ios 刘海屏怎么设置？

uni-app 为 iOS（iPhoneX）底部安全区适配：http://ask.dcloud.net.cn/article/35564

已解决 头部样式加这个。。height: env(safe-area-inset-top);
但是要区分苹果和安卓的。
<template>
<view class="status_bar" :style="{height:platform=='ios'?'env(safe-area-inset-top)':statusBarHeight} ">
<view class="top_view" :style="{height:platform=='ios'?'env(safe-area-inset-top)':statusBarHeight} "></view>
</view>
</template>

<script>
export default {
data: {
statusBarHeight: '' ,
platform:''
},
created() {
let _t = this;
setTimeout(() => { //获取状态栏高度，setTimeout后才能调用uni.
uni.getSystemInfo({
success: function(res) {
_t.statusBarHeight = res.statusBarHeight;
_t.platform= res.platform;
}
});
}, 1);
}
};
</script>
<stype>
.status_bar {
height: var(--status-bar-height);
width: 100%;
background: #fff;
}

.top_view {  
    height: var(--status-bar-height);  
    width: 100%;  
    position: fixed;  
    top: 0;  
    z-index: 9;  
    background: #fff;  
}  

</stype>