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?
你可以在你的路由类上实现routerOnActivate()方法,它会提供之前路由的信息。
routerOnActivate(nextInstruction: ComponentInstruction, prevInstruction: ComponentInstruction) : any
然后你可以使用router.navigateByUrl()并传递ComponentInstruction生成的数据。例如:
this._router.navigateByUrl(prevInstruction.urlPath);
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Angular 2的最终版本中。X / 4。x -这里是文档https://angular.io/api/common/Location
/* typescript */
import { Location } from '@angular/common';
// import stuff here
@Component({
// declare component here
})
export class MyComponent {
// inject location into component constructor
constructor(private location: Location) { }
cancel() {
this.location.back(); // <-- go back to previous location on cancel
}
}
我这样做的方式,而导航到不同的页面添加一个查询参数通过传递当前位置
this.router.navigate(["user/edit"], { queryParams: { returnUrl: this.router.url }
读取组件中的这个查询参数
this.router.queryParams.subscribe((params) => {
this.returnUrl = params.returnUrl;
});
如果returnUrl存在,则启用后退按钮,当用户单击后退按钮时
this.router.navigateByUrl(this.returnUrl); // Hint taken from Sasxa
这应该能够导航到前一页。而不是使用位置。我觉得上面的方法是更安全的考虑情况下,用户直接登陆到你的页面,如果他按后退按钮的位置。回到它将重定向用户到前一页,这将不是你的网页。
在angular 4中使用preserveQueryParams,例如:
url: /list?page=1
<a [routerLink]="['edit',id]" [preserveQueryParams]="true"></a>
当点击链接时,您将被重定向编辑/10?Page =1,保留参数
裁判:https://angular.io/docs/ts/latest/guide/router.html # !# link-parameters-array
也为我工作时,我需要移动回文件系统。 P.S. @angular: "^5.0.0"
<button type="button" class="btn btn-primary" routerLink="../">Back</button>
我做了一个按钮,我可以在我的应用程序的任何地方重复使用。
创建这个组件
import { Location } from '@angular/common';
import { Component, Input } from '@angular/core';
@Component({
selector: 'back-button',
template: `<button mat-button (click)="goBack()" [color]="color">Back</button>`,
})
export class BackButtonComponent {
@Input()color: string;
constructor(private location: Location) { }
goBack() {
this.location.back();
}
}
然后在需要后退按钮时将其添加到任何模板中。
<back-button color="primary"></back-button>
注意:这里使用的是Angular材质,如果你不使用这个库,那么移除垫子按钮和颜色。
用Angular 5.2.9测试过
如果你使用锚而不是按钮,你必须使用href="javascript:void(0)"将其设置为被动链接,以使Angular Location正常工作。
app.component.ts
import { Component } from '@angular/core';
import { Location } from '@angular/common';
@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: [ './app.component.css' ]
})
export class AppComponent {
constructor( private location: Location ) {
}
goBack() {
// window.history.back();
this.location.back();
console.log( 'goBack()...' );
}
}
app.component.html
<!-- anchor must be a passive link -->
<a href="javascript:void(0)" (click)="goBack()">
<-Back
</a>
<按钮返回按钮>返回</button>
你可以把它放到一个指令中,这个指令可以附加到任何可点击的元素上:
import { Directive, HostListener } from '@angular/core';
import { Location } from '@angular/common';
@Directive({
selector: '[backButton]'
})
export class BackButtonDirective {
constructor(private location: Location) { }
@HostListener('click')
onClick() {
this.location.back();
}
}
用法:
<button backButton>BACK</button>
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;
}
}
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>
是的,你能做到。在你的typescript组件上编写这段代码,然后享受吧!
import { Location } from '@angular/common'
import { Component, Input } from '@angular/core'
@Component({
selector: 'return_page',
template: `<button mat-button (click)="onReturn()">Back</button>`,
})
export class ReturnPageComponent {
constructor(private location: Location) { }
onReturn() {
this.location.back();
}
}
也许你想检查之前的历史点是否在你的应用程序中。例如,如果你直接进入你的应用程序并执行location.back()(例如,通过按下工具栏中的<- back按钮),你会回到浏览器的主页面,而不是去应用程序中的其他地方。
这是我检查这个的方法:
import { Component } from '@angular/core';
import { ActivatedRoute, Router } from '@angular/router';
import { Location } from '@angular/common';
@Component({
selector: 'app-foo',
template: ''
})
export class FooComponent {
private readonly canGoBack: boolean;
constructor(
private readonly route: ActivatedRoute,
private readonly router: Router,
private readonly location: Location
) {
// This is where the check is done. Make sure to do this
// here in the constructor, otherwise `getCurrentNavigation()`
// will return null.
this.canGoBack = !!(this.router.getCurrentNavigation()?.previousNavigation);
}
goBack(): void {
if (this.canGoBack) {
// We can safely go back to the previous location as
// we know it's within our app.
this.location.back();
} else {
// There's no previous navigation.
// Here we decide where to go. For example, let's say the
// upper level is the index page, so we go up one level.
this.router.navigate(['..'], {relativeTo: this.route});
}
}
}
我们检查加载当前路由的导航是否有前一个兄弟。这必须在导航过程仍处于活动状态时在构造函数中完成。
但也有一些注意事项:
即使之前的位置实际上在我们的应用程序中,但页面被刷新,canGoBack也将为false。 用户可能想通过点击浏览器的返回按钮“返回”到上一页(goBack()发生的地方),但由于应用程序返回历史而不是按一个新的位置,用户将会返回得更远,可能会感到困惑。
我是这么说的:
import { Location } from '@angular/common'
import { Component, Input } from '@angular/core'
@Component({
selector: 'Back_page',
template: `<button (click)="onBack()">Back</button>`,
})
export class BackPageComponent {
constructor(private location: Location) { }
onBack() {
this.location.back();// <-- go back to previous location
}
}
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();
});
});
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();
}
2022 利用你的应用程序路由-更多的是一种“角度方法”,而不是访问浏览器的位置对象来获取导航历史。 想想你为什么需要用户返回,以及“返回”在应用程序及其路由的更广泛的上下文中意味着什么。
例如,从子路由返回到父路由
this.router.navigate(['..'], {relativeTo: this.route});
您还可以阅读以前的导航
previousNavigation:先前成功的导航对象。只有 一个先前的导航是可用的,因此这个先前的 Navigation对象的previousNavigation为空值。
这是我想出来的,你也可以查一下是否有上一页。 确保在你的appComponent中使用了这个服务。
import { Injectable } from '@angular/core';
import { Location } from '@angular/common';
import { NavigationEnd, Router } from '@angular/router';
interface HistoryData {
previousPage: string | null,
currentPage: string | null,
}
@Injectable({ providedIn: 'root' })
export class GoBackService {
private historyData: HistoryData = { previousPage: null, currentPage: null };
constructor(private router: Router, private location: Location) {
this.router.events.subscribe((event) => {
if (event instanceof NavigationEnd) {
this.historyData.previousPage = this.historyData.currentPage;
this.historyData.currentPage = event.urlAfterRedirects;
}
});
}
public goBack(): void {
if (this.historyData.previousPage) this.location.back();
}
public canGoBack(): boolean {
return Boolean(this.historyData.previousPage);
}
}
只需使用Location,这是一个Angular服务,应用程序可以使用它与浏览器的URL进行交互。
导入:
import { Location } from '@angular/common';
注射:
constructor(private location: Location) { }
简单地使用它:
goBack() {
this.location.back(); // Navigates back in the platform's history
}
检测到的未更改组件的@Parziphal答案版本:
import { Location } from '@angular/common';
import { Router } from '@angular/router';
constructor(private readonly router: Router, private readonly location: Location) {
location.onUrlChange(() => this.canGoBack = !!this.router.getCurrentNavigation()?.previousNavigation);
}
goBack(): void {
if (this.canGoBack) {
this.location.back();
}
}
进口:
import { Location } from '@angular/common';
import { Router } from '@angular/router';
构造函数:
constructor(private readonly router: Router, private readonly location: Location) {
location.onUrlChange(() => this.canGoBack = !!this.router.getCurrentNavigation()?.previousNavigation);
}
可选,避免返回到应用程序之外:
private canGoBack: boolean = false;
constructor(private router:Router,private location:Location){
this.canGoBack = !!(this.router.getCurrentNavigation()?.previousNavigation);
}
返回:
goBack(): void {
if (this.canGoBack) {
this.location.back();
}
}
Html:
<button (click)="goBack()"></button>