如何使用angular5 material2从api填充数据？

Question

Below I have added my 'table.component.html' and 'table.component.ts'. I am getting data from an API. I want to populate this data in the data table.

Below I have added my object, which I am recieving from the API)

[
  {position: 1, name: 'Hydrogen', weight: 1.0079, symbol: 'H'},
  {position: 2, name: 'Helium', weight: 4.0026, symbol: 'He'},
  {position: 3, name: 'Lithium', weight: 6.941, symbol: 'Li'},
  {position: 4, name: 'Beryllium', weight: 9.0122, symbol: 'Be'},
  {position: 5, name: 'Boron', weight: 10.811, symbol: 'B'},
];

Right now I hard coded the objects above but I want to populate the data from the API.

import {MediaMatcher} from '@angular/cdk/layout';
import { Component, OnInit, ViewEncapsulation,ViewChild,ChangeDetectorRef,Inject} from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { ActivatedRoute, Router } from '@angular/router';
import {MatPaginator, MatSort, MatTableDataSource,MatDialog, MatDialogRef, MAT_DIALOG_DATA} from '@angular/material';

@Component({

  selector: 'app-table',

  templateUrl: './table.component.html',

  styleUrls: ['./table.component.css']

})



export class TableComponent {

  displayedColumns = ['position', 'name', 'weight', 'symbol'];

  dataSource = new MatTableDataSource<Element>(ELEMENT_DATA);

   items: any;

  @ViewChild(MatPaginator) paginator: MatPaginator;
  constructor(private router: Router, private route: ActivatedRoute, private http: HttpClient,public dialog: MatDialog) { }
  ngOnInit() {

    this.http.get('/item').subscribe(data => {

      console.log("data>>>>>",data);

      this.items = data;

    });

  }

  ngAfterViewInit() {

    this.dataSource.paginator = this.paginator;

  }

}



export interface Element {

  name: string;

  position: number;

  weight: number;

  symbol: string;

}



const ELEMENT_DATA: Element[] = [
  {position: 1, name: 'Hydrogen', weight: 1.0079, symbol: 'H'},
  {position: 2, name: 'Helium', weight: 4.0026, symbol: 'He'},
  {position: 3, name: 'Lithium', weight: 6.941, symbol: 'Li'},
  {position: 4, name: 'Beryllium', weight: 9.0122, symbol: 'Be'},
  {position: 5, name: 'Boron', weight: 10.811, symbol: 'B'},
];

My HTML:

<div class="example-container mat-elevation-z8">

  <mat-table #table [dataSource]="dataSource">



    <!-- Position Column -->

    <ng-container matColumnDef="position">

      <mat-header-cell *matHeaderCellDef> No. </mat-header-cell>

      <mat-cell *matCellDef="let element"> {{element.position}} </mat-cell>

    </ng-container>



    <!-- Name Column -->

    <ng-container matColumnDef="name">

      <mat-header-cell *matHeaderCellDef> Name </mat-header-cell>

      <mat-cell *matCellDef="let element"> {{element.name}} </mat-cell>

    </ng-container>



    <!-- Weight Column -->

    <ng-container matColumnDef="weight">

      <mat-header-cell *matHeaderCellDef> Weight </mat-header-cell>

      <mat-cell *matCellDef="let element"> {{element.weight}} </mat-cell>

    </ng-container>



    <!-- Symbol Column -->

    <ng-container matColumnDef="symbol">

      <mat-header-cell *matHeaderCellDef> Symbol </mat-header-cell>

      <mat-cell *matCellDef="let element"> {{element.symbol}} </mat-cell>

    </ng-container>



    <mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>

    <mat-row *matRowDef="let row; columns: displayedColumns;"></mat-row>

  </mat-table>



  <mat-paginator #paginator

                 [pageSize]="10"

                 [pageSizeOptions]="[5, 10, 20]">

  </mat-paginator>

</div>

Answer 1

You need to pass the new data you get from the backend, to the dataSource that will be loaded to the table.

in your component change this:

dataSource = new MatTableDataSource<Element>(ELEMENT_DATA);

to:

dataSource = new MatTableDataSource<Element>();

Then you need to enter the new data into it (assuming your data has the same format as the hard coded one, position, name , weight and symbol):

ngOnInit() {

    this.http.get('/item').subscribe(data => {

      console.log("data>>>>>",data);

      this.items = data;

      this.dataSource.data = this.itens;
    });

  }

Answer 2

I would recommend that you take a look into the $http Angular documentation ( https://docs.angularjs.org/api/ng/service/ $http).

You'll use this to usually make a HTTP request to an API end point. The API end point returns a content that will will be used to instantiate your newly defined class, ready to be used in your view.