最近在学习小程序开发，自己手敲的代码，和教程代码一样（通过工具逐行比对了代码，确保没有敲错代码），是运行效果不一样，不知道问题出在哪里了？恳请大神赐教 [图片] [图片] 我敲的代码： <!--index.wxml--> <view class="box">   <view class='title'>基本绘图</view>   <view>     <canvas canvas-id="myCanvas" ></canvas>   </view>   <view class='btnLayout'>     <button type='primary' bindtap="clear">清除</button>     <button type='primary' bindtap="drawDot">画点</button>     <button type='primary' bindtap="drawCircle">画圆</button>   </view>   <view class='btnLayout'>     <button type='primary' bindtap="drawDash">画虚线</button>     <button type='primary' bindtap="capAndJoin">端点交点</button>     <button type='primary' bindtap="drawText">画字</button>   </view>   <view class='btnLayout'>     <button type='primary' bindtap="circularGrad">圆形渐变</button>     <button type='primary' bindtap="shadowRect">阴影矩形</button>     <button type='primary' bindtap="translucent">半透明</button>   </view> </view> /**index.wxss**/ canvas {   width: 100%;   height: 340px;   background-color: cornflowerblue; } button {   width: 100px; } .btnLayout {   display: flex;   flex-direction: row;   margin: 10px;   justify-content: space-around; } 教材附带的代码： <!--pages/API/Drawing/index.wxml--> <view class="box">   <view class='title'>基本绘图</view>   <view>     <canvas canvas-id="myCanvas" ></canvas>   </view>   <view class='btnLayout'>     <button type='primary' bindtap="clear">清除</button>     <button type='primary' bindtap="drawDot">画点</button>     <button type='primary' bindtap="drawCircle">画圆</button>   </view>   <view class='btnLayout'>     <button type='primary' bindtap="drawDash">画虚线</button>     <button type='primary' bindtap="capAndJoin">端点交点</button>     <button type='primary' bindtap="drawText">画字</button>   </view>   <view class='btnLayout'>     <button type='primary' bindtap="circularGrad">圆形渐变</button>     <button type='primary' bindtap="shadowRect">阴影矩形</button>     <button type='primary' bindtap="translucent">半透明</button>   </view> </view> /* pages/API/Drawing/index.wxss */ canvas {   width: 100%;   height: 340px;   background-color: cornflowerblue; } button {   width: 100px; } .btnLayout {   display: flex;   flex-direction: row;   margin: 10px;   justify-content: space-around; /* 弹性项目沿主轴方向平均分布，两边留有一半的间隔空间。 */ }