设置tab中的icon为自定义图标的方法

// html
<ion-tabs class="tabs-icon-top tabs-color-active-positive">

  <!-- 首页 -->
  <ion-tab title="首页" icon-off="tab-home2" icon-on="tab-home1" href="#/tab/home">
    <ion-nav-view name="tab-home"></ion-nav-view>
  </ion-tab>

  <!-- 商城 -->
  <ion-tab title="换券" icon-off="tab-home3" icon-on="tab-home4" href="#/tab/exchange">
    <ion-nav-view name="tab-exchange"></ion-nav-view>
  </ion-tab>

   <!-- 视频 -->
   <ion-tab title="充值" icon-off="tab-home5" icon-on="tab-home6" href="#/tab/recharge">
    <ion-nav-view name="tab-recharge"></ion-nav-view>
  </ion-tab>

  <!-- 我的 -->
  <ion-tab title="我的" icon-off="tab-home7" icon-on="tab-home8" href="#/tab/account">
    <ion-nav-view name="tab-account"></ion-nav-view>
  </ion-tab>
</ion-tabs>


// css
.tab-home1 {
  background:url(../img/tab1.png) no-repeat center;
  background-size: contain;
}
.tab-home2 {
  background:url(../img/tab2.png) no-repeat center;
  background-size: contain;
}
....