真机调试(iPhone XR)时，<view>组件的 touchstart touchmove touchend事件无响应，但是在微信开发者工具（nightly v1.02.1912062）中的模拟器上是可以触发响应的。

<view class="echart_panel" bindtouchstart="touchStart" bindtouchmove="touchMove" bindtouchend="touchEnd">

        <ec-canvas  id="mychart" canvas-id="mychart-bar"  ec="{{ ec }}"></ec-canvas>

        <view class="bottombtn">

                <button type="primary" bindtap="previous">往前</button>

                <button type="primary" bindtap="next">往后</button>

        </view>

</view>