小程序实现跑马灯效果

<!-- 跑马灯效果 -->
<view class="example">
  <view class="marquee_box">
    <view class="marquee_text" 
          style="{{orientation}}:{{marqueeDistance}}px;font-size: {{size}}px;">
      <image src="{{adUrl}}" class='ad-image' />{{text}}
    </view>
  </view>
</view>

/* 跑马灯效果 */
.example {
  display: block;
  width: 100%;
  height: 70rpx;
  background-color: #f2f2f2;
  line-height: 70rpx;
}
.marquee_box {
  width: 100%;
  position: relative;
}
.marquee_text {
  white-space: nowrap;
  position: absolute;
  top: 0;
  display: flex;
  flex-direction: row;
}
.ad-image {
  width: 40rpx;
  height: 40rpx;
  margin-right: 10rpx;
  margin-top: 15rpx;
}

// pages/home/home.js
var app = getApp()
Page({
  data: {
    //跑马灯
    text: '618淘甄貨,一个可以省钱的购物平台',
    marqueePace: 1,//滚动速度
    marqueeDistance: 0,//初始滚动距离
    size: 14,
    orientation: 'left',//滚动方向
    intervals: 20, // 时间间隔
    adUrl: '../../images/detail/like.jpeg'
  },
  onShow: function () {
    // 页面显示
    var that = this;
    var length = that.data.text.length * that.data.size;//文字长度
    var windowWidth = wx.getSystemInfoSync().windowWidth;// 屏幕宽度
    that.setData({
      length: length,
      windowWidth: windowWidth,
    });
    that.runMarquee();// 水平一行字滚动完了再按照原来的方向滚动
  },
  runMarquee: function () {
    var that = this;
    var interval = setInterval(function () {
      //文字一直移动到末端
      if (-that.data.marqueeDistance < that.data.length) {
        that.setData({
          marqueeDistance: that.data.marqueeDistance - that.data.marqueePace,
        });
      } else {
        clearInterval(interval);
        that.setData({
          marqueeDistance: that.data.windowWidth
        });
        that.runMarquee();
      }
    }, that.data.intervals);
  }
})