效果图：
1.html写上动态padding-bottom
<view class="button-wrap" :style="'padding-bottom:'+bottomPadding+'rpx'"><view class="com-btn cencel-btn">取消</view><view class="com-btn confirm-btn " @click='onConfirmDlg'>确认</view></view>
2.获取设备信息
const res = await uni.getSystemInfo({})
this.bottomPadding = (res.screenHeight - res.safeArea.bottom) * 2 || 30
