前言
ngrx 是 Angular框架的狀態容器，提供可預測化的狀態管理。下面話不多說，來一起看看詳細的介紹：
1.首先創建一個可路由訪問的模塊 這里命名為：DemopetModule。
包括文件：demopet.html、demopet.scss、demopet.component.ts、demopet.routes.ts、demopet.module.ts
代碼如下：
demopet.html
<!--暫時放一個標簽--><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 {}整體代碼結構如下：
運行效果如下：只是為了學習方便，能夠有個運行的模塊
2.安裝ngrx
npm install @ngrx/core --savenpm install @ngrx/store --savenpm install @ngrx/effects --save
@ngrx/store是一個旨在提高寫性能的控制狀態的容器
3.使用ngrx
首先了解下單向數據流形式
代碼如下：
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中定義了我們期望狀態如何發生改變 Reducer實現了狀態具體如何改變
Action與Store之間添加ngrx/Effect 實現action異步請求與store處理結果間的解耦
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.調用ngrx實現數據列表獲取與單個詳細信息獲取
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.運行效果
初始化時候獲取數據列表
點擊info按鈕 獲取詳細詳細
7.以上代碼是從項目中取出的部分代碼，其中涉及到HttpService需要自己封裝，data.json demo.json兩個測試用的json文件，名字隨便取的當時。
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.模塊源代碼
總結
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