Calling Default Phonegap Back Button Handler

Question

I have a phonegap app that requires I capture the back button. This works swimmingly but when I am at the main screen and the back button is pressed I want to call the original event handler and let the app close or do whatever comes naturally to the platform with such a press. I know I can tell the app to quit but understand this is bad form for iPhone apps.

No matter what I try (and I have tried many things) I cannot get the original handler to fire. Any advice?

In my code I have a switch statement inside my backbutton event handler that directs the app as needed to the effect of:

switch blahBlah
{
    case 'this' :
        doThis() ;
        break;
    case 'main' :
        // What do I do here that is well behaved for all platforms??? 
        break;
    default:
        doFoo() ;
} 

Answer 1

Detect whenever you land on the main screen and remove your custom event handler.

document.removeEventListener( "backbutton", function(){}, false );

and add the event listener on the other pages (or sections).

document.addEventListener( "backbutton", OverrideBackButton, false );

Hope that helps.

Answer 2

This is what I've used and it seems to work fine for my needs

        function pageinit() {
            document.addEventListener("deviceready", deviceInfo, true);
        }


        function deviceInfo() {
            document.addEventListener("backbutton", onBackButton, true);
        } 

        function onBackButton(e) {
            try{
                var activePage = $.mobile.activePage.attr('id');

                if(activePage == 'Options'){
                    closeOptions();
                } else if(activePage == 'Popup'){
                    closePopup();
                } else if(activePage == 'HomePage'){

                function checkButtonSelection(iValue){
                    if (iValue == 2){
                            navigator.app.exitApp();
                        }
                    }

                e.preventDefault();
                navigator.notification.confirm(
                    "Are you sure you want to EXIT the program?",
                    checkButtonSelection,
                    'EXIT APP:',
                    'Cancel,OK');
                } else {
                     navigator.app.backHistory();
                }
            } catch(e){ console.log('Exception: '+e,3); }
        }

Hope this helps...

Answer 3

Cordova 7.x, at least on Android, doesn't seem to properly update the override state. As a consequence, @SHANK's answer doesn't work anymore.

As a workaround, you can disable back button overriding manually, resulting in default behavior:

navigator.app.overrideBackbutton(false);

To re-active custom handling, analogously do:

navigator.app.overrideBackbutton(true);

I filed a bug report on Apache's issue tracker regarding this.