在Angular 2中有没有聪明的方法返回到最后一页?
类似的
this._router.navigate(LASTPAGE);
例如,C页有一个“返回”按钮,
A页-> C页,点击返回A页。 B页-> C页,点击它,回到B页。
路由器有这个历史信息吗?
在Angular 2中有没有聪明的方法返回到最后一页?
类似的
this._router.navigate(LASTPAGE);
例如,C页有一个“返回”按钮,
A页-> C页,点击返回A页。 B页-> C页,点击它,回到B页。
路由器有这个历史信息吗?
当前回答
在这些精彩的答案之后,我希望我的答案能找到一些人,并帮助他们。我编写了一个小服务来跟踪路线历史。开始了。
import { Injectable } from '@angular/core';
import { NavigationEnd, Router } from '@angular/router';
import { filter } from 'rxjs/operators';
@Injectable()
export class RouteInterceptorService {
private _previousUrl: string;
private _currentUrl: string;
private _routeHistory: string[];
constructor(router: Router) {
this._routeHistory = [];
router.events
.pipe(filter(event => event instanceof NavigationEnd))
.subscribe((event: NavigationEnd) => {
this._setURLs(event);
});
}
private _setURLs(event: NavigationEnd): void {
const tempUrl = this._currentUrl;
this._previousUrl = tempUrl;
this._currentUrl = event.urlAfterRedirects;
this._routeHistory.push(event.urlAfterRedirects);
}
get previousUrl(): string {
return this._previousUrl;
}
get currentUrl(): string {
return this._currentUrl;
}
get routeHistory(): string[] {
return this._routeHistory;
}
}
其他回答
如果你使用的是最新的Angular/TypeScript,请确保你显式导入
import { Location } from '@angular/common';
and
onCancel() {
this.location.back();
}
要返回而不刷新页面,我们可以像下面这样在html中做 javascript: history.back ()
<a class="btn btn-danger" href="javascript:history.back()">Go Back</a>
实际上,你可以利用内置的位置服务,它拥有一个“返回”API。
这里(TypeScript中):
import {Component} from '@angular/core';
import {Location} from '@angular/common';
@Component({
// component's declarations here
})
class SomeComponent {
constructor(private _location: Location)
{}
backClicked() {
this._location.back();
}
}
编辑:正如@charith所提到的。Location应该从@angular/common中导入,所以从@angular/common中导入{Location};线条很重要。
在这些精彩的答案之后,我希望我的答案能找到一些人,并帮助他们。我编写了一个小服务来跟踪路线历史。开始了。
import { Injectable } from '@angular/core';
import { NavigationEnd, Router } from '@angular/router';
import { filter } from 'rxjs/operators';
@Injectable()
export class RouteInterceptorService {
private _previousUrl: string;
private _currentUrl: string;
private _routeHistory: string[];
constructor(router: Router) {
this._routeHistory = [];
router.events
.pipe(filter(event => event instanceof NavigationEnd))
.subscribe((event: NavigationEnd) => {
this._setURLs(event);
});
}
private _setURLs(event: NavigationEnd): void {
const tempUrl = this._currentUrl;
this._previousUrl = tempUrl;
this._currentUrl = event.urlAfterRedirects;
this._routeHistory.push(event.urlAfterRedirects);
}
get previousUrl(): string {
return this._previousUrl;
}
get currentUrl(): string {
return this._currentUrl;
}
get routeHistory(): string[] {
return this._routeHistory;
}
}
此外,您还可以在历史记录为空的情况下使用此服务与回退功能
url-back.service.ts
import { Injectable } from '@angular/core';
import { Location } from '@angular/common';
import { Router } from '@angular/router';
const EMPTY_HISTORY_LENGTH = 2;
/**
* This service helps to Navigate back to the prev page, and if no prev page,
* will redirect to the fallback url.
*/
@Injectable()
export class UrlBackService {
constructor(private router: Router, private location: Location) {}
/**
* This method will back you to the previous page,
* if no previous page exists, will redirect you to the fallback url.
* @param href - url, if tryNativeFirst is provided, this is fallback url
* @param tryNativeFirst - try to go back natively using browser history state.
*/
back(href: string, tryNativeFirst: boolean = false) {
if (tryNativeFirst) {
if (history.length === EMPTY_HISTORY_LENGTH) {
this.router.navigate(UrlBackService.urlToArray(href));
} else {
this.location.back();
}
} else {
this.router.navigate(UrlBackService.urlToArray(href));
}
}
/**
* In case that router.navigate method tries to escape all '/' in the string,
* was decided to split string to array, and if URL starts or ends with slash - remove them, eg:
* /my/url will be split to ['', 'my', 'url'], so we need to remove empty spaces use filter function.
* @param href
* @private
*/
private static urlToArray(href: string) {
return href.split('/').filter((notEmpty) => notEmpty);
}
}
url-back.service.spec.ts
import { TestBed } from '@angular/core/testing';
import { UrlBackService } from './url-back.service';
import { Router } from '@angular/router';
import { Location } from '@angular/common';
import { RouterTestingModule } from '@angular/router/testing';
describe('UrlBackService', () => {
let service: UrlBackService;
let router: Router;
let location: Location;
beforeEach(() => {
TestBed.configureTestingModule({
imports: [RouterTestingModule],
providers: [UrlBackService],
});
service = TestBed.inject(UrlBackService);
router = TestBed.inject(Router);
location = TestBed.inject(Location);
});
it('should be created', () => {
expect(service).toBeTruthy();
});
it('no meter what history state is, it should be redirected to the /my/url', () => {
spyOn(router, 'navigate');
service.back('/my/url');
expect(router.navigate).toHaveBeenCalledWith(['my', 'url']);
});
it('in case history is empty push to /my/url', () => {
spyOn(router, 'navigate');
service.back('/my/url', true);
expect(router.navigate).toHaveBeenCalledWith(['my', 'url']);
});
it('in case history is NOT empty push to url1', () => {
spyOn(location, 'back');
window.history.pushState(null, '', 'url1');
service.back('/my/url', true);
expect(location.back).toHaveBeenCalled();
});
});