How do I disable Android Back button on one page and change to exit button on every other page

Asked 9/10, 2012 at 0:32 Answered 18/4, 2016 at 14:24

android cordova jquery-mobile back-button-control

I am developing an Android application using Phonegap that interacts with my Drupal site. I have re-assigned the Android "Back" button to prompt the user to log off from the Drupal server however, I just want it disabled on the login page (for obvious reasons). I can get it to work but only until the user logs out then once on the login page the button remains re-assigned as a logoff button. Here's the code I have so far:

   <head>
         <script>
        /* Wait until device is ready to re-assign Back button */
        document.addEventListener("deviceready", onDeviceReady, false);
        function onDeviceReady() {
            document.addEventListener("backbutton", onBackKeyPress, false);
        }
        function onBackKeyPress() {
            /* If the current page is the login page, disable the button completely (aka do nothing) */
            if ($.mobile.activePage.attr('id') == 'login_page') {
            }

            /* Else, execute log off code */
            else {
                if (confirm("Are you sure you want to logout?")) {
                    /* Here is where my AJAX code for logging off goes */
                }
                else {
                    return false;
                }
            }
        }
        </script>
</head>

The problem is that the Back button doesn't get re-assigned. I cannot figure out a way to re-run the above code when the user logs out and ends up back on the login page.

If anybody is willing to provide a solution for this I will be very grateful!

Autotransformer answered 9/10, 2012 at 0:32 Comment(0)

deviceready is important. If not used, sometimes you can get blocking Back button, sometimes not. Often in debug it works, in production no.

document.addEventListener("deviceready", onDeviceReady, false);
    function onDeviceReady() {
        document.addEventListener("backbutton", function (e) {
            e.preventDefault();
        }, false );
}

EDIT 2013-11-03 Common mistake is that development is performed on desktop and cordova script is excluded. One then forgets to include the cordova script for the mobile version.

Cloudlet answered 27/8, 2013 at 12:29 Comment(1)

Works for me PhoneGap 2.7 – Bifilar 8/10, 2013 at 2:29

Try this:

document.addEventListener("backbutton", function(e){
    if($.mobile.activePage.is('#login_page')){
        e.preventDefault();
    }
    else {
        if (confirm("Are you sure you want to logout?")) {
            /* Here is where my AJAX code for logging off goes */
        }
        else {
            return false;
        }
    }
}, false);

Giguere answered 26/12, 2012 at 15:56 Comment(1)

doing this in my project, seems to be running only once, so it enters the if sentence, prevent the default execution of the back button and leaves, then the back button is not functional in any page on the app – Belvabelvedere 2/9, 2016 at 18:54

document.addEventListener("deviceready", onDeviceReady, false);
function onDeviceReady() {
    document.addEventListener("backbutton", function (e) {
        e.preventDefault();
    }, false );
}

Pinhole answered 13/12, 2013 at 12:45 Comment(0)

You have to override back button action in device ready... here is a full working example "index.html"

<!DOCTYPE html>
<html>
  <head>
    <title>Back Button</title>
    <link rel="stylesheet" type="tex`enter code here`t/css" href="style.css">
    <script>
        function getTitle() {
            document.getElementById("ct").innerHTML = "DEMO: " + document.title;
        }
    </script>
    <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);
        getTitle();
    }
    // device APIs are available
    //
    function onDeviceReady() {
        // Register the event listener
        document.addEventListener("backbutton", onBackKeyDown, false);
    }
    // Handle the back button
    //
    function onBackKeyDown() {
        alert('Backbutton key pressed');
        console.log('Backbutton key pressed');
    }
    </script>
  </head>
  <body onload="onLoad()">
  <ul id="nav">
        <li><a href="index.html">&larr; Back</a></li>
        <li><a href="#" id="ct" onclick="location.reload();"></a></li>
    </ul>
  </body>
</html>

I used this code and back button is overridden finally....

Ref--> https://github.com/amirudin/PhoneGapPluginDemo/blob/master/www/evt-backbutton.html

Timothee answered 18/4, 2016 at 14:24 Comment(0)

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