Я пытаюсь реализовать таблицу данных Material2. Но я не могу понять, как правильно использовать его.
import {Component, ElementRef, ViewChild} from '@angular/core';
import {DataSource} from '@angular/cdk';
import {BehaviorSubject} from 'rxjs/BehaviorSubject';
import {Observable} from 'rxjs/Observable';
import 'rxjs/add/operator/startWith';
import 'rxjs/add/observable/merge';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/debounceTime';
import 'rxjs/add/operator/distinctUntilChanged';
import 'rxjs/add/observable/fromEvent';
@Component({
selector: 'table-filtering-example',
styleUrls: ['table-filtering-example.css'],
templateUrl: 'table-filtering-example.html',
})
export class TableFilteringExample {
displayedColumns = ['userId', 'userName', 'progress', 'color'];
exampleDatabase = new ExampleDatabase();
dataSource: ExampleDataSource | null;
@ViewChild('filter') filter: ElementRef;
ngOnInit() {
this.dataSource = new ExampleDataSource(this.exampleDatabase);
Observable.fromEvent(this.filter.nativeElement, 'keyup')
.debounceTime(150)
.distinctUntilChanged()
.subscribe(() => {
if (!this.dataSource) { return; }
this.dataSource.filter = this.filter.nativeElement.value;
});
}
}
/** 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 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); }
constructor(private _exampleDatabase: ExampleDatabase) {
super();
}
/** Connect function called by the table to retrieve one stream containing the data to render. */
connect(): Observable<UserData[]> {
const displayDataChanges = [
this._exampleDatabase.dataChange,
this._filterChange,
];
return Observable.merge(...displayDataChanges).map(() => {
return this._exampleDatabase.data.slice().filter((item: UserData) => {
let searchStr = (item.name + item.color).toLowerCase();
return searchStr.indexOf(this.filter.toLowerCase()) != -1;
});
});
}
disconnect() {}
}
Выше код кода, который очень запутан для меня. Даже их документация очень бедна. Может кто-нибудь объяснить, что такое поток выше кода?
Пожалуйста, проигнорируйте, если вы считаете, что вопрос слишком простой, чтобы спросить?
