在 Angular 2 中，您可以 订阅 (Rx 事件) 到 Router 实例。

因此，您可以执行以下操作：

class MyClass {
  constructor(private router: Router) {
    router.subscribe((val) => /*whatever*/)
  }
}

自 rc.1 起：

class MyClass {
  constructor(private router: Router) {
    router.changes.subscribe((val) => /*whatever*/)
  }
}

自 2.0.0 起：

另请参阅： Router.events doc

class MyClass {
  constructor(private router: Router) {
    router.events.subscribe((val) => {
        // see also 
        console.log(val instanceof NavigationEnd) 
    });
  }
}

RxJS 6

router.events.pipe(filter(event => event instanceof NavigationStart))

感谢 Peilonrayz（见下面的评论）

新路由器 >= RC.3

import { Router, NavigationStart, NavigationEnd, NavigationError, NavigationCancel, RoutesRecognized } from '@angular/router';

constructor(router:Router) {
  router.events.forEach((event) => {
    if(event instanceof NavigationStart) {
    }
    // NavigationEnd
    // NavigationCancel
    // NavigationError
    // RoutesRecognized
  });
}

您还可以通过给定的事件进行过滤：

import 'rxjs/add/operator/filter';

constructor(router:Router) {
  router.events
    .filter(event => event instanceof NavigationStart)
    .subscribe((event:NavigationStart) => {
      // You only receive NavigationStart events
    });
}

使用 pairwise 运算符 来获取前一个和当前事件也是一个不错的主意。 https://github.com/angular/angular/issues/11268#issuecomment-244601977

import 'rxjs/add/operator/pairwise';
import { Router } from '@angular/router';

export class AppComponent {
    constructor(private router: Router) {
        this.router.events.pairwise().subscribe((event) => {
            console.log(event);
        });
    };
}

对于 Angular 7 ，应该这样写：

this.router.events.subscribe((event: Event) => {})

详细示例如下：

import { Component } from '@angular/core'; 
import { Router, Event, NavigationStart, NavigationEnd, NavigationError } from '@angular/router';

@Component({
    selector: 'app-root',
    template: `<router-outlet></router-outlet>`
})
export class AppComponent {

    constructor(private router: Router) {

        this.router.events.subscribe((event: Event) => {
            if (event instanceof NavigationStart) {
                // Show loading indicator
            }

            if (event instanceof NavigationEnd) {
                // Hide loading indicator
            }

            if (event instanceof NavigationError) {
                // Hide loading indicator

                // Present error to user
                console.log(event.error);
            }
        });

   }
}