Mat-tab材质angular6 selectedIndex不适用于* ngFor

问题描述

我显示了几个带有循环的选项卡ngFor使用Angular Material选项卡.这可以正常工作，但是现在我想在初始化时打开第二个选项卡，而不是第一个选项卡.因此，我在mat-tab-group组中添加了selectedIndex属性，但是它不起作用，并且仍然在第一个选项卡上继续打开.

I display several tabs with a loop ngFor using Angular Material tabs.This works properly however now I would like to open the second tab when initialised and not the first tab.Therefore, I add the property selectedIndex in the mat-tab-group but it doesn't work and still continues to open on the first tab.

HTML

<mat-tab-group class="col-10 offset-1" (selectedTabChange)="onTabChanged($event)" [selectedIndex]="1">
  <mat-tab label={{tab.name}} *ngFor="let tab of tabs; let index = index">
    <div>
      Values: {{tab.values}}
    </div>
  </mat-tab>
</mat-tab-group>

使用服务从ngOnInit的服务器中获取变量"tabs" ，如下所示:

The variable "tabs" is fetched with a service from the server in ngOnInit like this:

组件

this.api.getDataset(this.route.snapshot.params["experimentid"]).subscribe(
  res => {
    this.tabs = res;
  },
  err => {
    console.log(err);
  }
);

我认为它来自这里，因为如果我手动设置选项卡而不请求服务器，它将起作用.像这样:

I think it comes from here because if I set the tabs manually without requesting to the server it works. Like this:

this.tabs = [{name: "X2", values: "52"}, {name: "Z2", values: "52"}, {name: "R2", values: "52"}]

推荐答案

您可以在服务数据可用后设置selectedIndex.您需要进行以下更改:

You can set the selectedIndex after your service data is available. You need to do below changes:

1. 通过声明以下属性来获取对组件(其模板包含mat-tab-group的组件)中的MatTabGroup实例的引用:

1. Get hold of a reference to MatTabGroup instance in your component (the component whose template contains mat-tab-group) by declaring below attribute:

@ViewChild(MatTabGroup) tabGroup: MatTabGroup;

然后在更新tabs

.subscribe(
  res => {
    this.tabs = res;
    this.tabGroup.selectedIndex = 1;
  },

总体而言，您的组件可能看起来如下所示:

Overall, you component may look somewhat like below:

import {Component, OnInit, ViewChild } from '@angular/core';
import { MatTabGroup } from '@angular/material';

@Component({
  selector: 'tab-group-basic-example',
  templateUrl: 'tab-group-basic-example.html',
  styleUrls: ['tab-group-basic-example.css'],
})
export class TabGroupBasicExample implements OnInit {

  @ViewChild(MatTabGroup) tabGroup: MatTabGroup;

  tabs = [];

  ngOnInit() {
    this.api.getDataset(experimentId).subscribe(
      res => {
          this.tabs = res;
          this.tabGroup.selectedIndex = 1;
      },
      err => {
          console.log(err);
      }
    );
  }
}

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