<table class="txt_logged" ng-controller="mainCtrl" ng-show="{{userdetails}}">

.controller('mainCtrl',['$scope','SharedService',function($scope,SharedService)
{
    $scope.userdetails=SharedService.getUserDetails();

    $scope.$watch(function(){ return SharedService.getUserDetails()}, function(newValue, oldValue)
    {
        if (newValue && newValue !== oldValue)
        {
            var t= SharedService.getUserDetails();
            if(t.toString()=="true")
            {
                $scope.userdetails =true;
            }
            else
            {
                $scope.userdetails =false;
            }

        }
    });

 }]);

<table class="txt_logged" ng-controller="mainCtrl" ng-show="userdetails">