angular radio repeat 默认选中值

html代码如下：

<ul>
  <li ng-repeat="thing in favoriteThings">
    <input type="radio" ng-value="thing" ng-model="selected" name="stuff"/>
      {{thing.text}}
  </li>
</ul>

js代码如下：

$scope.favoriteThings = [
    {nr: 1, text: "Raindrops on roses"},
    {nr: 2, text: "Whiskers on kittens"},
    {nr: 3, text: "Bright copper kettles"},
    {nr: 4, text: "Warm woolen mittens"},
    {nr: 5, text: "Brown paper packages tied up with strings"},
    {nr: 6, text: "Cream colored ponies"},
    {nr: 7, text: "Crisp apple streudels"},
    {nr: 8, text: "Doorbells"},
    {nr: 9, text: "Sleigh bells"},
    {nr: 10, text: "Schnitzel with noodles"},
    {nr: 11, text: "Wild geese that fly with the moon on their wings"},
    {nr: 12, text: "Girls in white dresses with blue satin sashes"},
    {nr: 13, text: "Snowflakes that stay on my nose and eyelashes"},
    {nr: 14, text: "Silver white winters that melt into springs"}
  ];
  
  $scope.selected = {nr: 1, text: "Raindrops on roses"};

目前我这样做，不能默认选中一个值，也不知道问题出在哪里。

我想页面一加载就默认选中一个值，其中每一项的值类型是对象，我应该如何做？

---

需要设置ng-model的默认值
如:

  $scope.selected = $scope.favoriteThings[0];

将会默认选择这一项。

不能使用

  $scope.selected = {nr: 1, text: "Raindrops on roses"};

因为ng-model中对于Object只有相同的引用才会认为两者相等，上述做法新建一个对象，与repeat中的value不等

---

可在 ng-repeat 中使用 ng-checked , 举个栗子：

<label ng-repeat="(key, val) in genders track by $index">
    <input type="radio" name="gender" value="{{key}}" ng-checked="list.gender==key">{{val}}
</label>