微信小程序：实时圆形进度条实现

 
 
  开始动态绘制

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: 35vw;  position: absolute;  top: 33vw;  right: 0;  left: 0;  margin: auto;  border: 1px #000 solid;  border-radius: 5vw;
}

//获取应用实例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(5);
    ctx.setStrokeStyle('#d81e06');
    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 * 2 * Math.PI / n + 1.5 * Math.PI;
      drawArc(startAngle, endAngle);
      step++;
    } else {
      clearInterval(varName);
    }
  };
  varName = setInterval(animation, animation_interval);
},  onReady: function () {    //创建并返回绘图上下文context对象。
  var cxt_arc = wx.createCanvasContext('canvasCircle');
  cxt_arc.setLineWidth(6);
  cxt_arc.setStrokeStyle('#eaeaea');
  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) {

}
})