app\app.module.ts
在app.module.ts中,父模块在创建时添加了所有组件。该文件如下所示:
import { BrowserModule } from '@angular/platform-browser'; import { NgModule } from '@angular/core'; import { ReactiveFormsModule } from '@angular/forms'; import { RouterModule, Routes} froms '@angular/router'; import { BrowserAnimationsModule } from '@angular/platform-browser/animations'; import {MdTableModule} from '@angular/material'; import {HttpModule} from "@angular/http"; import {MdInputModule} from '@angular/material'; import { AppComponent } from './app.component'; import { HeaderComponent } from './header/header.component'; import { FooterComponent } from './footer/footer.component'; import { UserloginComponent } from './userlogin/userlogin.component'; import { MainpageComponent } from './mainpage/mainpage.component'; const appRoutes: Routes = [ { path: '', component: UserloginComponent }, { path: 'app-mainpage', component: MainpageComponent } ]; @NgModule({ declarations: [ AppComponent, HeaderComponent, FooterComponent, UserloginComponent, MainpageComponent ], imports: [ BrowserModule, ReactiveFormsModule, RouterModule.forRoot(appRoutes), BrowserAnimationsModule, HttpModule, MdTableModule, MdInputModule ], providers: [], bootstrap: [AppComponent] }) export class AppModule { }
添加上述创建的组件:
import { HeaderComponent } from './header/header.component'; import { FooterComponent } from './footer/footer.component'; import { UserloginComponent } from './userlogin/userlogin.component'; import { MainpageComponent } from './mainpage/mainpage.component';
组件也添加到声明中:
declarations: [ AppComponent, HeaderComponent, FooterComponent, UserloginComponent, MainpageComponent ],
在app.component.html,我们添加了用户将会看到的文件的主要结构。
<div class="mainpage"> <app-header></app-header> <router-outlet></router-outlet> <app-footer></app-footer> </div>
我们已经创建了div,并添加了<app-header></app-header>, <router-outlet></router-outlet>和<app-footer></app-footer>。
<router-outlet></router-outlet>用于页面之间的导航。这里,页面是登录表单,一旦成功,它将重定向到主页,即客户表单。
为了先获得登录表单,然后再获得mainpage.component.html,更改在app.module.ts中完成,如下所示。
import { BrowserModule } from '@angular/platform-browser'; import { NgModule } from '@angular/core'; import { ReactiveFormsModule } from '@angular/forms'; import { RouterModule, Routes} from '@angular/router'; import { BrowserAnimationsModule } from '@angular/platform-browser/animations'; import {MdTableModule} from '@angular/material'; import {HttpModule} from "@angular/http"; import {MdInputModule} from '@angular/material'; import { AppComponent } from './app.component'; import { HeaderComponent } from './header/header.component'; import { FooterComponent } from './footer/footer.component'; import { UserloginComponent } from './userlogin/userlogin.component'; import { MainpageComponent } from './mainpage/mainpage.component'; const appRoutes: Routes = [ { path: '', component: UserloginComponent }, { path: 'app-mainpage', component: MainpageComponent } ]; @NgModule({ declarations: [ AppComponent, HeaderComponent, FooterComponent, UserloginComponent, MainpageComponent ], imports: [ BrowserModule, ReactiveFormsModule, RouterModule.forRoot(appRoutes), BrowserAnimationsModule, HttpModule, MdTableModule, MdInputModule ], providers: [], bootstrap: [AppComponent] }) export class AppModule { }
我们已经从@anuglar/router导入RouterModule和Routes。在导入中,RouterModules采用appRoutes作为参数,上面定义为-
const appRoutes: Routes = [ { path: '', component: UserloginComponent }, { path: 'app-mainpage', component: MainpageComponent } ];
Routes采用组件数组,默认情况下调用UserLoginComponent。
在userlogin.component.ts中,我们已经导入了路由器,并根据如下所示的条件导航到mainpage.component.html
import { Component, OnInit } from '@angular/core'; import { FormGroup, FormControl, Validators} from '@angular/forms'; import { Router} from '@angular/router'; @Component({ selector: 'app-userlogin', templateUrl: './userlogin.component.html', styleUrls: ['./userlogin.component.css'] }) export class UserloginComponent implements OnInit { formdata; constructor(private router: Router) { } ngOnInit() { this.formdata = new FormGroup({ uname: new FormControl("", Validators.compose([ Validators.required, Validators.minLength(6) ])), passwd: new FormControl("", this.passwordvalidation) }); } passwordvalidation(formcontrol) { if (formcontrol.value.length < 5) { return {"passwd" : true}; } } onClickSubmit(data) { console.log(data.uname); if (data.uname=="systemadmin" && data.passwd=="admin123") { alert("Login Successful"); this.router.navigate(['app-mainpage']) } else { alert("Invalid Login"); return false; } } }
以下是app.component.ts文件的内容。其中仅显示默认的详细信息。
import { Component } from '@angular/core'; @Component({ selector: 'app-root', templateUrl: './app.component.html', styleUrls: ['./app.component.css'] }) export class AppComponent {title = 'app';}
现在让我们显示每个组件文件的详细信息。首先,我们将首先讨论header组件。对于新组件,创建四个文件:header.component.ts, header.component.html, header.component.css和header.component.spec.ts
header.component.ts
import { Component, OnInit } from '@angular/core'; @Component({ selector: 'app-header', templateUrl: './header.component.html', styleUrls: ['./header.component.css'] }) export class HeaderComponent implements OnInit { constructor() { } ngOnInit() {} }
header.component.html
<div> <hr /> </div>
我们没有添加任何CSS。这使得header.component.css文件为空。另外,header.compoent.spec.tsT文件是空的,因为这里不考虑测试用例。
对于header,我们将画一条水平线。可以添加徽标或任何其他细节,使标题看起来更有创意。
现在让我们考虑创建footer组件。
对于footer组件,需要创建footer.component.ts, footer.component.html, footer.component.spec.ts和footer.component.css。
footer.component.ts
import { Component, OnInit } from '@angular/core'; @Component({ selector: 'app-footer', templateUrl: './footer.component.html', styleUrls: ['./footer.component.css'] }) export class FooterComponent implements OnInit { constructor() { } ngOnInit() { } }
footer.component.html
<hr/>