Ionic framework 离子3背景模式返回为假

我使用Ionic 3，我希望我的应用程序也能在后台工作，现在我尝试在app.component中使用Ionic 3的后台模式，使用这个.backgroundMode.enable（），然后使用方法isEnable（），但当我使用isEnable（）时，它返回为false。我做错了什么，为什么它返回为假？请帮帮我

import { BackgroundMode } from '@ionic-native/background-mode';
import { Component } from '@angular/core';
import { Platform } from 'ionic-angular';
import { StatusBar } from '@ionic-native/status-bar';
import { SplashScreen } from '@ionic-native/splash-screen';
import { HomePage } from '../pages/home/home';

@Component({
  templateUrl: 'app.html'
})

export class MyApp {
  rootPage: any = HomePage;

  constructor(platform: Platform, statusBar: StatusBar, splashScreen: SplashScreen, private backgroundMode: BackgroundMode) {
    platform.ready().then(() => {

      this.backgroundMode.enable()
      var bgmStatus = this.backgroundMode.isEnabled();
      console.log(bgmStatus);

      statusBar.styleDefault();
      splashScreen.hide();
    });
  }
}

   

    import { BackgroundMode } from '@ionic-native/background-mode';
    import { Component } from '@angular/core';
    import { Platform } from 'ionic-angular';
    import { StatusBar } from '@ionic-native/status-bar';
    import { SplashScreen } from '@ionic-native/splash-screen';
    import { HomePage } from '../pages/home/home';
    
    @Component({
      templateUrl: 'app.html'
    })
    
    export class MyApp {
      rootPage: any = HomePage;
    
      constructor(platform: Platform, statusBar: StatusBar, splashScreen: SplashScreen, private backgroundMode: BackgroundMode) {
        platform.ready().then(() => {
    
          this.backgroundMode.enable()
          var bgmStatus = this.backgroundMode.isEnabled();
          console.log(bgmStatus);
    
          statusBar.styleDefault();
          splashScreen.hide();
        });
      }
    }