[英]How to call a method from another component after view is fully loaded (AppComponent)?
I'm using MatMenu from Angular Material inside HeaderComponent
. 我正在HeaderComponent
内的Angular Material中使用MatMenu。 I just need to open the Menu under certain conditions (method), calling this method on ProductDetailComponent
. 我只需要在某些条件(方法)下打开菜单,然后在ProductDetailComponent
上调用此方法即可。 However this method only works inside ngAfterViewInit()
, after the view is loaded. 但是,此方法仅在加载视图之后在ngAfterViewInit()
内部ngAfterViewInit()
。
I found a way to comunicate from ProductDetailComponent
to HeaderComponent
, however there is a Children-Parent relationship to reach the components. 我找到了一种从ProductDetailComponent
到HeaderComponent
进行通信的方法,但是有一个Children-Parent关系可以到达这些组件。 HeaderComponent
is called from AppComponent
. HeaderComponent
从AppComponent
。
Here is AppComponent 这是AppComponent
<my-header [openMenu]="clickBehavior"></my-header> <router-outlet></router-outlet> <!-- ProductComponent -->
ProductComponent ProductComponent
<router-outlet></router-outlet> <!-- ProductDetailComponent -->
ProductDetail component ProductDetail组件
export class ProductComponent { clickBehavior = new BehaviorSubject(null); click() { this.clickBehavior.next(1); } }
ProductDetail markup ProductDetail标记
<!-- i need to move it to app component <my-header [openMenu]="clickBehavior"></my-header> --> <div> <button (click)="click()">Click</button> </div>
Header component 标头组件
export class HeaderComponent implements AfterViewInit { @ViewChild('trigger') trigger: MatMenuTrigger; @Input() openMenu: Observable<any>; ngAfterViewInit() { this.openMenu.subscribe(value => { if (value) { this.trigger.openMenu(); } }); } }
Header markup 标头标记
<button mat-button [matMenuTriggerFor]="menu" #trigger="matMenuTrigger">Menu </button> <mat-menu #menu="matMenu"> <button mat-menu-item>Item 1</button> <button mat-menu-item>Item 2</button> </mat-menu>
You can achieve this by using a shared service and injecting the service where it is required. 您可以通过使用共享服务并在需要的地方注入服务来实现。
Setup a shared service, i put methods to get, set and toggle the menu state. 设置共享服务,我将方法设置为获取,设置和切换菜单状态。
SharedService.ts SharedService.ts
import { Injectable } from '@angular/core';
@Injectable()
export class SharedService {
//The current menu state
private showMenu_ = false;
//get the current menu state
get showMenu() {
return showMenu_;
}
//set the menu state
set showMenu(state: boolean) {
this.showMenu_ = state;
}
//toggle the menu
public toggleMenu() {
this.showMenu_ = !this.showMenu;
}
}
Inject the service into appComponent so we can control the menu state with it. 将服务注入到appComponent中,以便我们可以使用它控制菜单状态。
appComponent.ts appComponent.ts
import { SharedService } from 'PATH TO SHARED SERVICE';
...
constructor(public sharedService: SharedService){}
Set my-header to show/hide based on the state set in the sharedService. 根据sharedService中设置的状态将my-header设置为显示/隐藏。
appComponent.html appComponent.html
<my-header *ngIf="sharedService.showMenu"></my-header>
Inject the service into any other component/page to change the state of the menu. 将服务注入任何其他组件/页面以更改菜单的状态。 In this case ProductComponent.ts. 在这种情况下为ProductComponent.ts。
ProductComponent.ts ProductComponent.ts
import { SharedService } from 'PATH TO SHARED SERVICE';
...
constructor(public sharedService: SharedService){}
ProductComponent.html ProductComponent.html
<div>
<button (click)="sharedService.toggleMenu()">Click</button>
</div>
Or with BehavourSubject from service. 或与BehavourSubject脱离服务。
Create the BehaviorSubject in SharedService. 在SharedService中创建BehaviorSubject。
import { Injectable } from '@angular/core';
@Injectable()
export class SharedService {
//The current menu state
private showMenu_ = false;
private showMenu$: BehaviorSubject<boolean> = new
BehaviorSubject(false);
//get a reference to showMenu$ for subscription
public menuState() {
return showMenu$;
}
//Change menu state to show.
public showMenu(){
this.showMenu_ = true;
this.showMenu$.next(this.showMenu_);
}
//Change menu state to hide.
public hideMenu(){
this.showMenu_ = false;
this.showMenu$.next(this.showMenu_);
}
//Toggle menu state.
public toggleMenu(){
this.showMenu_ = !this.showMenu;
this.ShowMenu$.next(this.showMenu_);
}
//get the current menu state.
public getMenuState() {
return this.showMenu$.getValue();
}
Inject the service into appComponent so we can subscribe to the menu state. 将服务注入appComponent,以便我们可以订阅菜单状态。
appComponent.ts appComponent.ts
import { SharedService } from 'PATH TO SHARED SERVICE';
...
export class appComponent implements OnInit, OnDestroy {
//variable used to show/hide the menu.
public showMenu;
//reference to subscription so we can unsubscribe later.
private this.menuStateSub: Subscription;
constructor(public sharedService: SharedService){}
ngOnInit() {
//subscribe to the menuState BehaviorSubject
this.menuStateSub = this.sharedService.menuState().subscribe((state)=>{
this.showMenu = state;
})
}
ngOnDestroy() {
//unsubscribe before leaving the page
this.menuStateSub.unsubscribe();
}
Set my-header to show/hide based on the state set in the sharedService. 根据sharedService中设置的状态将my-header设置为显示/隐藏。
appComponent.html appComponent.html
<my-header *ngIf="sharedService.showMenu"></my-header>
Finally inject the service where we need to control the menu state. 最后,将服务注入我们需要控制菜单状态的位置。
ProductComponent.ts ProductComponent.ts
import { SharedService } from 'PATH TO SHARED SERVICE';
...
constructor(public sharedService: SharedService){}
and now we can use the service to toggle the state. 现在我们可以使用该服务来切换状态。 ProductComponent.html ProductComponent.html
<div>
<button (click)="sharedService.toggleMenu()">Click</button>
</div>
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