微信小程序實現滾動條功能

<view class="conty">
  <!-- 滾動字幕 -->
<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>
</view>

data: {
  text: "這是一條農協動態，請您仔細閱讀，若內容有所問題，請聯系客服！",
  marqueePace: 1,//滾動速度
  marqueeDistance: 0,//初始滾動距離
  marquee_margin: 30,
  size:14,
  interval: 20 ,// 時間間隔
  HomeIndex:0,
  },
 onShow: function () {
  var that = this;
  var length = that.data.text.length * that.data.size;//文字長度
  var windowWidth = wx.getSystemInfoSync().windowWidth;// 屏幕寬度
  //console.log(length,windowWidth);
  that.setData({
   length: length,
   windowWidth: windowWidth
  });
  that.scrolltxt();// 第一個字消失後立即從右邊出現
  },
   
  scrolltxt: function () {
  var that = this;
  var length = that.data.length;//滾動文字的寬度
  var windowWidth = that.data.windowWidth;//屏幕寬度
  if (length > windowWidth){
   var interval = setInterval(function () {
   var maxscrollwidth = length + that.data.marquee_margin;//滾動的最大寬度，文字寬度+間距，如果需要一行文字滾完後再顯示第二行可以修改marquee_margin值等於windowWidth即可
   var crentleft = that.data.marqueeDistance;
   if (crentleft < maxscrollwidth) {//判斷是否滾動到最大寬度
    that.setData({
    marqueeDistance: crentleft + that.data.marqueePace
    })
   }
   else {
    //console.log("替換");
    that.setData({
    marqueeDistance: 0 // 直接重新滾動
    });
    clearInterval(interval);
    that.scrolltxt();
   }
   }, that.data.interval);
  }
  else{
   that.setData({ marquee_margin:"1000"});//隻顯示一條不滾動右邊間距加大，防止重復顯示
  } 
  }

.scrolltxt{
  width: 100%;
  padding:0 20rpx;
  background:#2a4d69;
}
.marquee_box {
  position:relative;
  color:white;
  height:90rpx;display:
  block;overflow:hidden;
} 
.marquee_text {
  white-space: nowrap;
  position:absolute;
  top:0;
  font-size:14px;
  height:90rpx;
  line-height:90rpx;
}