registerBackButtonAction can`t work

ionic-v1
1

$ionicPlatform.registerBackButtonAction(function (event) {
event.preventDefault();
event.stopPropagation();
alert(123456);
},1);

i add crosswallk ,please help me

2

try to increase priority to 100.

3

i have try edit it to 100 but still dont work

4

i’m having the same problem, have you found out what was wrong?