我想执行一些基于窗口重新大小事件(在加载和动态)的任务。
目前我的DOM如下:
<div id="Harbour">
<div id="Port" (window:resize)="onResize($event)" >
<router-outlet></router-outlet>
</div>
</div>
事件正确触发
export class AppComponent {
onResize(event) {
console.log(event);
}
}
我如何从这个事件对象检索宽度和高度?
谢谢。
我写这个库是为了找到Angular中组件边界大小改变(重新调整大小)的方法,希望能帮助到其他人。你可以把它放在根组件上,会做和窗口大小调整一样的事情。
步骤1:导入模块
import { BoundSensorModule } from 'angular-bound-sensor';
@NgModule({
(...)
imports: [
BoundSensorModule,
],
})
export class AppModule { }
步骤2:添加如下指令
<简单的组件boundSensor > < /简单的组件>
步骤3:接收边界大小的详细信息
import { HostListener } from '@angular/core';
@Component({
selector: 'simple-component'
(...)
})
class SimpleComponent {
@HostListener('resize', ['$event'])
onResize(event) {
console.log(event.detail);
}
}
如果你想在调整大小完成后只发生一个事件,最好使用RxJS和debounceTime:
debounceTime:丢弃输出间隔时间少于指定时间的发出值。
在运行代码之前,他在两个事件之间等待> 0.5s。
简单地说,它在执行下一个代码之前等待大小调整完成。
// RxJS v6+
import { fromEvent } from 'rxjs';
import { debounceTime, map } from 'rxjs/operators';
...
const resize$ = fromEvent(window, 'resize');
resize$
.pipe(
map((i: any) => i),
debounceTime(500) // He waits > 0.5s between 2 events emitted before running the next.
)
.subscribe((event) => {
console.log('resize is finished');
});
堆栈闪电战
我检查了大部分答案。然后决定查看关于布局的Angular文档。
Angular有自己的观察者来检测不同的大小,而且很容易实现到组件或服务中。
一个简单的例子是:
import {BreakpointObserver, Breakpoints} from '@angular/cdk/layout';
@ component({…})
类MyComponent {
构造函数(breakpointObserver: breakpointObserver) {
breakpointObserver.observe ([
断点。HandsetLandscape,
断点。HandsetPortrait
])。订阅(result => {
If (result.matches) {
this.activateHandsetLayout ();
}
});
}
}
希望能有所帮助
这里有一个更好的方法。根据Birowsky的回答。
步骤1:用RxJS observable创建一个angular服务。
import { Injectable } from '@angular/core';
import { Observable, BehaviorSubject } from 'rxjs';
@Injectable()
export class WindowService {
height$: Observable<number>;
//create more Observables as and when needed for various properties
hello: string = "Hello";
constructor() {
let windowSize$ = new BehaviorSubject(getWindowSize());
this.height$ = (windowSize$.pluck('height') as Observable<number>).distinctUntilChanged();
Observable.fromEvent(window, 'resize')
.map(getWindowSize)
.subscribe(windowSize$);
}
}
function getWindowSize() {
return {
height: window.innerHeight
//you can sense other parameters here
};
};
步骤2:注入上述服务,并订阅在服务中创建的任何可观察对象,无论您希望在哪里接收窗口大小调整事件。
import { Component } from '@angular/core';
//import service
import { WindowService } from '../Services/window.service';
@Component({
selector: 'pm-app',
templateUrl: './componentTemplates/app.component.html',
providers: [WindowService]
})
export class AppComponent {
constructor(private windowService: WindowService) {
//subscribe to the window resize event
windowService.height$.subscribe((value:any) => {
//Do whatever you want with the value.
//You can also subscribe to other observables of the service
});
}
}
充分理解响应式编程总是有助于克服困难的问题。希望这能帮助到一些人。
我所做的就像Johannes Hoppe建议的那样:
import { EventManager } from '@angular/platform-browser';
import { Injectable, EventEmitter } from '@angular/core';
@Injectable()
export class ResizeService {
public onResize$ = new EventEmitter<{ width: number; height: number; }>();
constructor(eventManager: EventManager) {
eventManager.addGlobalEventListener('window', 'resize',
event => this.onResize$.emit({
width: event.target.innerWidth,
height: event.target.innerHeight
}));
}
getWindowSize(){
this.onResize$.emit({
width: window.innerWidth,
height: window.innerHeight
});
}
}
在app.component.ts:
Import { ResizeService } from ".shared/services/resize.service"
import { Component } from "@angular/core"
@Component({
selector: "app-root",
templateUrl: "./app.component.html",
styleUrls: ["./app.component.css"]
})
export class AppComponent{
windowSize: {width: number, height: number};
constructor(private resizeService: ResizeService){
}
ngOnInit(){
this.resizeService.onResize$.subscribe((value) => {
this.windowSize = value;
});
this.resizeService.getWindowSize();
}
}
然后在你的app.component.html中:
<router-outlet *ngIf = "windowSize? "宽度> 1280 && windowSize?。高度> 700;errorComponent”>
< / router-outlet >
< ng-template # errorComponent >
< app-error-component > < / app-error-component >
< / ng-template >
正确的方法是利用EventManager类来绑定事件。这让你的代码可以在其他平台上工作,例如使用Angular Universal进行服务器端渲染。
import { EventManager } from '@angular/platform-browser';
import { Observable } from 'rxjs/Observable';
import { Subject } from 'rxjs/Subject';
import { Injectable } from '@angular/core';
@Injectable()
export class ResizeService {
get onResize$(): Observable<Window> {
return this.resizeSubject.asObservable();
}
private resizeSubject: Subject<Window>;
constructor(private eventManager: EventManager) {
this.resizeSubject = new Subject();
this.eventManager.addGlobalEventListener('window', 'resize', this.onResize.bind(this));
}
private onResize(event: UIEvent) {
this.resizeSubject.next(<Window>event.target);
}
}
在组件中使用这个服务非常简单,只需将这个服务作为提供者添加到app.module中,然后在组件的构造函数中导入它。
import { Component, OnInit } from '@angular/core';
@Component({
selector: 'my-component',
template: ``,
styles: [``]
})
export class MyComponent implements OnInit {
private resizeSubscription: Subscription;
constructor(private resizeService: ResizeService) { }
ngOnInit() {
this.resizeSubscription = this.resizeService.onResize$
.subscribe(size => console.log(size));
}
ngOnDestroy() {
if (this.resizeSubscription) {
this.resizeSubscription.unsubscribe();
}
}
}