docs(tree): add more tree demos

src/demo-app/demo-app/demo-module.ts

@@ -57,12 +57,12 @@ import {
 } from '../tabs/tabs-demo';
 import {ToolbarDemo} from '../toolbar/toolbar-demo';
 import {TooltipDemo} from '../tooltip/tooltip-demo';
-import {TreeDemo} from '../tree/tree-demo';
 import {TypographyDemo} from '../typography/typography-demo';
 import {DemoApp, Home} from './demo-app';
 import {DEMO_APP_ROUTES} from './routes';
 import {TableDemoModule} from '../table/table-demo-module';
 import {BadgeDemo} from '../badge/badge-demo';
+import {TreeDemoModule} from '../tree/tree-demo-module';
 
 @NgModule({
   imports: [
@@ -73,6 +73,7 @@ import {BadgeDemo} from '../badge/badge-demo';
     DemoMaterialModule,
     LayoutModule,
     TableDemoModule,
+    TreeDemoModule,
   ],
   declarations: [
     AutocompleteDemo,
@@ -127,7 +128,6 @@ import {BadgeDemo} from '../badge/badge-demo';
     TabsDemo,
     ToolbarDemo,
     TooltipDemo,
-    TreeDemo,
     TypographyDemo,
     ExampleBottomSheet,
   ],

src/demo-app/tree/checklist-tree-demo/checklist-database.ts

@@ -0,0 +1,101 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import {Injectable} from '@angular/core';
+import {BehaviorSubject} from 'rxjs/BehaviorSubject';
+
+/**
+ * Node for to-do item
+ */
+export class TodoItemNode {
+  children: TodoItemNode[];
+  item: string;
+}
+
+/** Flat to-do item node with expandable and level information */
+export class TodoItemFlatNode {
+  item: string;
+  level: number;
+  expandable: boolean;
+}
+
+/**
+ * The Json object for to-do list data.
+ */
+const TREE_DATA = {
+  'Reminders': [
+    'Cook dinner',
+    'Read the Material Design spec',
+    'Upgrade Application to Angular'
+  ],
+  'Groceries': {
+    'Organic eggs': null,
+    'Protein Powder': null,
+    'Almond Meal flour': null,
+    'Fruits': {
+      'Apple': null,
+      'Orange': null,
+      'Berries': ['Blueberry', 'Raspberry']
+    }
+  }
+};
+
+/**
+ * Checklist database, it can build a tree structured Json object.
+ * Each node in Json object represents a to-do item or a category.
+ * If a node is a category, it has children items and new items can be added under the category.
+ */
+@Injectable()
+export class ChecklistDatabase {
+  dataChange: BehaviorSubject<TodoItemNode[]> = new BehaviorSubject<TodoItemNode[]>([]);
+
+  get data(): TodoItemNode[] { return this.dataChange.value; }
+
+  constructor() {
+    this.initialize();
+  }
+
+  initialize() {
+    // Build the tree nodes from Json object. The result is a list of `TodoItemNode` with nested
+    //     file node as children.
+    const data = this.buildFileTree(TREE_DATA, 0);
+
+    // Notify the change.
+    this.dataChange.next(data);
+  }
+
+  /**
+   * Build the file structure tree. The `value` is the Json object, or a sub-tree of a Json object.
+   * The return value is the list of `TodoItemNode`.
+   */
+  buildFileTree(value: any, level: number) {
+    let data: any[] = [];
+    for (let k in value) {
+      let v = value[k];
+      let node = new TodoItemNode();
+      node.item = `${k}`;
+      if (v === null || v === undefined) {
+        // no action
+      } else if (typeof v === 'object') {
+        node.children = this.buildFileTree(v, level + 1);
+      } else {
+        node.item = v;
+      }
+      data.push(node);
+    }
+    return data;
+  }
+
+  /** Add an item to to-do list */
+  insertItem(parent: TodoItemNode, name: string) {
+    const child = <TodoItemNode>{item: name};
+    if (parent.children) {
+      parent.children.push(child);
+      this.dataChange.next(this.data);
+    }
+  }
+}

src/demo-app/tree/checklist-tree-demo/checklist-tree-demo.html

@@ -0,0 +1,28 @@
+<mat-tree [dataSource]="dataSource" [treeControl]="treeControl">
+  <mat-tree-node *matTreeNodeDef="let node" matTreeNodeToggle matTreeNodePadding>
+    <button mat-icon-button disabled></button>
+    <mat-checkbox class="checklist-leaf-node"
+                  [checked]="checklistSelection.isSelected(node)"
+                  (change)="checklistSelection.toggle(node);">{{node.item}}</mat-checkbox>
+  </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>
+        {{treeControl.isExpanded(node) ? 'expand_more' : 'chevron_right'}}
+      </mat-icon>
+    </button>
+    <mat-checkbox [checked]="descendantsAllSelected(node)"
+                  [indeterminate]="descendantsPartiallySelected(node)"
+                  (change)="todoItemSelectionToggle(node)">{{node.item}}</mat-checkbox>
+    <button mat-icon-button (click)="setParent(node)"><mat-icon>add</mat-icon></button>
+  </mat-tree-node>
+</mat-tree>
+
+
+Selected parent: {{selectedParent ? selectedParent.item : 'No selected'}}
+<br>
+<mat-form-field>
+  <input matInput [(ngModel)]="newItemName" placeholder="Add an item"/>
+</mat-form-field>
+<button mat-button (click)="addNode()">Add node</button>

src/demo-app/tree/checklist-tree-demo/checklist-tree-demo.ts

@@ -0,0 +1,117 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {Component} from '@angular/core';
+import {SelectionModel} from '@angular/cdk/collections';
+import {FlatTreeControl} from '@angular/cdk/tree';
+import {MatTreeFlattener, MatTreeFlatDataSource} from '@angular/material/tree';
+import {of as ofObservable} from 'rxjs/observable/of';
+import {TodoItemNode, TodoItemFlatNode, ChecklistDatabase} from './checklist-database';
+
+/**
+ * A nested checklist example using tree component.
+ * Each item/category has a checkbox, and user can check/uncheck a to-do item.
+ */
+@Component({
+  moduleId: module.id,
+  selector: 'checklist-tree-demo',
+  templateUrl: 'checklist-tree-demo.html',
+  styleUrls: ['checklist-tree-demo.css'],
+  providers: [ChecklistDatabase]
+})
+export class ChecklistTreeDemo {
+  /** Map from flat node to nested node. This helps us finding the nested node to be modified */
+  flatNodeMap: Map<TodoItemFlatNode, TodoItemNode> = new Map<TodoItemFlatNode, TodoItemNode>();
+
+  /** Map from nested node to flattened node. This helps us to keep the same object for selection */
+  nestedNodeMap: Map<TodoItemNode, TodoItemFlatNode> = new Map<TodoItemNode, TodoItemFlatNode>();
+
+  /** A selected parent node to be inserted */
+  selectedParent: TodoItemFlatNode | null = null;
+
+  /** The new item's name */
+  newItemName: string = '';
+
+  treeControl: FlatTreeControl<TodoItemFlatNode>;
+
+  treeFlattener: MatTreeFlattener<TodoItemNode, TodoItemFlatNode>;
+
+  dataSource: MatTreeFlatDataSource<TodoItemNode, TodoItemFlatNode>;
+
+  /** The selection for checklist */
+  checklistSelection = new SelectionModel<TodoItemFlatNode>(true /* multiple */);
+
+  constructor(private database: ChecklistDatabase) {
+    this.treeFlattener = new MatTreeFlattener(this.transformer, this.getLevel,
+      this.isExpandable, this.getChildren);
+    this.treeControl = new FlatTreeControl<TodoItemFlatNode>(this.getLevel, this.isExpandable);
+    this.dataSource = new MatTreeFlatDataSource(this.treeControl, this.treeFlattener);
+
+    database.dataChange.subscribe(data => {
+      this.dataSource.data = data;
+    });
+  }
+
+  getLevel = (node: TodoItemFlatNode) => { return node.level; };
+
+  isExpandable = (node: TodoItemFlatNode) => { return node.expandable; };
+
+  getChildren = (node: TodoItemNode) => { return ofObservable(node.children); };
+
+  hasChild = (_: number, _nodeData: TodoItemFlatNode) => { return _nodeData.expandable; };
+
+  /**
+   * Transformer to convert nested node to flat node. Record the nodes in maps for later use.
+   */
+  transformer = (node: TodoItemNode, level: number) => {
+    let flatNode = this.nestedNodeMap.has(node)
+      ? this.nestedNodeMap.get(node)!
+      : new TodoItemFlatNode();
+    flatNode.item = node.item;
+    flatNode.level = level;
+    flatNode.expandable = !!node.children;
+    this.flatNodeMap.set(flatNode, node);
+    this.nestedNodeMap.set(node, flatNode);
+    return flatNode;
+  }
+
+  /** Whether all the descendants of the node are selected */
+  descendantsAllSelected(node: TodoItemFlatNode): boolean {
+    const descendants = this.treeControl.getDescendants(node);
+    return descendants.every(child => this.checklistSelection.isSelected(child));
+  }
+
+  /** Whether part of the descendants are selected */
+  descendantsPartiallySelected(node: TodoItemFlatNode): boolean {
+    const descendants = this.treeControl.getDescendants(node);
+    const result = descendants.some(child => this.checklistSelection.isSelected(child));
+    return result && !this.descendantsAllSelected(node);
+  }
+
+  /** Toggle the to-do item selection. Select/deselect all the descendants node */
+  todoItemSelectionToggle(node: TodoItemFlatNode): void {
+    this.checklistSelection.toggle(node);
+    const descendants = this.treeControl.getDescendants(node);
+    this.checklistSelection.isSelected(node)
+        ? this.checklistSelection.select(...descendants)
+        : this.checklistSelection.deselect(...descendants);
+  }
+
+  /** Insert a new item with name `newItemName` to be under category `selectedParent`. */
+  addNode() {
+    if (this.selectedParent) {
+      const parentNode = this.flatNodeMap.get(this.selectedParent);
+      this.database.insertItem(parentNode!, this.newItemName);
+    }
+  }
+
+  /** Select the category so we can insert the new item. */
+  setParent(node: TodoItemFlatNode) {
+    this.selectedParent = node;
+  }
+}

src/demo-app/tree/dynamic-tree-demo/dynamic-database.ts

@@ -0,0 +1,115 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import {Injectable} from '@angular/core';
+import {FlatTreeControl} from '@angular/cdk/tree';
+import {CollectionViewer, SelectionChange} from '@angular/cdk/collections';
+import {BehaviorSubject} from 'rxjs/BehaviorSubject';
+import {merge} from 'rxjs/observable/merge';
+import {map} from 'rxjs/operators/map';
+
+/** Flat node with expandable and level information */
+export class DynamicFlatNode {
+  constructor(public item: string, public level: number = 1, public expandable: boolean = false) {}
+}
+
+
+/**
+ * Database for dynamic data. When expanding a node in the tree, the data source will need to fetch
+ * the descendants data from the database.
+ */
+export class DynamicDatabase {
+  dataMap = new Map([
+    ['Fruits', ['Apple', 'Orange', 'Banana']],
+    ['Vegetables', ['Tomato', 'Potato', 'Onion']],
+    ['Apple', ['Fuji', 'Macintosh']],
+    ['Onion', ['Yellow', 'White', 'Purple']]
+  ]);
+
+  rootLevelNodes = ['Fruits', 'Vegetables'];
+
+  /** Initial data from database */
+  initialData(): DynamicFlatNode[] {
+    return this.rootLevelNodes.map(name => new DynamicFlatNode(name, 1, true));
+  }
+
+
+  getChildren(node: string): string[] | undefined {
+    return this.dataMap.get(node);
+  }
+
+  isExpandable(node: string): boolean {
+    return this.dataMap.has(node);
+  }
+}
+/**
+ * File database, it can build a tree structured Json object from string.
+ * Each node in Json object represents a file or a directory. For a file, it has filename and type.
+ * For a directory, it has filename and children (a list of files or directories).
+ * The input will be a json object string, and the output is a list of `FileNode` with nested
+ * structure.
+ */
+@Injectable()
+export class DynamicDataSource {
+
+  dataChange: BehaviorSubject<DynamicFlatNode[]> = new BehaviorSubject<DynamicFlatNode[]>([]);
+
+  get data(): DynamicFlatNode[] { return this.dataChange.value; }
+  set data(value: DynamicFlatNode[]) {
+    this.treeControl.dataNodes = value;
+    this.dataChange.next(value);
+  }
+
+  constructor(private treeControl: FlatTreeControl<DynamicFlatNode>,
+              private database: DynamicDatabase) {}
+
+  connect(collectionViewer: CollectionViewer) {
+    const changes = [
+      collectionViewer.viewChange,
+      this.treeControl.expansionModel.onChange!,
+    ];
+    return merge(...changes).pipe(map((change) => {
+      if ((change as SelectionChange<DynamicFlatNode>).added ||
+          (change as SelectionChange<DynamicFlatNode>).removed) {
+        this.handleTreeControl(change as SelectionChange<DynamicFlatNode>);
+      }
+      return this.data;
+    }));
+  }
+
+  /** Handle expand/collapse behaviors */
+  handleTreeControl(change: SelectionChange<DynamicFlatNode>) {
+    if (change.added) {
+      change.added.forEach((node) => this.toggleNode(node, true));
+    }
+    if (change.removed) {
+      change.removed.forEach((node) => this.toggleNode(node, false));
+    }
+  }
+
+  /**
+   * Toggle the node, remove from display list
+   */
+  toggleNode(node: DynamicFlatNode, expand: boolean) {
+    const children = this.database.getChildren(node.item);
+    const index = this.data.indexOf(node);
+    if (!children || index < 0) { // If no children, or cannot find the node, no op
+      return;
+    }
+
+    if (expand) {
+      const nodes = children.map(name =>
+          new DynamicFlatNode(name, node.level + 1, this.database.isExpandable(name)));
+      this.data.splice(index + 1, 0, ...nodes);
+    } else {
+      this.data.splice(index + 1, children.length);
+    }
+
+    // notify the change
+    this.dataChange.next(this.data);
+  }
+}