angularjs复选框验证至少两个

Question

使用AngularJS，我想建立一个验证规则，其中必须至少检查2个复选框才能使输入有效。我试过这个：

<div ng-repeat="item in items">
                            <label><input type="checkbox" ng-model="checked[item.id]" ng-required="!isChecked" />
                            <span>{{item.title}}</span></label>
                          </div>

和

// checkbox validation
    angular.module('app', []).

    run(function($rootScope) {
        $rootScope.items = [
            { id: 1, title: 'Certified Plumber' },
            { id: 2, title: 'Carpentry Experience' },
            { id: 3, title: 'Certified Electrician' },
            { id: 4, title: 'Bartending Experience' },
            { id: 5, title: 'Food Hygiene Certificate' },
            { id: 6, title: 'First Aid Course' },
            { id: 7, title: 'Forklift Drive Certificate' },
            { id: 8, title: "Driver's License (Type B)" }
        ];
        $rootScope.checked = {};
        $rootScope.isChecked = false;
        $rootScope.$watch('checked', function(selected) {
            $rootScope.isChecked = false;
            angular.forEach(selected, function(isChecked) {
                if (isChecked) $rootScope.isChecked = true;
            });
        }, true);
    });

现在，当选中至少一个复选框时，验证工作正常。如何为至少两个复选框自定义它？

Answer 1

如下：

$rootScope.isChecked = false;
    $rootScope.$watch('checked', function(selected) {
        $rootScope.isChecked = false;
        $rootScope.checkedCounter = 0;
        angular.forEach(selected, function(isChecked) {
            if (isChecked) $rootScope.checkedCounter = $rootScope.checkedCounter + 1;
            if($rootScope.checkedCounter >= 2) $rootScope.isChecked = true;
        });
    }, true);