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问题:

Is there any way to check whether the app is running in foreground or background in ionic/cordova/phonegap, I need to use it on android and ios, thanks a lot

回答1:

Use the two Events "Pause" and "Resume". You will find all Events here in the Apache Cordova Events Documentation.

Event - Pause:

The pause event fires when the native platform puts the application into the background, typically when the user switches to a different application.

Event - Resume

The resume event fires when the native platform pulls the application out from the background.

You can add an Eventlistener for that into your code. For those two Events that would be:

Pause - Quick Example

document.addEventListener("pause", onPause, false);

function onPause() {
    // Handle the pause event
}

Or Full Example like this:

<!DOCTYPE html>
<html>
  <head>
    <title>Pause Example</title>

    <script type="text/javascript" charset="utf-8" src="cordova.js"></script>
    <script type="text/javascript" charset="utf-8">

    // Wait for device API libraries to load
    //
    function onLoad() {
        document.addEventListener("deviceready", onDeviceReady, false);
    }

    // device APIs are available
    //
    function onDeviceReady() {
        document.addEventListener("pause", onPause, false);
    }

    // Handle the pause event
    //
    function onPause() {
    }

    </script>
  </head>
  <body onload="onLoad()">
  </body>
</html>

Resume - Quick Example

document.addEventListener("resume", onResume, false);

function onResume() {
    // Handle the resume event
}

Or Full Example like this

<!DOCTYPE html>
<html>
  <head>
    <title>Resume Example</title>

    <script type="text/javascript" charset="utf-8" src="cordova.js"></script>
    <script type="text/javascript" charset="utf-8">

    // Wait for device API libraries to load
    //
    function onLoad() {
        document.addEventListener("deviceready", onDeviceReady, false);
    }

    // device APIs are available
    //
    function onDeviceReady() {
        document.addEventListener("resume", onResume, false);
    }

    // Handle the resume event
    //
    function onResume() {
    }

    </script>
  </head>
  <body onload="onLoad()">
  </body>
</html>

Try that out and let me know, if you need further help!

回答2:

For Ionic 2 and Ionic 3 the solution is:

import { Platform } from 'ionic-angular';

@Component({
  template: `OK`
})

constructor(public platform: Platform) {

    platform.ready().then(() => {

      if (platform.is('cordova')){

        //Subscribe on pause
        this.platform.pause.subscribe(() => {
          //Hello pause
        });

        //Subscribe on resume
        this.platform.resume.subscribe(() => {
          window['paused'] = 0;
        });
       }
    });
}

回答3:

A small service for Ionic based on Sithys answer:

factory('BackgroundCheck', function($ionicPlatform){
    var service = {};
    var inBackground = false;

    $ionicPlatform.ready(function() {        
        document.addEventListener("resume", function(){inBackground = false;}, false);
        document.addEventListener("pause", function(){inBackground = true;}, false);
    });

    service.isActive = function(){
        return inBackground == false;
    }
    return service;    
})

回答4:

Using an angular abstraction of ionic.Platform

//The pause event fires when the native platform puts the application
// into the background, typically when the user switches to a different 
// application.
$ionicPlatform.on('pause', function () {
    // Handle event on pause
});
// The resume event fires when the native platform
//  pulls the application out from the background.
$ionicPlatform.on('resume', function () {
    // Handle event on resume
});

Refer to ionic v1 documentation for $ionicPlatform

回答5:

"Is there any way to check whether the app is running in foreground or background?"

Yes.

1) When an app becomes inactive (runs in the background) Cordova fires the pause event, and when an app becomes active again (brought to the foreground) Cordova fires the resume event.

2) From these events, one can use a variable to store the state as "foreground" or "background".

document.addEventListener("deviceReady", function readyCallback() {


    var isAppInForeground = true;


    document.addEventListener("pause", function pauseCallback() {
      isAppInForeground = false;
    }, false);

    document.addEventListener("resume", function resumeCallback() {
      isAppInForeground = true;
    }, false);

});