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。


当前回答

我采取的另一种方法是

import {Component, OnInit} from '@angular/core';
import {fromEvent} from "rxjs";
import {debounceTime, map, startWith} from "rxjs/operators";


function windowSizeObserver(dTime = 300) {
  return fromEvent(window, 'resize').pipe(
    debounceTime(dTime),
    map(event => {
      const window = event.target as Window;

      return {width: window.innerWidth, height: window.innerHeight}
    }),
    startWith({width: window.innerWidth, height: window.innerHeight})
  );
}

@Component({
  selector: 'app-root',
  template: `
    <h2>Window Size</h2>
    <div>
      <span>Height: {{(windowSize$ | async)?.height}}</span>
      <span>Width: {{(windowSize$ | async)?.width}}</span>
    </div>
  `
})
export class WindowSizeTestComponent {
  windowSize$ = windowSizeObserver();
}

这里的windowSizeObserver可以在任何组件中重用

其他回答

基于@cgatian的解决方案,我建议简化如下:

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',
      e => this.onResize$.emit({
        width: e.target.innerWidth,
        height: e.target.innerHeight
      }));
  }
}

用法:

import { Component } from '@angular/core';
import { ResizeService } from './resize-service';

@Component({
  selector: 'my-component',
  template: `{{ rs.onResize$ | async | json }}`
})
export class MyComponent {
  constructor(private rs: ResizeService) { }
}
<div (window:resize)="onResize($event)"
onResize(event) {
  event.target.innerWidth;
}

或者使用HostListener装饰器:

@HostListener('window:resize', ['$event'])
onResize(event) {
  event.target.innerWidth;
}

支持的全局目标有window、document和body。

在https://github.com/angular/angular/issues/13248在Angular中实现之前,强制订阅DOM事件并使用RXJS来减少事件的数量(如其他一些答案所示)会更好地提高性能。

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

这并不是问题的确切答案,但它可以帮助那些需要检测任何元素的大小变化的人。

我已经创建了一个库,可以将调整大小的事件添加到任何元素中——Angular Resize event。

它内部使用resizsensor从CSS元素查询。

示例使用

HTML

<div (resized)="onResized($event)"></div>

打印稿

@Component({...})
class MyComponent {
  width: number;
  height: number;

  onResized(event: ResizedEvent): void {
    this.width = event.newWidth;
    this.height = event.newHeight;
  }
}

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 >