angular怎么修改ng-repeat的ng-checked状态？

从后端获取数组如下：

$scope.arr = [
    {
        selected:true;
    }
    {
        selected:true;
    }
    {
        selected:true;
    }
]
$scope.select = function(){
    // 如何在不调用后端接口的情况下，修改ng-repeat中ng-checked的状态实现全选和反选？
    
}

<ul>
    <li ng-repeat="i in arr">
        <input type="checkbox" ng-checked="i.selected">
    </li>
</ul>

<input type="checkbox" ng-click="select()">

---

$scope.arr = [
    { selected:true }
    { selected:true }
    { selected:true }
];

$scope.select = function(status){
    $scope.arr.map(function(item){
        item.selected = status === 'all'? true: !item.selected;
    });
}

<ul>
    <li ng-repeat="i in arr">
        <input type="checkbox" ng-checked="i.selected">
    </li>
</ul>

<button ng-click="select('all')">全选</button>
<button ng-click="select('inverse')">反选</button>

这里边的反选说的是在不全选的情况下，选中变为未选中，未选中变选中，不是清空！！！
清空的话要复杂一点。

---

http://stackoverflow.com/questions/12648466/how-can-i-get-angular-js-checkboxes-with-select-unselect-all-functionality-and-i

---

$scope.selectedAll = true;

$scope.arr = [
    {
        selected:true;
    }
    {
        selected:true;
    }
    {
        selected:true;
    }
]
$scope.select = function(){
    $scope.selectedAll = !$scope.selectedAll;
    $scope.arr.forEach(function(item){
        item.selected = $scope.selectedAll;
    });
};