Angular X中使用ngrx的方法详解（附源码）

时间：2020-12-14 14:50:57|栏目：AngularJS|点击：次

前言

ngrx 是 Angular框架的状态容器，提供可预测化的状态管理。下面话不多说，来一起看看详细的介绍：

1.首先创建一个可路由访问的模块这里命名为：DemopetModule。

包括文件：demopet.html、demopet.scss、demopet.component.ts、demopet.routes.ts、demopet.module.ts

代码如下：

demopet.html

<!--暂时放一个标签-->
<h1>Demo</h1>

demopet.scss

h1{
 color:#d70029;
}

demopet.component.ts

import { Component} from '@angular/core';

@Component({
 selector: 'demo-pet',
 styleUrls: ['./demopet.scss'],
 templateUrl: './demopet.html'
})
export class DemoPetComponent {
 //nothing now...
}

demopet.routes.ts

import { DemoPetComponent } from './demopet.component';

export const routes = [
 {
 path: '', pathMatch: 'full', children: [
 { path: '', component: DemoPetComponent }
 ]
 }
];

demopet.module.ts

import { CommonModule } from '@angular/common';
import { FormsModule } from '@angular/forms';
import { NgModule } from '@angular/core';
import { RouterModule } from '@angular/router';
import { routes } from './demopet.routes';

@NgModule({
 declarations: [
 DemoPetComponent,
 ],
 imports: [
 CommonModule,
 FormsModule,
 RouterModule.forChild(routes)
 ],
 providers: [
 ]
})
export class DemoPetModule {


}

整体代码结构如下：

运行效果如下：只是为了学习方便，能够有个运行的模块

2.安装ngrx

npm install @ngrx/core --save

npm install @ngrx/store --save

npm install @ngrx/effects --save

@ngrx/store是一个旨在提高写性能的控制状态的容器

3.使用ngrx

首先了解下单向数据流形式

代码如下：

pet-tag.actions.ts

import { Injectable } from '@angular/core';
import { Action } from '@ngrx/store';

@Injectable()
export class PettagActions{
 static LOAD_DATA='Load Data';
 loadData():Action{
 return {
  type:PettagActions.LOAD_DATA
 };
 }

 static LOAD_DATA_SUCCESS='Load Data Success';
 loadDtaSuccess(data):Action{
 return {
  type:PettagActions.LOAD_DATA_SUCCESS,
  payload:data
 };
 }


 static LOAD_INFO='Load Info';
 loadInfo():Action{
 return {
  type:PettagActions.LOAD_INFO
 };
 }

 static LOAD_INFO_SUCCESS='Load Info Success';
 loadInfoSuccess(data):Action{
 return {
  type:PettagActions.LOAD_INFO_SUCCESS,
  payload:data
 };
 }
}

pet-tag.reducer.ts

import { Action } from '@ngrx/store';
import { Observable } from 'rxjs/Observable';
import { PettagActions } from '../action/pet-tag.actions';

export function petTagReducer(state:any,action:Action){
 switch(action.type){

 case PettagActions.LOAD_DATA_SUCCESS:{

  return action.payload;
 }

 // case PettagActions.LOAD_INFO_SUCCESS:{

 // return action.payload;
 // }

 default:{

  return state;
 }
 }
}

export function infoReducer(state:any,action:Action){
 switch(action.type){

 case PettagActions.LOAD_INFO_SUCCESS:{

  return action.payload;
 }

 default:{

  return state;
 }
 }
}

NOTE:Action中定义了我们期望状态如何发生改变 Reducer实现了状态具体如何改变

Action与Store之间添加ngrx/Effect 实现action异步请求与store处理结果间的解耦

pet-tag.effect.ts

import { Injectable } from '@angular/core';
import { Effect,Actions } from '@ngrx/effects';
import { PettagActions } from '../action/pet-tag.actions';
import { PettagService } from '../service/pet-tag.service';

@Injectable()
export class PettagEffect {

 constructor(
 private action$:Actions,
 private pettagAction:PettagActions,
 private service:PettagService
 ){}


 @Effect() loadData=this.action$
  .ofType(PettagActions.LOAD_DATA)
  .switchMap(()=>this.service.getData())
  .map(data=>this.pettagAction.loadDtaSuccess(data))

 
 @Effect() loadInfo=this.action$
  .ofType(PettagActions.LOAD_INFO)
  .switchMap(()=>this.service.getInfo())
  .map(data=>this.pettagAction.loadInfoSuccess(data));
}

4.修改demopet.module.ts 添加 ngrx支持

import { StoreModule } from '@ngrx/store';
import { EffectsModule } from '@ngrx/effects';
import { PettagActions } from './action/pet-tag.actions';
import { petTagReducer,infoReducer } from './reducer/pet-tag.reducer';
import { PettagEffect } from './effect/pet-tag.effect';

@NgModule({
 declarations: [
 DemoPetComponent,
 ],
 imports: [
 CommonModule,
 FormsModule,
 RouterModule.forChild(routes),
 //here new added
 StoreModule.provideStore({
 pet:petTagReducer,
 info:infoReducer
 }),
 EffectsModule.run(PettagEffect)
 ],
 providers: [
 PettagActions,
 PettagService
 ]
})
export class DemoPetModule { }

5.调用ngrx实现数据列表获取与单个详细信息获取

demopet.component.ts

import { Component, OnInit, ViewChild, AfterViewInit } from '@angular/core';
import { Observable } from "rxjs";
import { Store } from '@ngrx/store';
import { Subscription } from 'rxjs/Subscription';
import { HttpService } from '../shared/services/http/http.service';
import { PetTag } from './model/pet-tag.model';
import { PettagActions } from './action/pet-tag.actions';

@Component({
 selector: 'demo-pet',
 styleUrls: ['./demopet.scss'],
 templateUrl: './demopet.html'
})
export class DemoPetComponent {

 private sub: Subscription;
 public dataArr: any;
 public dataItem: any;
 public language: string = 'en';
 public param = {value: 'world'};

 constructor(
 private store: Store<PetTag>,
 private action: PettagActions
 ) {

 this.dataArr = store.select('pet');
 }

 ngOnInit() {

 this.store.dispatch(this.action.loadData());
 }

 ngOnDestroy() {

 this.sub.unsubscribe();
 }

 info() {

 console.log('info');
 this.dataItem = this.store.select('info');
 this.store.dispatch(this.action.loadInfo());
 }

}

demopet.html

<h1>Demo</h1>



<pre>
 <ul>
 <li *ngFor="let d of dataArr | async"> 
  DEMO : {{ d.msg }}
  <button (click)="info()">info</button>
 </li>
 </ul>

 {{ dataItem | async | json }}

 <h1 *ngFor="let d of dataItem | async"> {{ d.msg }} </h1>
</pre>

6.运行效果

初始化时候获取数据列表

点击info按钮获取详细详细

7.以上代码是从项目中取出的部分代码，其中涉及到HttpService需要自己封装，data.json demo.json两个测试用的json文件，名字随便取的当时。

http.service.ts

import { Inject, Injectable } from '@angular/core';
import { Http, Response, Headers, RequestOptions, URLSearchParams } from '@angular/http';
import { Observable } from "rxjs";
import 'rxjs/add/operator/map';
import 'rxjs/operator/delay';
import 'rxjs/operator/mergeMap';
import 'rxjs/operator/switchMap';
import 'rxjs/add/operator/catch';
import 'rxjs/add/observable/throw';
import { handleError } from './handleError';
import { rootPath } from './http.config';

@Injectable()
export class HttpService {

 private _root: string="";

 constructor(private http: Http) {

 this._root=rootPath;
 }

 public get(url: string, data: Map<string, any>, root: string = this._root): Observable<any> {
 if (root == null) root = this._root;
 
 let params = new URLSearchParams();
 if (!!data) {
  data.forEach(function (v, k) {
  params.set(k, v);
  });
 
 }
 return this.http.get(root + url, { search: params })
   .map((resp: Response) => resp.json())
   .catch(handleError);
 }



}

8.模块源代码

下载地址

总结

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