angularjs 默认选中ng-repeat的一个

HTML：

<ul class="face-moni-list">
        <li ng-repeat = "camera in CameraList" ng-click="searchCamera(camera.cameraId)"
            ng-class="{false:'defaultClass',true:'activeClass'}[choseIndex==camera.cameraId]">
            <i class="fa fa-video-camera"></i> {{camera.cameraName}}</li>
    </ul>

CSS：

.moni-left .face-moni-list li:hover {
    border: 1px solid #1682c3 !important;
}
.moni-left .face-moni-list li.defaultClass {
    background: #fff;
    color: #666;
}
.moni-left .face-moni-list li.activeClass {
    background: #7abce4;
    color: #fff;
}

JS：

$scope.searchCamera={};
        $scope.CameraList = {};
        $scope.choseIndex = "";  //申明一个参数
        /*$http.post($scope.URL+ 'camera/getCameraList', $scope.searchCamera).success(function(data) {
            $scope.CameraList = data.data.list;
        });*/
        $http.get("json/camera.json").success(function(data) {
            $scope.CameraList = data.data;
            $scope.choseIndex = $scope.CameraList[0].cameraId;   //给参数默认赋值数组的第一个
        });

$scope.searchCamera = function(cameraId){
            $scope.choseIndex = cameraId;
        }