wepy写小程序之文字水平滚动

近期有一个显示文字水平滚动的需求，思考了半天写了几行小程序代码，一言不合就上代码：

wxml

<view class="rollCon">

    <view class="box">

        <view class="text"  style="left:{{offsetLeft}}px"> {{text}} </view>

    </view>

</view>

wxss

.rollCon{position: fixed;bottom: 0;left: 0;width: 100%;height: 60rpx;z-index: 100;background: #FDE8C7;font-size: 20rpx;line-height: 60rpx;}

.box {width: 100%;position: relative;}

.text {white-space: nowrap;position: absolute;top: 0;}//注意一定要用nowrap。。。

js

data={text:'共0张 价税合计：12121 金额：2323233 税额：232423',

pace: 1,//滚动速度

start: 0,//初始滚动距离

interval:20,//时间间隔

size:14,

length:0,

windowWidth:0,}

//文字走马灯

run(){

let that = this;

let interval = setInterval(function () {if (-that.start < that.length) {

that.start = that.start - that.pace;

that.$apply();

} else {

clearInterval(interval);

that.start = that.windowWidth;

that.run();

that.$apply();}

}, that.interval);}

onshow(){

//文字滚动

let length = (this.text.length-20) * this.size;//文字长度

let windowWidth = wx.getSystemInfoSync().windowWidth;// 屏幕宽度

this.length = length;this.windowWidth = windowWidth;

this.$apply()

this.run();}

定时器每次触发时，调用this.$apply()来更新data数据 ，要不每次只执行一次，数据 得不到改变！！！