前言

进度条展示操作的当前进度，进度条使用场景：

• 在操作需要较长时间才能完成时，为用户显示该操作的当前进度和状态。
• 当一个操作会打断当前界面，或者需要在后台运行，且耗时可能超过 2 秒时；
• 当需要显示一个操作完成的百分比时。

小程序进度条属性介绍：

一、progress进度条详解

1.普通进度条

<view class="progress-box">
  <progress percent="20" show-info stroke-width="3"/>
</view>

<view class="progress-box">
  <progress percent="40" active stroke-width="3" />
  <icon class="progress-cancel" type="cancel"></icon>
</view>

<view class="progress-box">
  <progress percent="60" active stroke-width="3" />
</view>

<view class="progress-box">
  <progress percent="80" color="#10AEFF" active stroke-width="3" />
</view>

2.异步进度条

<view class="gap">代码示例,单击模拟网络异步</view>
<progress show-info bindtap="onTapProgressBar" stroke-width="2" percent="{{percentValue}}" backgroundColor="#f2f2f2" active-mode="forwards" active bindactiveend="onProgressActiveEnd"/>

onTapProgressBar(e){
  console.log(e)
  let progress = this.data.percentValue
  if (progress < 100){
    progress += 5
    this.setData({percentValue:Math.min(100, progress)})
  }
},

3.圆角进度条

<view class="gap">progress已产生的进度条如何设置圆角？</view>
<progress border-radius="5" percent="20" show-info />

4.进度条的重新加载

<view class="gap">已经加载完的进度条progress，怎么点击某个按钮让它重新加载呢？</view>
<progress bindtap="onTapProgressBar" stroke-width="2" percent="{{percentValue}}" active-mode="forwards" active show-info="{{false}}" bindactiveend="onProgressActiveEnd"/>
<button bindtap="onTapReloadBtn">重新加载</button>

onTapReloadBtn(e){
  this.setData({percentValue:0})
  this.setData({percentValue:50})
},

5.环形进度条

5.1 自定义组件的封装

1、组件的封装

<view class='canvasBox'>
<!-- 外部灰色的圆  -->
  <view class='bigCircle'></view>
  <!-- 内部白色的圆 -->
  <view class='littleCircle'></view>
  <canvas type="2d" id="runCanvas" class='canvas'></canvas>
</view>

.canvasBox{
  height: 500rpx;
  position: relative;
  background-color: white;
}
/* 外部灰色的圆 */
.bigCircle{
  width: 420rpx;
  height: 420rpx;
  border-radius: 50%;
  position: absolute;
  top:0;
  bottom: 0;
  left: 0;
  right: 0;
  margin: auto auto;
  background-color: #f2f2f2;
}
/* 内部白色的圆 */
.littleCircle{
  width: 350rpx;
  height: 350rpx;
  border-radius: 50%;
  position: absolute;
  top:0;
  bottom: 0;
  left: 0;
  right: 0;
  margin: auto auto;
  background-color: white;
}
.canvas{
  width: 420rpx;
  height: 420rpx;
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  right: 0;
  margin: auto auto;
  z-index: 99;
}

Component({
  runTimerid:0,
  behaviors: [],
  properties: {
    percent: {
      type: Number,
      value: 0,
      observer: function (newVal, oldVal) {
        this.draw(newVal);
      }
    },
  },
  data: {
    percentage: '', //百分比
    animTime: '', // 动画执行时间
  }, // 私有数据，可用于模版渲染

  lifetimes: {
    // 生命周期函数，可以为函数，或一个在methods段中定义的方法名
    attached: function () { },
    moved: function () { },
    detached: function () { },
  },

  // 生命周期函数，可以为函数，或一个在methods段中定义的方法名
  attached: function () { }, // 此处attached的声明会被lifetimes字段中的声明覆盖

  pageLifetimes: {
    // 组件所在页面的生命周期函数
    show: function () { },
  },
  created() { },

  ready() {
    if (this.data.percent) this.draw(this.data.percent);
  },

  methods: {
    // 绘制圆形进度条方法
    run(c, w, h) {
      let that = this;
      var num = (2 * Math.PI / 100 * c) - 0.5 * Math.PI;
      that.ctx2.arc(w, h, w - 8, -0.5 * Math.PI, num)
      that.ctx2.setStrokeStyle("#09bb07");//绿色
      that.ctx2.setLineWidth("16");
      that.ctx2.setLineCap("butt");
      that.ctx2.stroke();

      that.ctx2.beginPath();
      that.ctx2.setFontSize(40); //注意不要加引号
      that.ctx2.setFillStyle("#b2b2b2");//浅灰色字体
      that.ctx2.setTextAlign("center");
      that.ctx2.setTextBaseline("middle");
      that.ctx2.fillText(c + "%", w, h);
      that.ctx2.draw();
    },
    // 动画效果实现
    canvasTap(start, end, time, w, h) {
      let that = this;
      start++;
      if (start > end) {
        return false;
      }
      that.run(start, w, h);
      
      that.runTimerid = setTimeout(function () {
        that.canvasTap(start, end, time, w, h);
      }, time);
    },

    draw(percent) {
      const id = 'runCanvas'
      const animTime = 500
      if (percent > 100) return
      if (!this.ctx2) {
        const ctx2 = wx.createCanvasContext(id, this)
        this.ctx2 = ctx2
      }

      let oldPercentValue = this.data.percentage
      this.setData({
        percentage: percent,
        animTime: animTime
      });
      var time = this.data.animTime / (this.data.percentage-oldPercentValue);

      const query = wx.createSelectorQuery().in(this)
      query.select('#' + id).boundingClientRect((res) => {
        var w = parseInt(res.width / 2);
        var h = parseInt(res.height / 2);
        if (this.runTimerid) clearTimeout(this.runTimerid)
        this.canvasTap(oldPercentValue, percent, time, w, h)
      }).exec()
    }
  }
})

2、组件的使用

{
  "usingComponents": {
    "circle-progress": "../circle-progress/index"
  }
}

<view class="gap">环形进度条</view>
<circle-progress id="progress1" percent="{{percentValue}}" />
<button bindtap="drawProgress">redraw</button>

drawProgress(){
  if (this.data.percentValue >= 100){
    this.setData({
      percentValue:0
    })
  }
  this.setData({
    percentValue:this.data.percentValue+10
  })
}

5.2 第三方环形进度条组件

1、使用第三方组件，在项目根目录下执行命令：

npm install mp-progress --save

在需要使用的页面中配置新增mp-progress的组件定义：

"usingComponents": {
  "mpProgress": "mp-progress/dist/component/mp-progress"
}

在页面data中定义对应的数据，config参数的使用方法和之前api调用的时候完全相同，canvasSize默认是{ width: 400, height: 400 }，这种方式不同的是不需要传参数target: this，同时新增percentage（进度条的百分比）：

Page({
  data: {
    config: {
      canvasSize: {
        width: 400,
        height: 400
      },
      percent: 100,
      barStyle: [{width: 20, fillStyle: '#f0f0f0'}, {width: 20, animate: true, fillStyle: [{position: 0, color: '#56B37F'}, {position: 1, color: '#c0e674'}]}],
      needDot: true,
      dotStyle: [{r: 20, fillStyle: '#ffffff', shadow: 'rgba(0,0,0,.15)'}, {r: 10, fillStyle: '#56B37F'}]
    },
    percentage: 0
  }
});

页面使用

<mpProgress config="{{config}}" percentage="{{percentage}}"></mpProgress>

该方式遵从双向绑定数据的原则，当页面改变percentage，mp-progress会自动更新视图

2、API的形式使用

import MpProgress from 'mp-progress';
// 初始化
// 注意：在wepy中必须在onReady里调用
const mprogress = new MpProgress({
  target: this,
  canvasId: 'progress',
  canvasSize: {width: 400, height: 400},
  barStyle: [{width: 12, fillStyle: '#f0f0f0'}, {width: 12, fillStyle: [{position: 0, color: '#56B37F'}, {position: 1, color: '#c0e674'}]}]
});

// 开始绘制进度，60代表60%
mprogress.draw(60);

使用

<canvas class="canvas" type="2d" id="progress"></canvas>

其他使用方式可以看github：https://github.com/lucaszhu2zgf/mp-progress