These are all great solutions, However, if you are currently using Routing then I found this solution to be the easiest and least amount of code needed. Using the 'resolve' property to wait for a promise to complete before triggering the route. e.g.
$routeProvider
.when("/news", {
templateUrl: "newsView.html",
controller: "newsController",
resolve: {
message: function(messageService){
return messageService.getMessage();
}
}
})