ionic由于使用了header和subheader导致被遮挡的问题的

<ion-nav-bar class="bar-positive"> 
<ion-nav-back-button class="button-icon ion-arrow-left-c"> 
</ion-nav-back-button> 
<h2>helloafds</h2> 
</ion-nav-bar> 
<ion-header-bar class="bar-subheader"> 
<h1>hello</h1> 
</ion-header-bar>

<ion-header-bar align-title="left" class="bar-positive"> 
<div class="buttons"> 
<button class="button" ng-click="doSomething()">Left Button</button> 
</div> 
<h1 class="title">Header</h1> 
<div class="buttons"> 
<button class="button">Right Button</button> 
</div> 
</ion-header-bar> 
<ion-header-bar align-title="left" class="bar-subheader bar-positive"> 
<h1 class="title">Sub Header!</h1> 
</ion-header-bar>