Angularjs - Checkbox - count multiple selected/unselected items

how to count the number of selecte/unselected checkbox items using angularjs?

my html

    <label class="col-xs-5  pull-left" style="font-weight: bold; margin-left: 4px; margin-top: -17px;" >You have choose <font size="3" color="green"></font> Customer(s)</label>

<tr ng-repeat="item in $data " >
             <td width="30" style="text-align: left" header="\'smsChkbx\'">
           <label>
            <input type="checkbox" class="ace" name="someList[]" value="" ng-model="checkboxes.items[item.somename]" />

checkbox function

 $scope.$watch('checkboxes.items', function(values) {
                        if (!$scope.mydata) {
                            return;
                        }
                        var checked = 0,
                            unchecked = 0,
                            total = $scope.mydata.length;
                        angular.forEach($scope.mydata, function(item) {
                            checked += ($scope.checkboxesSms.items[item.somename]) || 0;
                            unchecked += (!$scope.checkboxesSms.items[item.somename]) || 0;
                        });
                        if ((unchecked == 0) || (checked == 0)) {
                            $scope.checkboxes.checked = (checked == total);
                        }

                        **if(checked != 0 && unchecked != 0){
                            $scope.checkedResult++;
                        }**                    
                        $scope.tableParamsSms.reload();                                                
                         console.log($scope.checkedResult);
                        console.log((checked != 0 && unchecked != 0));
                        angular.element(document.getElementById("select_Sms")).prop("indeterminate", (checked != 0 && unchecked != 0));
                    }, true); 

counts properly when i check for first time, the issue is it wlll also count when i uncheck the checked one

also want to count when its checked by multiple check option