Javascript 在路由解析程序/路由更改上显示加载图标

我试图显示一个加载图标，而路由解析器从数据库获取数据

我尝试了以下选项：

_router.events.subscribe((routerEvent: RouterEvent) => {

   if (routerEvent instanceof NavigationStart) {
      console.log("start");
      this.loading = true;

   } else if (routerEvent instanceof NavigationError || NavigationCancel || NavigationEnd) {
    console.log("end");
    this.loading = false;
  }

});

<h1 *ngIf="loading">Loading</h1>

<div class="uk-offcanvas-content">
  <h1>{{loading}}</h1>
  <h1 *ngIf="loading">Loading</h1>

  <app-root-nav></app-root-nav>

  <app-notifications></app-notifications>

  <router-outlet></router-outlet> 
</div>

import {Component, OnInit, AfterViewInit} from '@angular/core';
import {AuthenticationService} from "../../authentication/services/authentication.service";
import {Router, Event, NavigationStart, NavigationEnd, NavigationCancel, NavigationError} from "@angular/router";

import {RouterEvent} from "@angular/router";
import UIkit from 'uikit'

@Component({
   selector: 'app-root',
   templateUrl: './app.component.html',
   styleUrls: ['./app.component.css']
 })

 export class AppComponent implements OnInit, AfterViewInit {

  isLoggedIn: boolean;
  public loading: boolean = true;
  UIkit: any;

  constructor(private _router: Router, private _authService: AuthenticationService) {

  _router.events.subscribe((routerEvent: RouterEvent) => {
    if (routerEvent instanceof NavigationStart) {

      this.loading = true;
      console.log(routerEvent);
      console.log("Loading is " + this.loading);

  } else if (routerEvent instanceof NavigationError || NavigationCancel || NavigationEnd) {

    this.loading = false;
  }
});
}

ngAfterViewInit() {
}

ngOnInit() {

  UIkit.notification({
    message: 'my-message!',
    status: 'primary',
    pos: 'top-right',
    timeout: 5000
  });

 }

}

根组件：

_router.events.subscribe((routerEvent: RouterEvent) => {

   if (routerEvent instanceof NavigationStart) {
      console.log("start");
      this.loading = true;

   } else if (routerEvent instanceof NavigationError || NavigationCancel || NavigationEnd) {
    console.log("end");
    this.loading = false;
  }

});

<h1 *ngIf="loading">Loading</h1>

<div class="uk-offcanvas-content">
  <h1>{{loading}}</h1>
  <h1 *ngIf="loading">Loading</h1>

  <app-root-nav></app-root-nav>

  <app-notifications></app-notifications>

  <router-outlet></router-outlet> 
</div>

import {Component, OnInit, AfterViewInit} from '@angular/core';
import {AuthenticationService} from "../../authentication/services/authentication.service";
import {Router, Event, NavigationStart, NavigationEnd, NavigationCancel, NavigationError} from "@angular/router";

import {RouterEvent} from "@angular/router";
import UIkit from 'uikit'

@Component({
   selector: 'app-root',
   templateUrl: './app.component.html',
   styleUrls: ['./app.component.css']
 })

 export class AppComponent implements OnInit, AfterViewInit {

  isLoggedIn: boolean;
  public loading: boolean = true;
  UIkit: any;

  constructor(private _router: Router, private _authService: AuthenticationService) {

  _router.events.subscribe((routerEvent: RouterEvent) => {
    if (routerEvent instanceof NavigationStart) {

      this.loading = true;
      console.log(routerEvent);
      console.log("Loading is " + this.loading);

  } else if (routerEvent instanceof NavigationError || NavigationCancel || NavigationEnd) {

    this.loading = false;
  }
});
}

ngAfterViewInit() {
}

ngOnInit() {

  UIkit.notification({
    message: 'my-message!',
    status: 'primary',
    pos: 'top-right',
    timeout: 5000
  });

 }

}

根组件HTML:

_router.events.subscribe((routerEvent: RouterEvent) => {

   if (routerEvent instanceof NavigationStart) {
      console.log("start");
      this.loading = true;

   } else if (routerEvent instanceof NavigationError || NavigationCancel || NavigationEnd) {
    console.log("end");
    this.loading = false;
  }

});

<h1 *ngIf="loading">Loading</h1>

<div class="uk-offcanvas-content">
  <h1>{{loading}}</h1>
  <h1 *ngIf="loading">Loading</h1>

  <app-root-nav></app-root-nav>

  <app-notifications></app-notifications>

  <router-outlet></router-outlet> 
</div>

import {Component, OnInit, AfterViewInit} from '@angular/core';
import {AuthenticationService} from "../../authentication/services/authentication.service";
import {Router, Event, NavigationStart, NavigationEnd, NavigationCancel, NavigationError} from "@angular/router";

import {RouterEvent} from "@angular/router";
import UIkit from 'uikit'

@Component({
   selector: 'app-root',
   templateUrl: './app.component.html',
   styleUrls: ['./app.component.css']
 })

 export class AppComponent implements OnInit, AfterViewInit {

  isLoggedIn: boolean;
  public loading: boolean = true;
  UIkit: any;

  constructor(private _router: Router, private _authService: AuthenticationService) {

  _router.events.subscribe((routerEvent: RouterEvent) => {
    if (routerEvent instanceof NavigationStart) {

      this.loading = true;
      console.log(routerEvent);
      console.log("Loading is " + this.loading);

  } else if (routerEvent instanceof NavigationError || NavigationCancel || NavigationEnd) {

    this.loading = false;
  }
});
}

ngAfterViewInit() {
}

ngOnInit() {

  UIkit.notification({
    message: 'my-message!',
    status: 'primary',
    pos: 'top-right',
    timeout: 5000
  });

 }

}

更新2:

_router.events.subscribe((routerEvent: RouterEvent) => {

   if (routerEvent instanceof NavigationStart) {
      console.log("start");
      this.loading = true;

   } else if (routerEvent instanceof NavigationError || NavigationCancel || NavigationEnd) {
    console.log("end");
    this.loading = false;
  }

});

<h1 *ngIf="loading">Loading</h1>

<div class="uk-offcanvas-content">
  <h1>{{loading}}</h1>
  <h1 *ngIf="loading">Loading</h1>

  <app-root-nav></app-root-nav>

  <app-notifications></app-notifications>

  <router-outlet></router-outlet> 
</div>

import {Component, OnInit, AfterViewInit} from '@angular/core';
import {AuthenticationService} from "../../authentication/services/authentication.service";
import {Router, Event, NavigationStart, NavigationEnd, NavigationCancel, NavigationError} from "@angular/router";

import {RouterEvent} from "@angular/router";
import UIkit from 'uikit'

@Component({
   selector: 'app-root',
   templateUrl: './app.component.html',
   styleUrls: ['./app.component.css']
 })

 export class AppComponent implements OnInit, AfterViewInit {

  isLoggedIn: boolean;
  public loading: boolean = true;
  UIkit: any;

  constructor(private _router: Router, private _authService: AuthenticationService) {

  _router.events.subscribe((routerEvent: RouterEvent) => {
    if (routerEvent instanceof NavigationStart) {

      this.loading = true;
      console.log(routerEvent);
      console.log("Loading is " + this.loading);

  } else if (routerEvent instanceof NavigationError || NavigationCancel || NavigationEnd) {

    this.loading = false;
  }
});
}

ngAfterViewInit() {
}

ngOnInit() {

  UIkit.notification({
    message: 'my-message!',
    status: 'primary',
    pos: 'top-right',
    timeout: 5000
  });

 }

}

app.component.html:

_router.events.subscribe((routerEvent: RouterEvent) => {

   if (routerEvent instanceof NavigationStart) {
      console.log("start");
      this.loading = true;

   } else if (routerEvent instanceof NavigationError || NavigationCancel || NavigationEnd) {
    console.log("end");
    this.loading = false;
  }

});

<h1 *ngIf="loading">Loading</h1>

<div class="uk-offcanvas-content">
  <h1>{{loading}}</h1>
  <h1 *ngIf="loading">Loading</h1>

  <app-root-nav></app-root-nav>

  <app-notifications></app-notifications>

  <router-outlet></router-outlet> 
</div>

import {Component, OnInit, AfterViewInit} from '@angular/core';
import {AuthenticationService} from "../../authentication/services/authentication.service";
import {Router, Event, NavigationStart, NavigationEnd, NavigationCancel, NavigationError} from "@angular/router";

import {RouterEvent} from "@angular/router";
import UIkit from 'uikit'

@Component({
   selector: 'app-root',
   templateUrl: './app.component.html',
   styleUrls: ['./app.component.css']
 })

 export class AppComponent implements OnInit, AfterViewInit {

  isLoggedIn: boolean;
  public loading: boolean = true;
  UIkit: any;

  constructor(private _router: Router, private _authService: AuthenticationService) {

  _router.events.subscribe((routerEvent: RouterEvent) => {
    if (routerEvent instanceof NavigationStart) {

      this.loading = true;
      console.log(routerEvent);
      console.log("Loading is " + this.loading);

  } else if (routerEvent instanceof NavigationError || NavigationCancel || NavigationEnd) {

    this.loading = false;
  }
});
}

ngAfterViewInit() {
}

ngOnInit() {

  UIkit.notification({
    message: 'my-message!',
    status: 'primary',
    pos: 'top-right',
    timeout: 5000
  });

 }

}

---

当路由解析程序从数据库获取数据时，请尝试此代码以显示加载图标：

 constructor(private router: Router){
          router.events.subscribe(e => {
                if (e instanceof ChildActivationStart) {
                      this.loaderservice.show();
                 } else if (e instanceof ChildActivationEnd) {
                      this.loaderservice.hide();
                  }
         });
    }

---

我也有类似的情况，我通过以下方式解决：

  public loading = true;

  constructor(private router: Router) {

  }

  public onClick(): void {
    this.loading = true;
    this.router.navigate(['/test']).then(_ => {
      this.loading = false;
    });
  }

---

我以编程方式管理导航。在开始导航之前，我将加载变量设置为

true

，当路由完成时，我将其值切换为

false

。

这里的问题非常简单，但很容易忽略。您正在不正确地检查路由器事件类型，它应该如下所示：

else if (routerEvent instanceof NavigationError || routerEvent instanceof NavigationCancel || routerEvent instanceof NavigationEnd)

您使用的方法是始终返回true，因为您的第二个子句基本上是“or if NavigationCancel is truthy”，这是一个定义，因为它是一个现有类型。因此，当路由解析开始时，加载会立即设置为false，因为在NavigationEnd事件之前有很多中间路由器事件，并且由于您检查的方式，所有这些事件都会设置为false

---

plunk:

您是否可以初始化

公共加载：boolean=true

，而不是在

导航开始

中将其设置为

true

？另一个建议是：将

loading

设置为属性，并将

console.log（“loading is”，value）

放入setter中，以查看其值是否在适当的时候发生了更改。还有一个建议：在回调开始时放置

console.log（routerEvent）

，查看您是否捕获了所有适当的事件。@ConnorsFan感谢您的评论。我已经应用了你提供的建议。不幸的是仍然没有运气。有关更多详细信息，请参阅我更新的问题。我猜您的本地服务器响应数据太快。试着人为地减慢速度，将.delay（3000）放在可观察到的分辨率中。@bryan60仍然不走运，我的朋友。我刚试过你的建议。这真让我受不了，真不敢相信我居然错过了。有时是简单的事情让你发疯。谢谢你的帮助，伙计。非常感谢。p、 因为某种原因，我必须等3个小时才能颁发奖金。我很快就会做的。这是事实，已经发生在我身上无数次了，这一次真的很容易被忽视，4-5个开发人员一开始就错过了，包括我。我甚至没有意识到这一点，直到我开始在plunkr中记录所有将loading设置为false的路由器事件，并意识到除start之外的所有路由器事件都将其设置为false，然后检查子句，它击中了我。很乐意帮忙。