如何在AngularX 中 使用ngrx

ngrx 是 Angular框架的状态容器，提供可预测化的状态管理。

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

9.我的微信公众号。