ionic框架中，想在顶部标题栏右侧增加图标按钮，怎么写？

<ion-nav-bar class="bar-stable" animation="slide-left-right">
    <ion-nav-back-button class="button-clear">
        <i class="ion-ios-arrow-left"></i>
        <!--标题-->
    </ion-nav-back-button>

</ion-nav-bar>


<ion-nav-view>
    <!--内容-->
</ion-nav-view>

<ion-tabs class="tabs-icon-top tabs-stable tabs-color-active-balanced {{hideTabs}}">
    <ion-tab title="首页" icon-on="ion-ios-home" icon-off="ion-ios-home-outline" ui-sref="tab.home">
        <ion-nav-view animation="slide-left-right" name="tab-home"></ion-nav-view>
    </ion-tab>
    <ion-tab title="订单" icon-on="ion-ios-list" icon-off="ion-ios-list-outline" ui-sref="tab.order">
        <ion-nav-view animation="slide-left-right" name="tab-order"></ion-nav-view>
    </ion-tab>
</ion-tabs>

//*//

<ion-view view-title="全部订单">
    <ion-content class="padding">
       
     <h2><a ng-href="#/tab/state">order</a></h2>

    </ion-content>
</ion-view>

---

应该是：
<ion-tab>

<ion-nav-bar>
    <ion-nav-buttons side="right">
        <button></button>
    </ion-nav-buttons>
</ion-nav-bar>

</ion-tab>