WeChat Mini Program - Realize a progress bar with a slider

  In response to the needs of the WeChat applet project, it is necessary to implement a progress bar with a slider that can slide left and right. After reading the documentation of the applet, I found that the progress component above cannot meet the requirements, so I wrote one myself, and summarize it here.

1. Rendering

2. Realize the logic

The logic of function realization is relatively simple, here is a brief explanation:

1. First, wrap the relevant code with a label and add static positioning;
2. Draw two identical lines, one of them adds relative positioning to change the color of the line, and dynamically sets its width;
3. Draw a slider, use relative positioning to fix it on the line, add a bindtouchmove event to it, get its width from the left, and then set it accordingly.

3. Related codes

1. wxml file

<view class="process_wrap">
  <view class="line" bindtap="moveTo"></view>
  <!-- 这里的宽度和left值也可以改成百分比，效果是一样的 -->
  <view class="active_line" style="width:{ 
        { 
        2*progress}}rpx;" bindtap="moveTo"></view>
  <view class="spot" style="left:{ 
        { 
        2*progress}}rpx" bindtouchmove="moveTo"  catchtouchstart="buttonStart"></view>
  <view style="margin-top:50rpx;">{
   
   {precent}}%</view>
</view>

2. js file

var startPoint;
const min = 0; // 最小宽度 单位px
const max = 200; // 最大宽度  单位px

Page({
    
    
  /**
   * 页面的初始数据
   */
  data: {
    
    
    buttonLeft: 0,
    progress: 0, // 进度条的宽度，这里的单位是px，所以在wxml文件中要改为rpx
    precent:0 // 这个是百分比
  },
  buttonStart: function (e) {
    
    
    startPoint = e.touches[0]
  },
  moveTo(e) {
    
    
    var endPoint = e.touches[e.touches.length - 1]
    var translateX = endPoint.clientX - startPoint.clientX
    startPoint = endPoint;
    var buttonLeft = this.data.buttonLeft + translateX;
    if (buttonLeft > max) {
    
    
      // 滑动位置大于进度条最大宽度的时候让它为最大宽度
      buttonLeft = max
    }
    if (buttonLeft < min) {
    
    
      // 滑动位置小于进度条最大宽度的时候让它为最小宽度
      buttonLeft = min
    }
    this.setData({
    
    
      buttonLeft: buttonLeft,
      progress: buttonLeft,
      precent:parseInt((buttonLeft/max)*100)
    })
  }
})

3. wxss file

.process_wrap {
    
    
  position: relative;
  width: 400rpx;
  margin-left: 60rpx;
}
.process_wrap .line {
    
    
  width: 400rpx;
  height: 2rpx;
  background: #B5B8C2;
}

.process_wrap .active_line {
    
    
  position: absolute;
  top: -4rpx;
  left: 0;
  max-width: 400rpx;
  height: 8rpx;
  background: linear-gradient(83deg, #84B3FF 0%, #116DF6 100%);
}

.process_wrap .spot {
    
    
  position: absolute;
  top: -20rpx;
  left: 0;
  width: 40rpx;
  height: 40rpx;
  background: #1A73FF;
  box-shadow: 0px 2px 10px 0px rgba(196, 200, 204, 0.5);
  border: 2px solid #FFFFFF;
  border-radius: 100%;
}