addListener

Purpose

Adds a hardware button listener to the list of listeners.

addListener( callback )

This method does not return anything.

Name	Description	Type	Use
callback	Passed to verify the status of a hardware button.	`undefined`	required

The BackAction listener's callback can be structured as follows:

{
    onBackButtonPressed: function() {
        ...
        window.launchbox.BackAction.fireDefaultBackButtonAction();
    }
}

The following table lists all callbacks supported by the listener.

Name	Description	Return type
onBackButtonPressed	Indicates that the "back" hardware button has been pressed.	`undefined`