Bahan Sudut 7 - Pohon

Itu <mat-tree>, Angular Directive, digunakan untuk membuat pohon dengan gaya material untuk menampilkan data hierarki.

Dalam bab ini, kami akan menampilkan konfigurasi yang diperlukan untuk menggambar pohon menggunakan Material Angular.

Berikut adalah isi dari deskriptor modul yang dimodifikasi app.module.ts.

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

Berikut adalah konten dari file host HTML yang dimodifikasi app.component.html.

<mat-tree [dataSource] = "dataSource" [treeControl] = "treeControl">
   <mat-tree-node *matTreeNodeDef = "let node" matTreeNodeToggle matTreeNodePadding>
      <button mat-icon-button disabled></button>
      {{node.filename}} : {{node.type}}
   </mat-tree-node>
   <mat-tree-node *matTreeNodeDef = "let node;when: hasChild" matTreeNodePadding>
      <button mat-icon-button matTreeNodeToggle [attr.aria-label] = "'toggle ' + node.filename">
         <mat-icon class = "mat-icon-rtl-mirror">
            {{treeControl.isExpanded(node) ? 'expand_more' : 'chevron_right'}}
         </mat-icon>
      </button>
      {{node.filename}}
   </mat-tree-node>
</mat-tree>

Berikut adalah isi dari file ts yang dimodifikasi app.component.ts.

import {FlatTreeControl} from '@angular/cdk/tree';
import {Component, Injectable} from '@angular/core';
import {MatTreeFlatDataSource, MatTreeFlattener} from '@angular/material/tree';
import {BehaviorSubject, Observable, of as observableOf} from 'rxjs';
export class FileNode {
   children: FileNode[];
   filename: string;
   type: any;
}
export class FileFlatNode {
   constructor(
      public expandable: boolean, public filename: string, public level: number, public type: any) {}
}
const TREE_DATA = JSON.stringify({
   Documents: {
      angular: {
         src: {
            compiler: 'ts',
            core: 'ts'
         }
      },
      material2: {
         src: {
            button: 'ts',
            checkbox: 'ts',
            input: 'ts'
         }
      }
   }
});
@Injectable()
export class FileDatabase {
   dataChange = new BehaviorSubject<FileNode[]>([]);
   get data(): FileNode[] { return this.dataChange.value; }
   constructor() {
      this.initialize();
   }
   initialize() {
      const dataObject = JSON.parse(TREE_DATA);   
      const data = this.buildFileTree(dataObject, 0);
      this.dataChange.next(data);
   } 
   buildFileTree(obj: {[key: string]: any}, level: number): FileNode[] {
      return Object.keys(obj).reduce<FileNode[]>((accumulator, key) => {
         const value = obj[key];
         const node = new FileNode();
         node.filename = key;
         if (value != null) {
            if (typeof value === 'object') {
               node.children = this.buildFileTree(value, level + 1);
            } else {
               node.type = value;
            }
         }
         return accumulator.concat(node);
      }, []);
   }
}
@Component({
   selector: 'app-root',
   templateUrl: 'app.component.html',
   styleUrls: ['app.component.css'],
   providers: [FileDatabase]
})
export class AppComponent {
   treeControl: FlatTreeControl<FileFlatNode>;
   treeFlattener: MatTreeFlattener<FileNode, FileFlatNode>;
   dataSource: MatTreeFlatDataSource<FileNode, FileFlatNode>;
   constructor(database: FileDatabase) {
      this.treeFlattener = new MatTreeFlattener(this.transformer, this._getLevel,
      this._isExpandable, this._getChildren);
      this.treeControl = new FlatTreeControl<FileFlatNode>(this._getLevel, this._isExpandable);
      this.dataSource = new MatTreeFlatDataSource(this.treeControl, this.treeFlattener);
      database.dataChange.subscribe(data => this.dataSource.data = data);
   }
   transformer = (node: FileNode, level: number) => {
      return new FileFlatNode(!!node.children, node.filename, level, node.type);
   }
   private _getLevel = (node: FileFlatNode) => node.level;
   private _isExpandable = (node: FileFlatNode) => node.expandable;
   private _getChildren = (node: FileNode): Observable<FileNode[]> => observableOf(node.children);
   hasChild = (_: number, _nodeData: FileFlatNode) => _nodeData.expandable;
}

Hasil

Verifikasi hasilnya.

Detail

• Pertama, kita telah membuat pohon menggunakan mat-tree dan mat-tree-node.
• Kemudian, kita telah membuat sumber data dalam file ts dan mengikatnya dengan mat-tree.