微信小程序-文字跑马灯效果

效果如图

WXML

<scroll-view class="container">
  <view class="scrolltxt">
    <view class="marquee_box">
      <view class="marquee_text" style="transform: translateX(-{{marqueeDistance}}px)">
        <text>{{text}}</text>
        <text style="margin-right:{{marquee_margin}}px;"></text>
        <text style="margin-right:{{marquee_margin}}px;">{{text}}</text>        
      </view>
    </view>
  </view>
</scroll-view>

WXSS

.container {display: flex;flex-direction: column;justify-content: space-between;box-sizing: border-box;}
.scrolltxt{padding:0 20rpx;background:#f8f8f8;}
.marquee_box {position:relative;color:#333;height:90rpx;display:block;overflow:hidden;} 
.marquee_text {white-space: nowrap;position:absolute;top:0;font-size:14px;height:90rpx;line-height:90rpx;}

JS

  data: {
    //滚动字幕
    text: "温馨提示：为了保证其他购买者的利益，每个 账号针对同一商品只允许退款一次，请您谨慎操作。",
    marqueePace: 1,//滚动速度
    marqueeDistance: 0,//初始滚动距离
    marquee_margin: 30,//间距
    size: 14,//字号
   time: '',// 定时器
  },

onHide: function () {
    //清空滚动字幕定时器，避免锁屏或页面隐藏后移动速度越来越快
    clearInterval(this.data.time);
  },

  onShow: function (e) {
    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
    //console.log(length,windowWidth);
    that.setData({
      length: length,
      windowWidth: windowWidth
    });
    that.scrolltxt();// 第一个字消失后立即从右边出现
  },

 /**
   * 滚动字幕
   */
  scrolltxt: function () {
    var that = this;
    var length = that.data.length;//滚动文字的宽度
    var windowWidth = that.data.windowWidth;//屏幕宽度
    var time = this.data.time
    if (length > windowWidth) {
      time = setInterval(function () {
        var maxscrollwidth = length + that.data.marquee_margin;//滚动的最大宽度，文字宽度+间距，如果需要一行文字滚完后再显示第二行可以修改marquee_margin值等于windowWidth即可
        var crentleft = that.data.marqueeDistance;
        if (crentleft < maxscrollwidth) {//判断是否滚动到最大宽度
          that.setData({
            marqueeDistance: crentleft + that.data.marqueePace
          })
        }
        else {
          that.setData({
            marqueeDistance: 0 // 直接重新滚动
          });
          clearInterval(time);
          that.scrolltxt();
        }
      }, 20);
    }
    else {
      that.setData({ marquee_margin: "1000" });//只显示一条不滚动右边间距加大，防止重复显示
    }
    that.setData({
      time:time
    })
  },