//獲取應用實例var app = getApp()var interval;var varName;var ctx = wx.createCanvasContext('canvasArcCir');Page({ data: { }, drawCircle: function () {  clearInterval(varName);  function drawArc(s, e) {   ctx.setFillStyle('white');   ctx.clearRect(0, 0, 200, 200);   ctx.draw();   var x = 100, y = 100, radius = 96;   ctx.setLineWidth(7);   ctx.setStrokeStyle('#BFEFFF');   ctx.setLineCap('round');   ctx.beginPath();   ctx.arc(x, y, radius, s, e, false);   ctx.stroke()   ctx.draw()  }  var step = 1, startAngle = 1.5 * Math.PI, endAngle = 0;  var animation_interval = 1000, n = 60;  var animation = function () {   if (step <= n) {    endAngle = step * 8 * Math.PI / n + 1.5 * Math.PI;    drawArc(startAngle, endAngle);    step++;   } else {    clearInterval(varName);   }  };  varName = setInterval(animation, animation_interval); }, onReady: function () {  //創建并返回繪圖上下文context對象。  var cxt_arc = wx.createCanvasContext('canvasCircle');  cxt_arc.setLineWidth(8);  cxt_arc.setStrokeStyle('#EDEDED');  cxt_arc.setLineCap('round');  cxt_arc.beginPath();  cxt_arc.arc(100, 100, 96, 0, 2 * Math.PI, false);  cxt_arc.stroke();  cxt_arc.draw(); }, onLoad: function (options) { }})

<view class="wrap"> <view class="circle-box">  <canvas class="circle" style="width:200px; height:200px;" canvas-id="canvasArcCir">  </canvas>  <canvas class="circle" style="z-index: -5; width:200px; height:200px;" canvas-id="canvasCircle">  </canvas>  <view class="draw_btn" bindtap="drawCircle">點擊開始</view> </view></view>

page { width: 100%; height: 100%; background-color: #fff;}.circle-box { text-align: center; margin-top: 10vw;}.circle { position: absolute; left: 0; right: 0; margin: auto;}.draw_btn { width: 28vw; position: absolute; top: 31vw; right: 0; left: 0; margin: auto; border: 1px #0D0D0D solid;  background-color: #BFEFFF; border-radius: 5vw;}