Angular Material 7 - 排序标题

<mat-sort-header> 和 matSort（一种 Angular 指令）用于向表头添加排序功能。

在本章中，我们将展示使用 Angular Material 显示排序标题所需的配置。

以下是修改后的模块描述符app.module.ts的内容。

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppComponent } from './app.component';
import {BrowserAnimationsModule} from '@angular/platform-browser/animations';
import {MatSortModule} from '@angular/material'
import {FormsModule, ReactiveFormsModule} from '@angular/forms';
@NgModule({
   declarations: [
      AppComponent
   ],
   imports: [
      BrowserModule,
      BrowserAnimationsModule,
      MatSortModule,
      FormsModule,
      ReactiveFormsModule
   ],
   providers: [],
   bootstrap: [AppComponent]
})
export class AppModule { }

以下是修改后的HTML主机文件app.component.html的内容。

<table matSort (matSortChange) = "sortFood($event)">
   <tr>
      <th mat-sort-header = "name">Dessert (100g)</th>
      <th mat-sort-header = "calories">Calories</th>
      <th mat-sort-header = "fat">Fat (g)</th>
      <th mat-sort-header = "carbs">Carbs (g)</th>
      <th mat-sort-header = "protein">Protein (g)</th>
   </tr>
   <tr *ngFor = "let food of sortedFood">
      <td>{{food.name}}</td>
      <td>{{food.calories}}</td>
      <td>{{food.fat}}</td>
      <td>{{food.carbs}}</td>
      <td>{{food.protein}}</td>
   </tr>
</table>

以下是修改后的ts文件app.component.ts的内容。

import {Component, Injectable} from '@angular/core';
import {Sort} from '@angular/material';
export interface Food {
   calories: number;
   carbs: number;
   fat: number;
   name: string;
   protein: number;
}
@Component({
   selector: 'app-root',
   templateUrl: 'app.component.html',
   styleUrls: ['app.component.css']
})
export class AppComponent { 
   foods: Food[] = [
      {name: 'Yogurt', calories: 159, fat: 6, carbs: 24, protein: 4},
      {name: 'Sandwich', calories: 237, fat: 9, carbs: 37, protein: 4},
      {name: 'Eclairs', calories: 262, fat: 16, carbs: 24, protein: 6},
      {name: 'Cupcakes', calories: 305, fat: 4, carbs: 67, protein: 4},
      {name: 'Gingerbreads', calories: 356, fat: 16, carbs: 49, protein: 4},
   ];
   sortedFood: Food[];
   constructor() {
      this.sortedFood = this.foods.slice();
   }
   sortFood(sort: Sort) {
      const data = this.foods.slice();
      if (!sort.active || sort.direction === '') {
         this.sortedFood = data;
         return;
      }
      this.sortedFood = data.sort((a, b) => {
         const isAsc = sort.direction === 'asc';
         switch (sort.active) {
            case 'name': return compare(a.name, b.name, isAsc);
            case 'calories': return compare(a.calories, b.calories, isAsc);
            case 'fat': return compare(a.fat, b.fat, isAsc);
            case 'carbs': return compare(a.carbs, b.carbs, isAsc);
            case 'protein': return compare(a.protein, b.protein, isAsc);
            default: return 0;
         } 
      });
   }
}
function compare(a: number | string, b: number | string, isAsc: boolean) {
   return (a < b ? -1 : 1) * (isAsc ? 1 : -1);
}