AngularJS - $index not updated with keyPress - angularjs

Question

I'm pretty new in AngularJS so this might be easy to solve,
I have a list of meetings I'm trying to navigate between them with my keyboard using keyPress,
The problem is that after the first navigation (UP or DOWN) using the keyboard, the $index is not updating, so for instance if I'm on meeting number 4, and clicking on the "UP" key, I will navigate to meeting 3, but clicking 'DOWN' afterwards will navigate me to meeting number 5 (and not back to 4, becuase my $index is stuck at 4)
the HTML looks like this:
<ul class="meeting-list">
<div ng-repeat="meeting in meetings" ng-init="meeting.innerIndex = $index">
<div class="meeting-block" ng-keydown="KeyPress($event, $index)" ng-click="showMeeting(meeting)" >
<span class="title">{{meeting.Title}}</span><br/>
</div>
</div>
</ul>
This is my JS code:
$scope.meetings = [{"title":"sub1","id":123},{"id":124,"title":"sub2"},{"title":"sub3","id":125},{"title":"sub4","id":126}];
$scope.KeyPress = function(keypress, index) {
if (keypress.which == 38) { //UP
if (index != 0) {
for (var i = 0; i < $scope.meetings.length; i++) {
if ($scope.meetings[i].innerIndex == (index - 1)){
$scope.showMeeting($scope.meetings[i]);
return ;
}
}
}
if (keypress.which = 40) { //DOWN
if ($scope.meetings.length - 1 != index) {
for (var i = 0; i < $scope.meetings.length; i++) {
if ($scope.meetings[i].innerIndex == (index + 1)) {
$scope.showMeeting($scope.meetings[i]);
return ;
}
}
}
};
$scope.showMeeting = function(meeting) {
$location.path('meetings/view/' + meeting.Id);
};

Answer 1

$index is a property of an ng-repeated item, it is always equal to the position in the ng-reapeated array. I am not sure if it's implemented to be unassignable, but I expect it should be and you should treat it that way.
Instead of trying to change the index, you should have your own property that keeps track of the index in the array that you're selected on.
This is trivial to do, just initialise it in your controller, then use it instead of your $index when navigating.
$scope.selectedIndex = 0; //start with the first meeting selected.

Answer 2

You have 2 problems here.
You cannot use the $index to navigate up and down the list
When you do index -= 1; this as no effect whatsoever on the $index or the selected meeting. You are passing the $index's value (an immutable number) and not it's reference. So, if you have $index = 5 and do index -= 1 (on the KeyPress), you will end up with: $index = 5 and index = 4.
You need to change the focus of the selected meeting in order to update the element that will receive the keyboard event
In order to change the focus you could use something like this:
// UP
$(keypress.target).prev().trigger('focus');
...
// DOWN
$(keypress.target).next().trigger('focus');
But I'm not sure if it's a 100% applicable to your case. You may need to define another way to select the element that will receive the focus. A directive here would be a good idea...