[JavaScript知识库] 圆环进度条两种实现方式

开发: C++知识库 Java知识库 JavaScript Python PHP知识库人工智能区块链大数据移动开发嵌入式开发工具数据结构与算法开发测试游戏开发网络协议系统运维
教程: HTML教程 CSS教程 JavaScript教程 Go语言教程 JQuery教程 VUE教程 VUE3教程 Bootstrap教程 SQL数据库教程 C语言教程 C++教程 Java教程 Python教程 Python3教程 C#教程
数码: 电脑笔记本显卡显示器固态硬盘硬盘耳机手机 iphone vivo oppo 小米华为单反装机图拉丁

-> JavaScript知识库 -> 圆环进度条两种实现方式 -> 正文阅读

[JavaScript知识库]圆环进度条两种实现方式

先看图效果图：

这边UI的设计图长这样

?

?一个圆环的进度展示，这个圆环上开始位置是齐口的，终点圆口，并且有一个圆；

列举了两种实现方式：

第一种纯的CSS实现；原理是叠加和旋转而成。缺点在某些机型上面应为遮罩没有对齐（uniapp 半个像素不显示的问题，其他平台没有这问题），会出现白边（没有遮挡好的情况）
?第二种 createCanvasContext 直接画弧线；动态计算原点位置叠加显示

第一种实现方式?

理论上：纯css? 两个半圆在相应的取值范围内旋转，旋转的时候被父对象遮罩剩余的部分

第一步： 两个半圆在旋转，旋转时候被父对象 clip 掉剩余部分，两个红色底就是两个半圆的父元素，红色第里面的两个深色块就是将要旋转的元素；

<view class="box0-parent">
  <view class="box0" :style="box0Style">
  </view>
</view>
<view class="box1-parent">
  <view class="box1" :style="box1Style">
  </view>
</view>


.box0-parent {
  position: absolute;
  top: 580rpx;
  width: 284rpx;
  height: 284rpx;
  background-color: #dd2124;
  clip: rect(0px, 142rpx, 284rpx, 0px);

  // border-radius: 50%;
  .box0 {
    position: absolute;
    top: 0;
    width: 284rpx;
    height: 284rpx;
    background-color: #2C405A;
    clip: rect(0px, 142rpx, 284rpx, 0px);
    border-radius: 50%;
  }
}

.box1-parent {
  position: absolute;
  top: 580rpx;
  width: 284rpx;
  height: 284rpx;
  background-color: #c34c24;
  clip: rect(0px, 284rpx, 284rpx, 142rpx);
  // border-radius: 50%;

  .box1 {
    position: absolute;
    top: 0;
    width: 284rpx;
    height: 284rpx;
    background-color: #5a4600;
    clip: rect(0px, 284rpx, 284rpx, 142rpx);
    border-radius: 50%;
    // transform: rotate(60deg);
  }
}

?第二步： 调整下参数；再调下颜色

<template>
  <view class="process">

    <view class="box0-parent">
      <view class="box0" :style="box0Style">
      </view>
    </view>
    <view class="box1-parent">
      <view class="box1" :style="box1Style">
      </view>
    </view>

    <view class="input-range">
      <text> {{percent}}%</text> <text style="margin-left: 100rpx;">{{percent*3.6}}</text>
      <slider @changing="onChange" value="0" max="100" min="0" v-model="percent" activeColor="#FFCC33"
        backgroundColor="#000000" block-color="#8A6DE9"></slider>
    </view>


  </view>

</template>

<script>
 
  export default {
    data() {
      return {
        percent: 30,
      }
    },
    computed: {
      box0Style() {
        if (this.percent >= 50) {
          return `transform: rotate(${180 + this.percent*3.6}deg)`
        } else {
          return ``
        }
      },
      box1Style() {
        if (this.percent <= 50) {
          return `transform: rotate(${this.percent*3.6}deg)`
        } else {
          return `display: none;`
        }
      }
    },
    methods: {
      onChange(value) {
        // console.log(value.detail.value)
        this.percent = value.detail.value
      }
    }
  }
</script>

<style lang="scss" scoped>
  .process {
    width: 100%;

    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;


    .input-range {
      position: absolute;
      top: 980rpx;
      width: 300rpx;
    }

    .box0-parent {
      position: absolute;
      top: 580rpx;
      width: 284rpx;
      height: 284rpx;
      background-color: #dd2124;
      clip: rect(0px, 142rpx, 284rpx, 0px);

      // border-radius: 50%;
      .box0 {
        position: absolute;
        top: 0;
        width: 284rpx;
        height: 284rpx;
        //background-color: #2C405A;
        background-color: #2168F9;
        clip: rect(0px, 142rpx, 284rpx, 0px);
        border-radius: 50%;
      }
    }

    .box1-parent {
      position: absolute;
      top: 580rpx;
      width: 284rpx;
      height: 284rpx;
      //background-color: #c34c24;
      background-color: #dd2124;
      // background-color: #2168F9;
      clip: rect(0px, 284rpx, 284rpx, 142rpx);
      // border-radius: 50%;

      .box1 {
        position: absolute;
        top: 0;
        width: 284rpx;
        height: 284rpx;
        // background-color: #5a4600;
        background-color: #2168F9;
        clip: rect(0px, 284rpx, 284rpx, 142rpx);
        border-radius: 50%;
        // transform: rotate(60deg);
      }
    }

  }
</style>

然后加上蓝色底色，圆环换上白色；真理下就能得到这么的圆环了；

至于白色圆点? 直接绝对定位于半圆，随着半圆移动即可；每个半圆都有一个

第二种实现方式

使用的是 canvas 中的?arc? （画弧线来实现的）

uni.createCanvasContexthttps://uniapp.dcloud.io/api/canvas/CanvasContext.html


<canvas class="canvas-content" :canvas-id="canvasId" :id="canvasId">
</canvas>

methods: {
  onChange(value) {
    // console.log(value.detail.value)
    this.percent = value.detail.value
    this.drawCircleByProgress()
  },
  drawCircleByProgress(){
    // 表示进度的两端为圆形  目前没有找到只设置一段的方式
    this.canvasContent.setLineCap('round'); //圆形     
    this.canvasContent.setLineCap('square'); //方形
    // 设置线条的宽度和颜色
    this.canvasContent.setLineWidth(uni.upx2px(30));
    this.canvasContent.setStrokeStyle('#ff0000');
          
    let endAngle = ((2 * Math.PI) / 100) * this.percent + this.startAngle;
    
    this.canvasContent.beginPath();
    // 半径为整个canvas宽度的一半
    let radius = uni.upx2px(284) / 2;
    this.canvasContent.arc(radius, radius, radius - uni.upx2px(30), this.startAngle, endAngle, false);
    this.canvasContent.stroke();
    
    this.canvasContent.draw();
  }
}

.canvas-content{
  width: 284rpx;
  height: 284rpx;
  background-color: #059cdd;
}

这种方式对于圆环中的画一个白色球； 需要通过弧度计算圆上一点的位置；

drawCircleByProgress() {
  // 表示进度的两端为圆形  目前没有找到只设置一段的方式
  this.canvasContent.setLineCap('round'); //圆形     
  this.canvasContent.setLineCap('square'); //方形

  let width = uni.upx2px(30)

  // 设置线条的宽度和颜色
  this.canvasContent.setLineWidth(width);
  this.canvasContent.setStrokeStyle('#ff0000');


  // 画圆环
  let endAngle = ((2 * Math.PI) / 100) * this.percent + this.startAngle;
  this.canvasContent.beginPath();
  // 半径为整个canvas宽度的一半
  let radius = uni.upx2px(284) / 2;
  this.canvasContent.arc(radius, radius, radius - width, this.startAngle, endAngle, false);
  this.canvasContent.stroke();



  //原点要在 圆弧前面一点点的位置 所有这个加了 0.1；
  let p0x = radius + Math.cos(endAngle + .1) * (radius - width)
  let p0y = radius + Math.sin(endAngle + .1) * (radius - width)
  // 画圆球
  this.canvasContent.beginPath()
  this.canvasContent.arc(p0x, p0y, width / 2, 0, 2 * Math.PI)
  this.canvasContent.setFillStyle('#F0AD4E');
  this.canvasContent.fill()
  // 画白色圆球
  this.canvasContent.beginPath()
  this.canvasContent.arc(p0x, p0y, width * 0.4, 0, 2 * Math.PI)
  this.canvasContent.setFillStyle('#FFFFFF');
  this.canvasContent.fill()

  this.canvasContent.draw();
}

真理下就能得到下面的例子了

完整代码：

<template>
  <view class="process">

    <canvas class="canvas-content" :canvas-id="canvasId" :id="canvasId">
    </canvas>

    <view class="box0-parent">
      <view class="box0" :style="box0Style">
      </view>
    </view>
    <view class="box1-parent">
      <view class="box1" :style="box1Style">
      </view>
    </view>
    <view class="input-range">
      <text> {{percent}}%</text> <text style="margin-left: 100rpx;">{{percent*3.6}}</text>
      <slider @changing="onChange" value="0" max="100" min="0" v-model="percent" activeColor="#FFCC33"
        backgroundColor="#000000" block-color="#8A6DE9"></slider>
    </view>

  </view>
</template>

<script>
  export default {
    data() {
      return {
        percent: 30,
        canvasId: 'canvasId',
        canvasContent: null,
        startAngle: -Math.PI / 2, //canvas画圆的起始角度，默认为3点钟方向即90度 方向，定位位到12位置 0度
      }
    },
    computed: {
      box0Style() {
        if (this.percent >= 50) {
          return `transform: rotate(${180 + this.percent*3.6}deg)`
        } else {
          return ``
        }
      },
      box1Style() {
        if (this.percent <= 50) {
          return `transform: rotate(${this.percent*3.6}deg)`
        } else {
          return `display: none;`
        }
      }
    },
    onShow() {
      this.canvasContent = uni.createCanvasContext(this.canvasId, this)
      this.drawCircleByProgress()
    },
    methods: {
      onChange(value) {
        // console.log(value.detail.value)
        this.percent = value.detail.value
        this.drawCircleByProgress()
      },
      drawCircleByProgress() {
        // 表示进度的两端为圆形  目前没有找到只设置一段的方式
        this.canvasContent.setLineCap('round'); //圆形     
        this.canvasContent.setLineCap('square'); //方形

        let width = uni.upx2px(30)

        // 设置线条的宽度和颜色
        this.canvasContent.setLineWidth(width);
        this.canvasContent.setStrokeStyle('#ff0000');

        let endAngle = ((2 * Math.PI) / 100) * this.percent + this.startAngle;

        this.canvasContent.beginPath();
        // 半径为整个canvas宽度的一半
        let radius = uni.upx2px(284) / 2;
        this.canvasContent.arc(radius, radius, radius - width, this.startAngle, endAngle, false);
        this.canvasContent.stroke();

        //原点要在 圆弧前面一点点的位置 所有这个加了 0.1；
        let p0x = radius + Math.cos(endAngle + .1) * (radius - width)
        let p0y = radius + Math.sin(endAngle + .1) * (radius - width)


        this.canvasContent.beginPath()
        this.canvasContent.arc(p0x, p0y, width / 2, 0, 2 * Math.PI)
        this.canvasContent.setFillStyle('#F0AD4E');
        this.canvasContent.fill()

        this.canvasContent.beginPath()
        this.canvasContent.arc(p0x, p0y, width * 0.4, 0, 2 * Math.PI)
        this.canvasContent.setFillStyle('#FFFFFF');
        this.canvasContent.fill()

        this.canvasContent.draw();
      }
    }
  }
</script>

<style lang="scss" scoped>
  .process {
    width: 100%;

    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;

    .canvas-content {
      width: 284rpx;
      height: 284rpx;
      background-color: #059cdd;
    }

    .input-range {
      position: absolute;
      top: 750rpx;
      width: 300rpx;
    }

    .box0-parent {
      position: absolute;
      top: 380rpx;
      width: 284rpx;
      height: 284rpx;
      background-color: #dd2124;
      clip: rect(0px, 142rpx, 284rpx, 0px);

      // border-radius: 50%;
      .box0 {
        position: absolute;
        top: 0;
        width: 284rpx;
        height: 284rpx;
        //background-color: #2C405A;
        background-color: #2168F9;
        clip: rect(0px, 142rpx, 284rpx, 0px);
        border-radius: 50%;
      }
    }

    .box1-parent {
      position: absolute;
      top: 380rpx;
      width: 284rpx;
      height: 284rpx;
      //background-color: #c34c24;
      background-color: #dd2124;
      // background-color: #2168F9;
      clip: rect(0px, 284rpx, 284rpx, 142rpx);

      // border-radius: 50%;
      .box1 {
        position: absolute;
        top: 0;
        width: 284rpx;
        height: 284rpx;
        // background-color: #5a4600;
        background-color: #2168F9;
        clip: rect(0px, 284rpx, 284rpx, 142rpx);
        border-radius: 50%;
        // transform: rotate(60deg);
      }
    }

  }
</style>