Check/ Uncheck All checkboxes - AngularJS ng-repeat

问题

I have a structure which looks like this: http://jsfiddle.net/deeptechtons/TKVH6/

<div>
<ul ng-controller="checkboxController">
    <li>Check All
        <input type="checkbox" ng-model="selectedAll" ng-click="checkAll()" />
    </li>
    <li ng-repeat="item in Items">
        <label>{{item.Name}}
            <input type="checkbox" ng-model="item.Selected" />
        </label>
    </li>
</ul>
</div>

angular.module("CheckAllModule", [])
.controller("checkboxController", function checkboxController($scope) {


$scope.Items = [{
    Name: "Item one"
}, {
    Name: "Item two"
}, {
    Name: "Item three"
}];
$scope.checkAll = function () {
    if ($scope.selectedAll) {
        $scope.selectedAll = true;
    } else {
        $scope.selectedAll = false;
    }
    angular.forEach($scope.Items, function (item) {
        item.Selected = $scope.selectedAll;
    });

};


});

When check all is selected or deselected, all other checkboxes are selected. But when "Check All" is selected, and I deselect one of the items, I want "Check All" to be deselected.

Thanks in advance!

(PS: Thanks to deeptechtons for the JSFiddle)

回答1:

If you are using Angular 1.3+ you can use getterSetter from ng-model-options to solve this and avoid manually keeping track of the allSelected state

HTML:

<input type="checkbox" ng-model="allSelected" ng-model-options="{getterSetter: true}"/>

JS:

var getAllSelected = function () {
    var selectedItems = $scope.Items.filter(function (item) {
        return item.Selected;
    });

    return selectedItems.length === $scope.Items.length;
}

var setAllSelected = function (value) {
    angular.forEach($scope.Items, function (item) {
        item.Selected = value;
    });
}

$scope.allSelected = function (value) {
    if (value !== undefined) {
        return setAllSelected(value);
    } else {
        return getAllSelected();
    }
}

http://jsfiddle.net/2jm6x4co/

回答2:

You can use this function to check if all records are checked whenever a checkbox changes:

$scope.checkStatus= function() {
            var checkCount = 0;
            angular.forEach($scope.Items, function(item) {
                 if(item.Selected) checkCount++;
            });
                $scope.selectedAll = ( checkCount === $scope.Items.length);
        };

The view code:

<input type="checkbox" ng-model="item.Selected" ng-change="checkStatus();"/>

http://jsfiddle.net/TKVH6/840/

回答3:

working example: http://jsfiddle.net/egrendon/TKVH6/845/

view:

<input type="checkbox" ng-model="item.Selected" ng-click="setCheckAll(item)" />

controller:

angular.module("CheckAllModule", [])
    .controller("checkboxController", function checkboxController($scope) {


    $scope.Items = [{
        Name: "Item one"
    }, {
        Name: "Item two"
    }, {
        Name: "Item three"
    }];
    $scope.checkAll = function () {
        if ($scope.selectedAll) {
            $scope.selectedAll = true;
        } else {
            $scope.selectedAll = false;
        }
        angular.forEach($scope.Items, function (item) {
            item.Selected = $scope.selectedAll;
        });

    };

    $scope.setCheckAll = function (item) {
        //
        // Check if checkAll should be unchecked
        //
        if ($scope.selectedAll && !item.Selected) {
            $scope.selectedAll = false;
        } 
        //
        // Check if all are checked.
        //
        var checkCount = 0;
        angular.forEach($scope.Items, function(item) {
            if(item.Selected) checkCount++;
        });
        $scope.selectedAll = ( checkCount === $scope.Items.length);
    };

});

回答4:

Here is a neat little way of doing this

http://jsfiddle.net/TKVH6/850/

Use a little bit of undescore (just the reduce) and ng-checked

  <input type="checkbox" ng-model="selectedAll" ng-click="checkAll()" ng-checked="allSelected()"/>


   $scope.allSelected = function () {
      var allSelect = _.reduce($scope.Items, function (memo, todo) {
          return memo + (todo.Selected ? 1 : 0);
        }, 0);
      return (allSelect === $scope.Items.length);
  };

You could use javascripts built in .reduce if you did not want to use underscore.

回答5:

This answer has similar logic to Kmart2k1's answer. It puts the responsibility of updating the master checkbox on each child in the ng-repeat. Instead of using array.forEach, I use array.some to more quickly check if any of the items are unselected.

HTML:

<li ng-repeat="item in Items">
    <label>{{item.Name}}
        <input type="checkbox" ng-model="item.Selected" ng-change="notifyMaster()"/>
    </label>
</li>

Javascript

$scope.notifyMaster = function () {
    $scope.selectedAll = !$scope.Items.some(function (item) {
       return !item.Selected;  //check if ANY are unchecked
    });
}

Forked fiddle

来源：https://stackoverflow.com/questions/31010373/check-uncheck-all-checkboxes-angularjs-ng-repeat