弹出 fixed 弹窗后，在弹窗上滑动会导致下层的页面一起跟着滚动。
解决方法：
在弹出层加上 catchtouchmove 事件
示例代码：
<view class="modal-view" hidden="{{!showModal}}" bindtap="toggleModal" catchtouchmove="preventTouchMove">
<view class="modal">
<view class="modal-item" catchtap="makePhoneCall">{{site.phone}}</view>
<view class="modal-item" catchtap="toggleModal">取消</view>
</view>
</view>
Pages({
preventTouchMove() {}
})
还有一种方法如下：给catchtouchmove="ture"
<view class="modal-view" hidden="{{!showModal}}" bindtap="toggleModal" catchtouchmove="ture">
<view class="modal">
<view class="modal-item" catchtap="makePhoneCall">{{site.phone}}</view>
<view class="modal-item" catchtap="toggleModal">取消</view>
</view>
</view>