ember-cordova-events

Summary

ember-cordova-events provides access to Cordova events, allowing your ember app to react to device level events such as offline, low battery, menu button, and more.

There are two mechanisms to handle these events:

  • Evented: All events are available for subscription from inside a function, e.g. lifecycle hooks like init or beforeModel, via Ember.Evented; and
  • Subscribe: The subscribe util is a function that will tear down your listeners and prevent memory leaks. Like the computed helper, you register it at the top-level of your file, declare your service property + event, and pass it a function that should fire.

These are not interchangeable; subscribe relies on the this scope available on the object, while Evented relies on the this scope inside a function. Whenever possible, we endorse the use of Subscribe vs. Evented.

Installation

ember install ember-cordova-events

Example Usage

Show an alert when the battery is low, using both forms (demonstration only!!!):

import Ember from 'ember';
import subscribe from 'ember-cordova-events/utils/subscribe';

const {
  Route,
  inject: { service }
} = Ember;

export default Route.extend({
  cordovaEvents: service('ember-cordova/events'),

  onBatteryLow: subscribe('cordovaEvents.batterylow', function() {
    this._alertBattery();
  }),

  beforeModel() {
    this.get('cordovaEvents').on('batterylow', this, '_alertBattery');
  },

  deactivate() {
    this.get('cordovaEvents').off('batterylow', this, '_alertBattery');
  },

  _alertBattery() {
    alert('Battery level is low!');
  }
});

Supported Events

from https://cordova.apache.org/docs/en/latest/cordova/events/events.html

const CORDOVA_EVENTS = new A([
  'deviceready',
  'pause',
  'resume',
  'backbutton',
  'menubutton',
  'searchbutton',
  'startcallbutton',
  'endcallbutton',
  'volumedownbutton',
  'volumeupbutton',
  'batterycritical',
  'batterylow',
  'batterystatus',
  'online',
  'offline'
]);

Usage

Subscribe

This method will tear down your object’s listeners automatically, but can only be used at the top-level of an Ember object (just like Ember.computed and Ember.on).

Subscribe will fail when placed in functions; for those cases, you will want to use Evented.

Example usage:

import Ember from 'ember';
import subscribe from 'ember-cordova-events/utils/subscribe';

const {
  Route,
  inject: { service }
} = Ember;

export default Route.extend({
  cordovaEvents: service('ember-cordova/events'),

  logReady: subscribe('cordovaEvents.deviceready', function() {
    console.log('ready');
  })
});

The following will fail, because the subscribe util is not top-level on the object. Use Evented instead.

  beforeModel() {
    // this will not fire, use Events instead
    subscribe('cordovaEvents.deviceready', function() {
      console.log('will never be ready');
    });
  }
Evented

Use the standard Ember.Evented syntax when you want to create listeners inside of a function (e.g. beforeModel). You will need to manually unsubscribe listeners to avoid leaky behaviour.

Example usage:

export default Route.extend({
  cordovaEvents: service('ember-cordova/events'),

  activate: function() {
    if (this.shouldNotListen) { return; }

    this.get('cordovaEvents').on('pause', this, '_resumeListening');
  },

  deactivate: function() {
    this.get('cordovaEvents').off('pause', this, '_resumeListening');
  },

  _resumeListening: function() {
    console.log("i'm listening to what you have to say");
  }
});