学习一个框架或库的最好方法是看官方文档,并着手去写例子。最近在利用空闲的时间学习angular,那今天就尝试写一个message组件,并通过message服务动态加载message组件。
我所参与的项目基本是用jquery完成的。之前,在项目中自己动手写过一个简单的message插件,样子如下图。

那现在就使用angular(版本5.0.0)来实现message组件。
message组件
message组件要根据传入的类型、消息和duration来显示。创建三个文件:message.component.ts,message.component.html,message.component.css,代码如下。
//message.component.ts
import {component,input,oninit,changedetectionstrategy} from '@angular/core';
import {
trigger,
state,
style,
transition,
animate
} from '@angular/animations';
const mapping={
success:'glyphicon-ok-sign',
warning:'glyphicon-exclamation-sign',
error:'glyphicon-exclamation-sign',
info:'glyphicon-ok-circle'
}
@component({
selector:'upc-ng-message',
templateurl:'./message.component.html',
styleurls:['./message.component.css'],
changedetection:changedetectionstrategy.onpush
})
export class messagecomponent implements oninit{
ngoninit(): void {
this.typeclass=['upc-message-' + this.msgtype];
this.typeiconclass=[mapping[this.msgtype]];
}
@input() msgtype:'success' | 'info' | 'warning' | 'error'='info'
@input() payload:string = ''
private typeclass
private typeiconclass
}
<!--*message.component.html-->
<div class="upc-message">
<div class="upc-message-content" [ngclass]="typeclass">
<i class="glyphicon" [ngclass]="typeiconclass"></i>
{{payload}}
</div>
</div>
.upc-message {
position: fixed;
z-index: 1999;
width: 100%;
top: 36px;
left: 0;
pointer-events: none;
padding: 8px;
text-align: center;
}
.upc-message i {
margin-right: 8px;
font-size: 14px;
top: 1px;
position: relative;
}
.upc-message-success i {
color: green;
}
.upc-message-warning i {
color: yellow;
}
.upc-message-error i {
color: red;
}
.upc-message-content {
padding: 8px 16px;
-ms-border-radius: 4px;
border-radius: 4px;
-webkit-box-shadow: 0 2px 8px #000000;
-ms-box-shadow: 0 2px 8px #000000;
box-shadow: 0 2px 8px #000000;
box-shadow: 0 2px 8px rgba(0,0,0,.2);
background: #fff;
display: inline-block;
pointer-events: all;
}
componentloader
通过官方文档一节,可以了解动态创建组件需要通过componentfactoryresolver来完成。使用componentfactoryresolver创建componentfactory,再通过componentfactory的create方法创建组件。看官方文档中api的说明,componentfactory的create方法至少需要一个injector参数,而injector的创建在文档中也有提到,其中参数providers为需要注入的类。再梳理下整个过程:
- 提供providers
- 创建injector实例
- 创建componetfactory
- 使用componetfactory创建componentref
//componentfactory的create方法 create(injector: injector, projectablenodes?: any[][], rootselectorornode?: string|any, ngmodule?: ngmoduleref<any>): componentref<c> //使用injector的create创建injector实例 static create(providers: staticprovider[], parent?: injector): injector
为了代码的复用,这里创建通用的loader类来完成组件的动态创建。其中,attch方法用于初始化componetfactory(参数为组件类型);to方法用于标识组件的父容器;provider方法用于初始化可注入的类;create方法用于创建组件并手动变更检测;remove方法用于移除组件。
import {
componentfactoryresolver,
componentfactory,
componentref,
type,
injector,
provider,
elementref
} from '@angular/core';
export class componentloader<t>{
constructor(private _cfr: componentfactoryresolver,
private _injector: injector) {
}
private _componentfactory: componentfactory<t>
attch(componenttype: type<t>): componentloader<t> {
this._componentfactory = this._cfr.resolvecomponentfactory<t>(componenttype);
return this;
}
private _parent: element
to(parent: string | elementref): componentloader<t> {
if (parent instanceof elementref) {
this._parent = parent.nativeelement;
} else {
this._parent = document.queryselector(parent);
}
return this;
}
private _providers: provider[] = [];
provider(provider: provider) {
this._providers.push(provider);
}
create(opts: {}): componentref<t> {
const injector = injector.create(this._providers as any[], this._injector);
const componentref = this._componentfactory.create(injector);
object.assign(componentref.instance, opts);
if (this._parent) {
this._parent.appendchild(componentref.location.nativeelement);
}
componentref.changedetectorref.markforcheck();
componentref.changedetectorref.detectchanges();
return componentref;
}
remove(ref:componentref<t>){
if(this._parent){
this._parent.removechild(ref.location.nativeelement)
}
ref=null;
}
}
同时,为了便于loader的创建,再创建loaderfactory类,代码如下:
import {
componentfactoryresolver,
injector,
injectable,
elementref
} from '@angular/core';
import { componentloader } from './component-loader.class';
@injectable()
export class componentloaderfactory {
constructor(private _injector: injector,
private _cfr: componentfactoryresolver) {
}
create<t>(): componentloader<t> {
return new componentloader(this._cfr, this._injector);
}
}
message service
message service提供显示message的api,代码如下:
import {injectable,injector} from '@angular/core';
import { componentloaderfactory } from '../component-loader/component-loader.factory';
import {messagecomponent} from './message.component';
import {componentloader} from '../component-loader/component-loader.class';
@injectable()
export class messageservice{
constructor(private _clf:componentloaderfactory,private _injector:injector){
this.loader=this._clf.create<messagecomponent>();
}
private loader:componentloader<messagecomponent>
private createmessage(t,c,duration=2000){
this.loader.attch(messagecomponent).to('body');
const opts = {
msgtype: t,
payload:c
};
const ref = this.loader.create(opts);
ref.changedetectorref.markforcheck();
ref.changedetectorref.detectchanges();
let self=this;
let st = settimeout(() => {
self.loader.remove(ref);
}, duration);
}
public info(payload,duration?) {
this.createmessage('info',payload,duration);
}
public success(payload,duration?) {
this.createmessage('success',payload,duration);
}
public error(payload,duration?) {
this.createmessage('error',payload,duration);
}
public warning(payload,duration?) {
this.createmessage('warning',payload,duration);
}
}
message.module
最后,增加message.module.ts。记得要把动态创建的组件添加到entrycomponents数组中。
import {ngmodule} from '@angular/core';
import { commonmodule } from '@angular/common';
import {messagecomponent} from './message.component';
import {messageservice} from './message.service';
import {componentloaderfactory} from '../component-loader/component-loader.factory';
@ngmodule({
imports:[commonmodule],
declarations:[messagecomponent],
providers:[messageservice,componentloaderfactory],
entrycomponents:[messagecomponent],
exports:[messagecomponent]
})
export class messagemodule{
}
使用方法
注入messageservice,调用api使用message组件。
this._msgservice.success('成功了!');
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。
蒋金龙39235736