Adding expansion panel to the row inside angular material table

Question

I am trying to add an expansion panel(may be a new component) something similar to the mat-accordion to show the detailed view inside a mat-table row on click. I have attached a plunker to demonstrate the requirement. http://plnkr.co/edit/mBGT3D1JV5rXXRiEwCAc?p=info

This is the demo angular material table that I am trying to add the expanded column to and I have added plunker on the html data table

<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>

Answer 1

In the angular2 material docs, there is now an example for a table with expandable rows: https://material.angular.io/components/table/examples

Here's a Stackblitz example but I've also included the snippets from the Angular Material docs below

import {Component} from '@angular/core';
import {animate, state, style, transition, trigger} from '@angular/animations';

/**
 * @title Table with expandable rows
 */
@Component({
  selector: 'table-expandable-rows-example',
  styleUrls: ['table-expandable-rows-example.css'],
  templateUrl: 'table-expandable-rows-example.html',
  animations: [
    trigger('detailExpand', [
      state('collapsed', style({height: '0px', minHeight: '0'})),
      state('expanded', style({height: '*'})),
      transition('expanded <=> collapsed', animate('225ms cubic-bezier(0.4, 0.0, 0.2, 1)')),
    ]),
  ],
})
export class TableExpandableRowsExample {
  dataSource = ELEMENT_DATA;
  columnsToDisplay = ['name', 'weight', 'symbol', 'position'];
  expandedElement: PeriodicElement | null;
}

export interface PeriodicElement {
  name: string;
  position: number;
  weight: number;
  symbol: string;
  description: string;
}

const ELEMENT_DATA: PeriodicElement[] = [
  {
    position: 1,
    name: 'Hydrogen',
    weight: 1.0079,
    symbol: 'H',
    description: `Hydrogen is a chemical element with symbol H and atomic number 1. With a standard
        atomic weight of 1.008, hydrogen is the lightest element on the periodic table.`
  }, {
    position: 2,
    name: 'Helium',
    weight: 4.0026,
    symbol: 'He',
    description: `Helium is a chemical element with symbol He and atomic number 2. It is a
        colorless, odorless, tasteless, non-toxic, inert, monatomic gas, the first in the noble gas
        group in the periodic table. Its boiling point is the lowest among all the elements.`
  }, {
    position: 3,
    name: 'Lithium',
    weight: 6.941,
    symbol: 'Li',
    description: `Lithium is a chemical element with symbol Li and atomic number 3. It is a soft,
        silvery-white alkali metal. Under standard conditions, it is the lightest metal and the
        lightest solid element.`
  }, {
    position: 4,
    name: 'Beryllium',
    weight: 9.0122,
    symbol: 'Be',
    description: `Beryllium is a chemical element with symbol Be and atomic number 4. It is a
        relatively rare element in the universe, usually occurring as a product of the spallation of
        larger atomic nuclei that have collided with cosmic rays.`
  }, {
    position: 5,
    name: 'Boron',
    weight: 10.811,
    symbol: 'B',
    description: `Boron is a chemical element with symbol B and atomic number 5. Produced entirely
        by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a
        low-abundance element in the Solar system and in the Earth's crust.`
  }, {
    position: 6,
    name: 'Carbon',
    weight: 12.0107,
    symbol: 'C',
    description: `Carbon is a chemical element with symbol C and atomic number 6. It is nonmetallic
        and tetravalent—making four electrons available to form covalent chemical bonds. It belongs
        to group 14 of the periodic table.`
  }, {
    position: 7,
    name: 'Nitrogen',
    weight: 14.0067,
    symbol: 'N',
    description: `Nitrogen is a chemical element with symbol N and atomic number 7. It was first
        discovered and isolated by Scottish physician Daniel Rutherford in 1772.`
  }, {
    position: 8,
    name: 'Oxygen',
    weight: 15.9994,
    symbol: 'O',
    description: `Oxygen is a chemical element with symbol O and atomic number 8. It is a member of
         the chalcogen group on the periodic table, a highly reactive nonmetal, and an oxidizing
         agent that readily forms oxides with most elements as well as with other compounds.`
  }, {
    position: 9,
    name: 'Fluorine',
    weight: 18.9984,
    symbol: 'F',
    description: `Fluorine is a chemical element with symbol F and atomic number 9. It is the
        lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard
        conditions.`
  }, {
    position: 10,
    name: 'Neon',
    weight: 20.1797,
    symbol: 'Ne',
    description: `Neon is a chemical element with symbol Ne and atomic number 10. It is a noble gas.
        Neon is a colorless, odorless, inert monatomic gas under standard conditions, with about
        two-thirds the density of air.`
  },
];

table {
  width: 100%;
}

tr.example-detail-row {
  height: 0;
}

tr.example-element-row:not(.example-expanded-row):hover {
  background: whitesmoke;
}

tr.example-element-row:not(.example-expanded-row):active {
  background: #efefef;
}

.example-element-row td {
  border-bottom-width: 0;
}

.example-element-detail {
  overflow: hidden;
  display: flex;
}

.example-element-diagram {
  min-width: 80px;
  border: 2px solid black;
  padding: 8px;
  font-weight: lighter;
  margin: 8px 0;
  height: 104px;
}

.example-element-symbol {
  font-weight: bold;
  font-size: 40px;
  line-height: normal;
}

.example-element-description {
  padding: 16px;
}

.example-element-description-attribution {
  opacity: 0.5;
}

<table mat-table
       [dataSource]="dataSource" multiTemplateDataRows
       class="mat-elevation-z8">
  <ng-container matColumnDef="{{column}}" *ngFor="let column of columnsToDisplay">
    <th mat-header-cell *matHeaderCellDef> {{column}} </th>
    <td mat-cell *matCellDef="let element"> {{element[column]}} </td>
  </ng-container>

  <!-- Expanded Content Column - The detail row is made up of this one column that spans across all columns -->
  <ng-container matColumnDef="expandedDetail">
    <td mat-cell *matCellDef="let element" [attr.colspan]="columnsToDisplay.length">
      <div class="example-element-detail"
           [@detailExpand]="element == expandedElement ? 'expanded' : 'collapsed'">
        <div class="example-element-diagram">
          <div class="example-element-position"> {{element.position}} </div>
          <div class="example-element-symbol"> {{element.symbol}} </div>
          <div class="example-element-name"> {{element.name}} </div>
          <div class="example-element-weight"> {{element.weight}} </div>
        </div>
        <div class="example-element-description">
          {{element.description}}
          <span class="example-element-description-attribution"> -- Wikipedia </span>
        </div>
      </div>
    </td>
  </ng-container>

  <tr mat-header-row *matHeaderRowDef="columnsToDisplay"></tr>
  <tr mat-row *matRowDef="let element; columns: columnsToDisplay;"
      class="example-element-row"
      [class.example-expanded-row]="expandedElement === element"
      (click)="expandedElement = expandedElement === element ? null : element">
  </tr>
  <tr mat-row *matRowDef="let row; columns: ['expandedDetail']" class="example-detail-row"></tr>
</table>

The key bits you need are:

• component.html / markup
  • multiTemplateDataRows directive on mat-table
  • a dedicated column for the expanded row (matColumnDef="expandedDetail" in the provided example). Note the colspan attribute that makes this span the whole table.
  • a dedicated row for the expanded row. this will contain the expanded column ^
  • detailExpand directive on the div that contains the details within expanded row [@detailExpand]="element == expandedElement ? 'expanded' : 'collapsed'"
• component.ts
  • animations in the @Component decorator. these toggle the expanded/collapse state in the UI
  • a property (expandedElement in this case) to keep track of which row is expanded
• component.scss

  • styling to hide the overflow of the expanded row

    .example-element-detail { overflow: hidden; }