这是一个材料数据表，它使用示例数据库来填充它。它还包括排序，分页和过滤。我已经设法使用具有排序和分页功能的Firestore数据（来自服务）填充表格。但是，我不能让过滤工作，我无法弄清楚为什么。我知道这是一个很长的镜头，但我希望有人可以告诉我如何实现Firestore数据库来代替下面的示例数据库。
example.ts：
import {Component, ElementRef, ViewChild} from '@angular/core';
import {DataSource} from '@angular/cdk/collections';
import {MatPaginator, MatSort} from '@angular/material';
import {SelectionModel} from '@angular/cdk/collections';
import {BehaviorSubject} from 'rxjs/BehaviorSubject';
import {Observable} from 'rxjs/Observable';
import 'rxjs/add/operator/startWith';
import 'rxjs/add/observable/merge';
import 'rxjs/add/observable/fromEvent';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/distinctUntilChanged';
import 'rxjs/add/operator/debounceTime';
/**
* @title Feature-rich data table
*/
@Component({
selector: 'table-overview-example',
styleUrls: ['table-overview-example.css'],
templateUrl: 'table-overview-example.html',
})
export class TableOverviewExample {
displayedColumns = ['select', 'userId', 'userName', 'progress', 'color'];
exampleDatabase = new ExampleDatabase();
selection = new SelectionModel<string>(true, []);
dataSource: ExampleDataSource | null;
@ViewChild(MatPaginator) paginator: MatPaginator;
@ViewChild(MatSort) sort: MatSort;
@ViewChild('filter') filter: ElementRef;
ngOnInit() {
this.dataSource = new ExampleDataSource(this.exampleDatabase, this.paginator, this.sort);
Observable.fromEvent(this.filter.nativeElement, 'keyup')
.debounceTime(150)
.distinctUntilChanged()
.subscribe(() => {
if (!this.dataSource) { return; }
this.dataSource.filter = this.filter.nativeElement.value;
});
}
isAllSelected(): boolean {
if (!this.dataSource) { return false; }
if (this.selection.isEmpty()) { return false; }
if (this.filter.nativeElement.value) {
return this.selection.selected.length == this.dataSource.renderedData.length;
} else {
return this.selection.selected.length == this.exampleDatabase.data.length;
}
}
masterToggle() {
if (!this.dataSource) { return; }
if (this.isAllSelected()) {
this.selection.clear();
} else if (this.filter.nativeElement.value) {
this.dataSource.renderedData.forEach(data => this.selection.select(data.id));
} else {
this.exampleDatabase.data.forEach(data => this.selection.select(data.id));
}
}
}
/** Constants used to fill up our data base. */
const COLORS = ['maroon', 'red', 'orange', 'yellow', 'olive', 'green', 'purple',
'fuchsia', 'lime', 'teal', 'aqua', 'blue', 'navy', 'black', 'gray'];
const NAMES = ['Maia', 'Asher', 'Olivia', 'Atticus', 'Amelia', 'Jack',
'Charlotte', 'Theodore', 'Isla', 'Oliver', 'Isabella', 'Jasper',
'Cora', 'Levi', 'Violet', 'Arthur', 'Mia', 'Thomas', 'Elizabeth'];
export interface UserData {
id: string;
name: string;
progress: string;
color: string;
}
/** An example database that the data source uses to retrieve data for the table. */
export class ExampleDatabase {
/** Stream that emits whenever the data has been modified. */
dataChange: BehaviorSubject<UserData[]> = new BehaviorSubject<UserData[]>([]);
get data(): UserData[] { return this.dataChange.value; }
constructor() {
// Fill up the database with 100 users.
for (let i = 0; i < 100; i++) { this.addUser(); }
}
/** Adds a new user to the database. */
addUser() {
const copiedData = this.data.slice();
copiedData.push(this.createNewUser());
this.dataChange.next(copiedData);
}
/** Builds and returns a new User. */
private createNewUser() {
const name =
NAMES[Math.round(Math.random() * (NAMES.length - 1))] + ' ' +
NAMES[Math.round(Math.random() * (NAMES.length - 1))].charAt(0) + '.';
return {
id: (this.data.length + 1).toString(),
name: name,
progress: Math.round(Math.random() * 100).toString(),
color: COLORS[Math.round(Math.random() * (COLORS.length - 1))]
};
}
}
/**
* Data source to provide what data should be rendered in the table. Note that the data source
* can retrieve its data in any way. In this case, the data source is provided a reference
* to a common data base, ExampleDatabase. It is not the data source's responsibility to manage
* the underlying data. Instead, it only needs to take the data and send the table exactly what
* should be rendered.
*/
export class ExampleDataSource extends DataSource<any> {
_filterChange = new BehaviorSubject('');
get filter(): string { return this._filterChange.value; }
set filter(filter: string) { this._filterChange.next(filter); }
filteredData: UserData[] = [];
renderedData: UserData[] = [];
constructor(private _exampleDatabase: ExampleDatabase,
private _paginator: MatPaginator,
private _sort: MatSort) {
super();
// Reset to the first page when the user changes the filter.
this._filterChange.subscribe(() => this._paginator.pageIndex = 0);
}
/** Connect function called by the table to retrieve one stream containing the data to render. */
connect(): Observable<UserData[]> {
// Listen for any changes in the base data, sorting, filtering, or pagination
const displayDataChanges = [
this._exampleDatabase.dataChange,
this._sort.sortChange,
this._filterChange,
this._paginator.page,
];
return Observable.merge(...displayDataChanges).map(() => {
// Filter data
this.filteredData = this._exampleDatabase.data.slice().filter((item: UserData) => {
let searchStr = (item.name + item.color).toLowerCase();
return searchStr.indexOf(this.filter.toLowerCase()) != -1;
});
// Sort filtered data
const sortedData = this.sortData(this.filteredData.slice());
// Grab the page's slice of the filtered sorted data.
const startIndex = this._paginator.pageIndex * this._paginator.pageSize;
this.renderedData = sortedData.splice(startIndex, this._paginator.pageSize);
return this.renderedData;
});
}
disconnect() {}
/** Returns a sorted copy of the database data. */
sortData(data: UserData[]): UserData[] {
if (!this._sort.active || this._sort.direction == '') { return data; }
return data.sort((a, b) => {
let propertyA: number|string = '';
let propertyB: number|string = '';
switch (this._sort.active) {
case 'userId': [propertyA, propertyB] = [a.id, b.id]; break;
case 'userName': [propertyA, propertyB] = [a.name, b.name]; break;
case 'progress': [propertyA, propertyB] = [a.progress, b.progress]; break;
case 'color': [propertyA, propertyB] = [a.color, b.color]; break;
}
let valueA = isNaN(+propertyA) ? propertyA : +propertyA;
let valueB = isNaN(+propertyB) ? propertyB : +propertyB;
return (valueA < valueB ? -1 : 1) * (this._sort.direction == 'asc' ? 1 : -1);
});
}
}
example.html的：
<div class="example-header" [style.display]="selection.isEmpty() ? '' : 'none'">
<mat-form-field floatPlaceholder="never">
<input matInput #filter placeholder="Filter users">
</mat-form-field>
</div>
<div class="example-header example-selection-header"
*ngIf="!selection.isEmpty()">
{{selection.selected.length}}
{{selection.selected.length == 1 ? 'user' : 'users'}}
selected
</div>
<div class="example-container mat-elevation-z8">
<mat-table #table [dataSource]="dataSource" matSort>
<!--- Note that these columns can be defined in any order.
The actual rendered columns are set as a property on the row definition" -->
<!-- Checkbox Column -->
<ng-container matColumnDef="select">
<mat-header-cell *matHeaderCellDef>
<mat-checkbox (change)="$event ? masterToggle() : null"
[checked]="isAllSelected()"
[indeterminate]="selection.hasValue() && !isAllSelected()">
</mat-checkbox>
</mat-header-cell>
<mat-cell *matCellDef="let row">
<mat-checkbox (click)="$event.stopPropagation()"
(change)="$event ? selection.toggle(row.id) : null"
[checked]="selection.isSelected(row.id)">
</mat-checkbox>
</mat-cell>
</ng-container>
<!-- ID Column -->
<ng-container matColumnDef="userId">
<mat-header-cell *matHeaderCellDef mat-sort-header> ID </mat-header-cell>
<mat-cell *matCellDef="let row"> {{row.id}} </mat-cell>
</ng-container>
<!-- Progress Column -->
<ng-container matColumnDef="progress">
<mat-header-cell *matHeaderCellDef mat-sort-header> Progress </mat-header-cell>
<mat-cell *matCellDef="let row"> {{row.progress}}% </mat-cell>
</ng-container>
<!-- Name Column -->
<ng-container matColumnDef="userName">
<mat-header-cell *matHeaderCellDef mat-sort-header> Name </mat-header-cell>
<mat-cell *matCellDef="let row"> {{row.name}} </mat-cell>
</ng-container>
<!-- Color Column -->
<ng-container matColumnDef="color">
<mat-header-cell *matHeaderCellDef mat-sort-header> Color </mat-header-cell>
<mat-cell *matCellDef="let row" [style.color]="row.color"> {{row.color}} </mat-cell>
</ng-container>
<mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
<mat-row *matRowDef="let row; columns: displayedColumns;"
[class.example-selected-row]="selection.isSelected(row.id)"
(click)="selection.toggle(row.id)">
</mat-row>
</mat-table>
<div class="example-no-results"
[style.display]="dataSource.renderedData.length == 0 ? '' : 'none'">
No users found matching filter.
</div>
<mat-paginator #paginator
[length]="dataSource.filteredData.length"
[pageIndex]="0"
[pageSize]="25"
[pageSizeOptions]="[5, 10, 25, 100]">
</mat-paginator>
</div>
答案 0 :(得分：2)
在对数据进行排序时尝试重构和放置过滤器，这就是我进行过滤，分页和排序的方法。在重构其余代码以使用重构数据源类之前，您将收到错误：
export class ExampleDataSource extends DataSource<any> {
_filterChange = new BehaviorSubject('');
get filter(): string { return this._filterChange.value; }
set filter(filter: string) { this._filterChange.next(filter); }
renderedData: UserData[] = [];
constructor(private _exampleDatabase: ExampleDatabase,
private _paginator: MatPaginator,
private _sort: MatSort) {
super();
}
connect(): Observable<Data[]> {
const displayDataChanges = [
this._exampleDatabase.dataChange,
this._paginator.page,
this._sort.sortChange,
this._filterChange
];
return Observable.merge(...displayDataChanges).map(() => {
const startIndex = this._paginator.pageIndex * this._paginator.pageSize;
this.renderedData= this.sortData();
return this.renderedData.splice(startIndex, this._paginator.pageSize);
});
}
disconnect() {}
sortData(): Data[] {
const data = this._exampleDatabase.data.slice().filter((item: Data) => {
let searchStr = (item.name + item.color).toLowerCase();
return searchStr.indexOf(this.filter.toLowerCase()) != -1;
});
if (!this._sort.active || this._sort.direction == '') { return data; }
return data.sort((a, b) => {
let propertyA: number|string = '';
let propertyB: number|string = '';
switch (this._sort.active) {
case 'userId': [propertyA, propertyB] = [a.id, b.id]; break;
case 'userName': [propertyA, propertyB] = [a.name, b.name]; break;
case 'progress': [propertyA, propertyB] = [a.progress, b.progress]; break;
case 'color': [propertyA, propertyB] = [a.color, b.color]; break;
}
let valueA = isNaN(+propertyA) ? propertyA : +propertyA;
let valueB = isNaN(+propertyB) ? propertyB : +propertyB;
return (valueA < valueB ? -1 : 1) * (this._sort.direction == 'asc' ? 1 : -1);
});
}
}