使用TypeScript创建单页天气查询应用程序
之前简单介绍了TypeScript，认识Typescript，对其有了一个初步的认识，本系列主要以实践为主，基本语法不做介绍。本文将使用TypeScript创建单页应用程序（SPA）示例，天气查询。
准备工作
要完成示例项目，需要在安装 Node.js 和 Angular CLI（一个用于 Angular 的命令行接口）：
安装 Node.js：
- [下载nodejs]适合的版本，选择默认选项来完成安装。
- 命令行运行
node -v来验证版本号，当前最新版本为 v10.13.0。
安装 Angular CLI：
- 运行
npm install -g angular-cli进行安装 - 成功完成安装后，命令行运行
ng -v，查看 CLI 版本号
创建基础应用程序和模块
创建一个 Angular 项目
运行下面的命令来生成一个新 Angular 项目（其中 quintion-ng-app 是项目名称）：
ng new quintion-ng-app --skip-git
安装所有需要的包和 Angular 基础应用程序，项目结构如下：
qzcloud-ng-app/src 目录的内容包括：
运行应用程序:
ng serve
默认情况下，进程在端口 4200 上启动。可以运行 ng serve --port 4206 命令来指定运行端口号。
打开浏览器并输入http://localhost:4206/。运行结果如图，这表明应用程序已启动、运行并准备就绪。对项目代码的任何修改都将自动重新启动项目。
将模块组件代码
在片段1中，第 16 行显示了 AppModule 模块的声明。
片段1：src/app/app.module.ts：
此处代码为项目创建时自动生成的。
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
@NgModule({
declarations: [
AppComponent
],
imports: [
BrowserModule,
AppRoutingModule
],
providers: [],
bootstrap: [AppComponent] //启动组件
})
export class AppModule { }
此模块仅包含一个组件AppComponent
组件内部结构
片段2为 src/app/app.component.ts 文件中的主要应用程序组件的内容。
import { Component } from '@angular/core';
@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.scss']
})
export class AppComponent {
title = 'quintion-ng-app';
}
这是 app.component.html 文件中的主要应用程序组件的内容：
<style>
:host {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
font-size: 14px;
color: #333;
box-sizing: border-box;
-webkit-font-smoothing: antialiased;
-moz-osx-font-smoothing: grayscale;
}
h1,
h2,
h3,
h4,
h5,
h6 {
margin: 8px 0;
}
p {
margin: 0;
}
.spacer {
flex: 1;
}
.toolbar {
position: absolute;
top: 0;
left: 0;
right: 0;
height: 60px;
display: flex;
align-items: center;
background-color: #1976d2;
color: white;
font-weight: 600;
}
.toolbar img {
margin: 0 16px;
}
.toolbar #twitter-logo {
height: 40px;
margin: 0 16px;
}
.toolbar #twitter-logo:hover {
opacity: 0.8;
}
.content {
display: flex;
margin: 82px auto 32px;
padding: 0 16px;
max-width: 960px;
flex-direction: column;
align-items: center;
}
svg.material-icons {
height: 24px;
width: auto;
}
svg.material-icons:not(:last-child) {
margin-right: 8px;
}
.card svg.material-icons path {
fill: #888;
}
.card-container {
display: flex;
flex-wrap: wrap;
justify-content: center;
margin-top: 16px;
}
.card {
border-radius: 4px;
border: 1px solid #eee;
background-color: #fafafa;
height: 40px;
width: 200px;
margin: 0 8px 16px;
padding: 16px;
display: flex;
flex-direction: row;
justify-content: center;
align-items: center;
transition: all 0.2s ease-in-out;
line-height: 24px;
}
.card-container .card:not(:last-child) {
margin-right: 0;
}
.card.card-small {
height: 16px;
width: 168px;
}
.card-container .card:not(.highlight-card) {
cursor: pointer;
}
.card-container .card:not(.highlight-card):hover {
transform: translateY(-3px);
box-shadow: 0 4px 17px rgba(0, 0, 0, 0.35);
}
.card-container .card:not(.highlight-card):hover .material-icons path {
fill: rgb(105, 103, 103);
}
.card.highlight-card {
background-color: #1976d2;
color: white;
font-weight: 600;
border: none;
width: auto;
min-width: 30%;
position: relative;
}
.card.card.highlight-card span {
margin-left: 60px;
}
svg#rocket {
width: 80px;
position: absolute;
left: -10px;
top: -24px;
}
svg#rocket-smoke {
height: calc(100vh - 95px);
position: absolute;
top: 10px;
right: 180px;
z-index: -10;
}
a,
a:visited,
a:hover {
color: #1976d2;
text-decoration: none;
}
a:hover {
color: #125699;
}
.terminal {
position: relative;
width: 80%;
max-width: 600px;
border-radius: 6px;
padding-top: 45px;
margin-top: 8px;
overflow: hidden;
background-color: rgb(15, 15, 16);
}
.terminal::before {
content: "2022 2022 2022";
position: absolute;
top: 0;
left: 0;
height: 4px;
background: rgb(58, 58, 58);
color: #c2c3c4;
width: 100%;
font-size: 2rem;
line-height: 0;
padding: 14px 0;
text-indent: 4px;
}
.terminal pre {
font-family: SFMono-Regular,Consolas,Liberation Mono,Menlo,monospace;
color: white;
padding: 0 1rem 1rem;
margin: 0;
}
.circle-link {
height: 40px;
width: 40px;
border-radius: 40px;
margin: 8px;
background-color: white;
border: 1px solid #eeeeee;
display: flex;
justify-content: center;
align-items: center;
cursor: pointer;
box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
transition: 1s ease-out;
}
.circle-link:hover {
transform: translateY(-0.25rem);
box-shadow: 0px 3px 15px rgba(0, 0, 0, 0.2);
}
footer {
margin-top: 8px;
display: flex;
align-items: center;
line-height: 20px;
}
footer a {
display: flex;
align-items: center;
}
.github-star-badge {
color: #24292e;
display: flex;
align-items: center;
font-size: 12px;
padding: 3px 10px;
border: 1px solid rgba(27,31,35,.2);
border-radius: 3px;
background-image: linear-gradient(-180deg,#fafbfc,#eff3f6 90%);
margin-left: 4px;
font-weight: 600;
font-family: -apple-system,BlinkMacSystemFont,Segoe UI,Helvetica,Arial,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol;
}
.github-star-badge:hover {
background-image: linear-gradient(-180deg,#f0f3f6,#e6ebf1 90%);
border-color: rgba(27,31,35,.35);
background-position: -.5em;
}
.github-star-badge .material-icons {
height: 16px;
width: 16px;
margin-right: 4px;
}
svg#clouds {
position: fixed;
bottom: -160px;
left: -230px;
z-index: -10;
width: 1920px;
}
/* Responsive Styles */
@media screen and (max-width: 767px) {
.card-container > *:not(.circle-link) ,
.terminal {
width: 100%;
}
.card:not(.highlight-card) {
height: 16px;
margin: 8px 0;
}
.card.highlight-card span {
margin-left: 72px;
}
svg#rocket-smoke {
right: 120px;
transform: rotate(-5deg);
}
}
@media screen and (max-width: 575px) {
svg#rocket-smoke {
display: none;
visibility: hidden;
}
}
</style>
<div class="toolbar" role="banner">
<img
width="40"
alt="Angular Logo"
src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHZpZXdCb3g9IjAgMCAyNTAgMjUwIj4KICAgIDxwYXRoIGZpbGw9IiNERDAwMzEiIGQ9Ik0xMjUgMzBMMzEuOSA2My4ybDE0LjIgMTIzLjFMMTI1IDIzMGw3OC45LTQzLjcgMTQuMi0xMjMuMXoiIC8+CiAgICA8cGF0aCBmaWxsPSIjQzMwMDJGIiBkPSJNMTI1IDMwdjIyLjItLjFWMjMwbDc4LjktNDMuNyAxNC4yLTEyMy4xTDEyNSAzMHoiIC8+CiAgICA8cGF0aCAgZmlsbD0iI0ZGRkZGRiIgZD0iTTEyNSA1Mi4xTDY2LjggMTgyLjZoMjEuN2wxMS43LTI5LjJoNDkuNGwxMS43IDI5LjJIMTgzTDEyNSA1Mi4xem0xNyA4My4zaC0zNGwxNy00MC45IDE3IDQwLjl6IiAvPgogIDwvc3ZnPg=="
/>
<span>Welcome</span>
<div class="spacer"></div>
<a aria-label="Angular on twitter" target="_blank" rel="noopener" href="https://twitter.com/angular" title="Twitter">
<svg id="twitter-logo" height="24" data-name="Logo" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 400 400">
<rect width="400" height="400" fill="none"/>
<path d="M153.62,301.59c94.34,0,145.94-78.16,145.94-145.94,0-2.22,0-4.43-.15-6.63A104.36,104.36,0,0,0,325,122.47a102.38,102.38,0,0,1-29.46,8.07,51.47,51.47,0,0,0,22.55-28.37,102.79,102.79,0,0,1-32.57,12.45,51.34,51.34,0,0,0-87.41,46.78A145.62,145.62,0,0,1,92.4,107.81a51.33,51.33,0,0,0,15.88,68.47A50.91,50.91,0,0,1,85,169.86c0,.21,0,.43,0,.65a51.31,51.31,0,0,0,41.15,50.28,51.21,51.21,0,0,1-23.16.88,51.35,51.35,0,0,0,47.92,35.62,102.92,102.92,0,0,1-63.7,22A104.41,104.41,0,0,1,75,278.55a145.21,145.21,0,0,0,78.62,23" fill="#fff"/>
</svg>
</a>
</div>
<div class="content" role="main">
<div class="card highlight-card card-small">
<svg id="rocket" alt="Rocket Ship" xmlns="http://www.w3.org/2000/svg" width="101.678" height="101.678" viewBox="0 0 101.678 101.678">
<g id="Group_83" data-name="Group 83" transform="translate(-141 -696)">
<circle id="Ellipse_8" data-name="Ellipse 8" cx="50.839" cy="50.839" r="50.839" transform="translate(141 696)" fill="#dd0031"/>
<g id="Group_47" data-name="Group 47" transform="translate(165.185 720.185)">
<path id="Path_33" data-name="Path 33" d="M3.4,42.615a3.084,3.084,0,0,0,3.553,3.553,21.419,21.419,0,0,0,12.215-6.107L9.511,30.4A21.419,21.419,0,0,0,3.4,42.615Z" transform="translate(0.371 3.363)" fill="#fff"/>
<path id="Path_34" data-name="Path 34" d="M53.3,3.221A3.09,3.09,0,0,0,50.081,0,48.227,48.227,0,0,0,18.322,13.437c-6-1.666-14.991-1.221-18.322,7.218A33.892,33.892,0,0,1,9.439,25.1l-.333.666a3.013,3.013,0,0,0,.555,3.553L23.985,43.641a2.9,2.9,0,0,0,3.553.555l.666-.333A33.892,33.892,0,0,1,32.647,53.3c8.55-3.664,8.884-12.326,7.218-18.322A48.227,48.227,0,0,0,53.3,3.221ZM34.424,9.772a6.439,6.439,0,1,1,9.106,9.106,6.368,6.368,0,0,1-9.106,0A6.467,6.467,0,0,1,34.424,9.772Z" transform="translate(0 0.005)" fill="#fff"/>
</g>
</g>
</svg>
<span>{{ title }} app is running!</span>
<svg id="rocket-smoke" alt="Rocket Ship Smoke" xmlns="http://www.w3.org/2000/svg" width="516.119" height="1083.632" viewBox="0 0 516.119 1083.632">
<path id="Path_40" data-name="Path 40" d="M644.6,141S143.02,215.537,147.049,870.207s342.774,201.755,342.774,201.755S404.659,847.213,388.815,762.2c-27.116-145.51-11.551-384.124,271.9-609.1C671.15,139.365,644.6,141,644.6,141Z" transform="translate(-147.025 -140.939)" fill="#f5f5f5"/>
</svg>
</div>
<h2>Resources</h2>
<p>Here are some links to help you get started:</p>
<div class="card-container">
<a class="card" target="_blank" rel="noopener" href="https://angular.io/tutorial">
<svg class="material-icons" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M5 13.18v4L12 21l7-3.82v-4L12 17l-7-3.82zM12 3L1 9l11 6 9-4.91V17h2V9L12 3z"/></svg>
<span>Learn Angular</span>
<svg class="material-icons" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M10 6L8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg> </a>
<a class="card" target="_blank" rel="noopener" href="https://angular.io/cli">
<svg class="material-icons" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M9.4 16.6L4.8 12l4.6-4.6L8 6l-6 6 6 6 1.4-1.4zm5.2 0l4.6-4.6-4.6-4.6L16 6l6 6-6 6-1.4-1.4z"/></svg>
<span>CLI Documentation</span>
<svg class="material-icons" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M10 6L8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg>
</a>
<a class="card" target="_blank" rel="noopener" href="https://blog.angular.io/">
<svg class="material-icons" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M13.5.67s.74 2.65.74 4.8c0 2.06-1.35 3.73-3.41 3.73-2.07 0-3.63-1.67-3.63-3.73l.03-.36C5.21 7.51 4 10.62 4 14c0 4.42 3.58 8 8 8s8-3.58 8-8C20 8.61 17.41 3.8 13.5.67zM11.71 19c-1.78 0-3.22-1.4-3.22-3.14 0-1.62 1.05-2.76 2.81-3.12 1.77-.36 3.6-1.21 4.62-2.58.39 1.29.59 2.65.59 4.04 0 2.65-2.15 4.8-4.8 4.8z"/></svg>
<span>Angular Blog</span>
<svg class="material-icons" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M10 6L8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg>
</a>
</div>
<h2>Next Steps</h2>
<p>What do you want to do next with your app?</p>
<input type="hidden" #selection>
<div class="card-container">
<div class="card card-small" (click)="selection.value = 'component'" tabindex="0">
<svg class="material-icons" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M19 13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z"/></svg>
<span>New Component</span>
</div>
<div class="card card-small" (click)="selection.value = 'material'" tabindex="0">
<svg class="material-icons" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M19 13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z"/></svg>
<span>Angular Material</span>
</div>
<div class="card card-small" (click)="selection.value = 'pwa'" tabindex="0">
<svg class="material-icons" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M19 13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z"/></svg>
<span>Add PWA Support</span>
</div>
<div class="card card-small" (click)="selection.value = 'dependency'" tabindex="0">
<svg class="material-icons" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M19 13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z"/></svg>
<span>Add Dependency</span>
</div>
<div class="card card-small" (click)="selection.value = 'test'" tabindex="0">
<svg class="material-icons" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M19 13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z"/></svg>
<span>Run and Watch Tests</span>
</div>
<div class="card card-small" (click)="selection.value = 'build'" tabindex="0">
<svg class="material-icons" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M19 13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z"/></svg>
<span>Build for Production</span>
</div>
</div>
<div class="terminal" [ngSwitch]="selection.value">
<pre *ngSwitchDefault>ng generate component xyz</pre>
<pre *ngSwitchCase="'material'">ng add @angular/material</pre>
<pre *ngSwitchCase="'pwa'">ng add @angular/pwa</pre>
<pre *ngSwitchCase="'dependency'">ng add _____</pre>
<pre *ngSwitchCase="'test'">ng test</pre>
<pre *ngSwitchCase="'build'">ng build --prod</pre>
</div>
<div class="card-container">
<a class="circle-link" title="Animations" href="https://angular.io/guide/animations" target="_blank" rel="noopener">
<svg id="Group_20" data-name="Group 20" xmlns="http://www.w3.org/2000/svg" width="21.813" height="23.453" viewBox="0 0 21.813 23.453">
<path id="Path_15" data-name="Path 15" d="M4099.584,972.736h0l-10.882,3.9,1.637,14.4,9.245,5.153,9.245-5.153,1.686-14.4Z" transform="translate(-4088.702 -972.736)" fill="#ffa726"/>
<path id="Path_16" data-name="Path 16" d="M4181.516,972.736v23.453l9.245-5.153,1.686-14.4Z" transform="translate(-4170.633 -972.736)" fill="#fb8c00"/>
<path id="Path_17" data-name="Path 17" d="M4137.529,1076.127l-7.7-3.723,4.417-2.721,7.753,3.723Z" transform="translate(-4125.003 -1058.315)" fill="#ffe0b2"/>
<path id="Path_18" data-name="Path 18" d="M4137.529,1051.705l-7.7-3.723,4.417-2.721,7.753,3.723Z" transform="translate(-4125.003 -1036.757)" fill="#fff3e0"/>
<path id="Path_19" data-name="Path 19" d="M4137.529,1027.283l-7.7-3.723,4.417-2.721,7.753,3.723Z" transform="translate(-4125.003 -1015.199)" fill="#fff"/>
</svg>
</a>
<a class="circle-link" title="CLI" href="https://cli.angular.io/" target="_blank" rel="noopener">
<svg alt="Angular CLI Logo" xmlns="http://www.w3.org/2000/svg" width="21.762" height="23.447" viewBox="0 0 21.762 23.447">
<g id="Group_21" data-name="Group 21" transform="translate(0)">
<path id="Path_20" data-name="Path 20" d="M2660.313,313.618h0l-10.833,3.9,1.637,14.4,9.2,5.152,9.244-5.152,1.685-14.4Z" transform="translate(-2649.48 -313.618)" fill="#37474f"/>
<path id="Path_21" data-name="Path 21" d="M2741.883,313.618v23.447l9.244-5.152,1.685-14.4Z" transform="translate(-2731.05 -313.618)" fill="#263238"/>
<path id="Path_22" data-name="Path 22" d="M2692.293,379.169h11.724V368.618h-11.724Zm11.159-.6h-10.608v-9.345h10.621v9.345Z" transform="translate(-2687.274 -362.17)" fill="#fff"/>
<path id="Path_23" data-name="Path 23" d="M2709.331,393.688l.4.416,2.265-2.28-2.294-2.294-.4.4,1.893,1.893Z" transform="translate(-2702.289 -380.631)" fill="#fff"/>
<rect id="Rectangle_12" data-name="Rectangle 12" width="3.517" height="0.469" transform="translate(9.709 13.744)" fill="#fff"/>
</g>
</svg>
</a>
<a class="circle-link" title="Augury" href="https://augury.rangle.io/" target="_blank" rel="noopener">
<svg alt="Angular Augury Logo" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="21.81" height="23.447" viewBox="0 0 21.81 23.447">
<defs>
<clipPath id="clip-path">
<rect id="Rectangle_13" data-name="Rectangle 13" width="10.338" height="10.27" fill="none"/>
</clipPath>
</defs>
<g id="Group_25" data-name="Group 25" transform="translate(0)">
<path id="Path_24" data-name="Path 24" d="M3780.155,311.417h0l-10.881,3.9,1.637,14.4,9.244,5.152,9.244-5.152,1.685-14.4Z" transform="translate(-3769.274 -311.417)" fill="#4a3493"/>
<path id="Path_25" data-name="Path 25" d="M3862.088,311.417v23.447l9.244-5.152,1.685-14.4Z" transform="translate(-3851.207 -311.417)" fill="#311b92"/>
<g id="Group_24" data-name="Group 24" transform="translate(6.194 6.73)" opacity="0.5">
<g id="Group_23" data-name="Group 23" transform="translate(0 0)">
<g id="Group_22" data-name="Group 22" clip-path="url(#clip-path)">
<path id="Path_26" data-name="Path 26" d="M3832.4,373.252a5.168,5.168,0,1,1-5.828-4.383,5.216,5.216,0,0,1,2.574.3,3.017,3.017,0,1,0,3.252,4.086Z" transform="translate(-3822.107 -368.821)" fill="#fff"/>
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<router-outlet></router-outlet>元数据
使用 @Component 修饰器附加元数据，接受一个必需的配置对象，该对象包含 Angular 创建和呈现该组件和它的视图所需的信息。
片段2中的代码使用 @Component 配置了 3 个选项：
selector：一个 CSS 选择器，告诉 Angular 在父 HTML 文件中找到 selector 标记的地方创建和插入此组件的一个实例templateUrl：组件的 HTML 文件styleUrls：组件的样式表，比如.scss文件
组件模板位置
模板是一个 HTML 文件，用于告诉 Angular 如何呈现组件。在 片段2 的templateUrl属性，指向一个名为 app.component.html 的视图。
组件内的数据绑定
数据绑定用于告诉 Angular 如何呈现组件。在 app.component.ts 文件中，title 的值在类内设置，在 app.component.html 文件中使用。数据绑定可以是单向或双向的。在本例中，如果在双花括号 {{ }} 内提及该变量，则该映射是单向的。值从类传递到 HTML 文件。
自定义组件和路由
基础应用程序有一个模块、一个组件、一个类、一个模板、元数据和数据绑定 — 但它仍缺少 4 个其他的重要部分：
- 多个组件
- 路由
- 服务
- 微服务的使用
接下来，将创建这些自定义组件。运行以下命令：
ng generate component Menu：在 AppModule 根模块（同一个文件夹中）内创建 Menu 组件。ng generate component Weather：在 AppModule 根模块内名为 weather 的子文件夹中创建 Weather 组件。
执行完后将在app.module.ts中添加4个组件的内容：
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
//新添加的4个组件
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { MenuComponent } from './menu.component';
import { WeatherComponent } from './weather/weather.component';
@NgModule({
declarations: [
AppComponent,
MenuComponent,
WeatherComponent
],
imports: [
BrowserModule,
AppRoutingModule
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
创建路由
要让 Angular 能在组件之间导航，需要创建路由。使用片段3的内容覆盖menu.component.html 文件，以便 HTML 包含所有组件的正确菜单。
片段3：src/app/menu.component.html
<div class="row">
<div class="col-xs-12">
<ul class="nav nav-pills">
<li routerLinkActive="active"> <a [routerLink]="['/weather']">天气预报</a></li>
</ul>
</div>
</div>接下来，将 URL 路径映射到组件。在根模块的文件夹中，创建 src/app/app-routing.module.ts 的配置文件，配置如下。
import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';
import { WeatherComponent } from "./weather/weather.component";
const routes: Routes = [
{ path: "", redirectTo: "/weather", pathMatch: "full" },
{ path: "weather", component: WeatherComponent }
];
@NgModule({
imports: [RouterModule.forRoot(routes)],
exports: [RouterModule]
})
export class AppRoutingModule { }
修改 app.component.html内容，代码如下：
<div class="container">
<app-menu></app-menu>
<hr>
<router-outlet></router-outlet>
</div>
在 app.module.ts 文件中添加路由信息，如下：
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { MenuComponent } from './menu.component';
import { WeatherComponent } from './weather/weather.component';
@NgModule({
declarations: [
AppComponent,
MenuComponent,
WeatherComponent
],
imports: [
BrowserModule,
AppRoutingModule
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
再次运行应用程序：ng serve，运行结果如下：
创建服务
运行以下命令创建服务
ng generate service Shared 添加接口查询服务，代码如下：
import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { throwError as observableThrowError } from 'rxjs';
import { catchError, tap } from 'rxjs/operators';
@Injectable({
providedIn: 'root'
})
export class SharedService {
weatherURL1 = "https://www.tianqiapi.com/api/?version=v61&appid=45999158&appsecret=WL6GeLkx&cityid=";
weatherURL2 = "&city=";
totReqsMade: number = 0;
constructor(private _http: HttpClient) {
}
findWeather(cityid, city) {
this.totReqsMade = this.totReqsMade + 1;
return this._http
.get(this.weatherURL1 + cityid + this.weatherURL2 + city)
.pipe(
tap((response:any) => response),
catchError(this.handleError)
)
}
private handleError(error: any) {
return observableThrowError(error.error || 'Server error');
}
}@Injectable()：表明此 service 可注入到其他组件中totReqsMade：变量在这里声明，用于在 3 个组件之间传递它的值。将跟踪为获得微服务结果而发出的服务请求总数。- 定义了方法：findWeather()
将 weather.component.ts 替换如下代码：
import { Component, OnInit } from '@angular/core';
import { SharedService } from "./../shared.service";
@Component({
selector: 'app-weather',
templateUrl: './weather.component.html',
styleUrls: ['./weather.component.scss']
})
export class WeatherComponent implements OnInit {
cityid: string = "101280601";
city: string = "深圳";
op_city: string = "";
op_region: string = "";
op_country: string = "";
op_data: string = "";
op_today: string = "";
constructor(public _sharedService: SharedService) {}
ngOnInit() {}
callWeatherService() {
this._sharedService.findWeather(this.cityid, this.city).subscribe(
lstresult => {
this.op_city = lstresult["city"];
this.op_country = lstresult["country"];
this.op_data = lstresult;
this.op_today = [lstresult["wea"],[lstresult["tem2"],"-",lstresult["tem1"],"℃"].join("")].join(" ");
},
error => {
console.log("Error. The findWeather result JSON value is as follows:");
console.log(error);
}
);
}
}更新 app.module.ts 文件，加入这些服务：
import { BrowserModule } from "@angular/platform-browser";
import { NgModule } from "@angular/core";
import { FormsModule } from "@angular/forms";
import { HttpModule } from "@angular/http";
import { AppComponent } from "./app.component";
import { MenuComponent } from "./menu.component";
import { WeatherComponent } from "./weather/weather.component";
import { CONST_ROUTING } from "./app.routing";
import { SharedService } from "./shared.service";
@NgModule({
declarations: [AppComponent, MenuComponent, WeatherComponent, CurrencyComponent, MovieComponent],
imports: [BrowserModule, FormsModule, HttpModule, CONST_ROUTING],
providers: [SharedService],
bootstrap: [AppComponent]
})
export class AppModule {}组件视图
现在外面需要修改 HTML 文件，加入这些服务的调用。
weather.component.html
天气预报
城市： {{ this.op_city }} {{ this.op_country }}
天气： {{ this.op_today }}
天气服务请求次数： {{this._sharedService.totReqsMade}}
运行应用程序
运行应用程序，按照默认值执行查询深圳天气
功能实现了，接下来就优化ui，这里我们引入bootstrap，在根目录的index.html文件添加样式文件：
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
瞬间就变得美观了！
