小程序实现左右来回滚动字幕效果

<!--pages/market/market.wxml-->
<swiper indicator-dots="{{indicatorDots}}"
 autoplay="{{autoplay}}" interval="{{interval}}" duration="{{duration}}">
 <block wx:for="{{imgUrls}}" wx:key="unique">
 <swiper-item>
  <image src="{{item}}" class="slide-image"/>
 </swiper-item>
 </block>
</swiper>
 
<!--弹幕开关-->
<view class="barrage-Switch" style="color:{{barrageTextColor}};">
 <switch id="switch_" bindchange="barrageSwitch"/>
 <text>弹幕</text>
</view>
 
<!--弹幕输入框-->
 <view class="barrage-inputText" style="display:{{barrage_inputText}}">
  <view class="barrage-input">
  <input bindblur="bind_shoot" value="{{bind_shootValue}}"/>
  </view>
  <view class="barrage-shoot">
   <button class="shoot" size="mini" bindtap="shoot">发射</button>
  </view>
 </view>
 
<!--弹幕上单文字-->
<view class="barrage-fly" style="display:{{barragefly_display}}">
 <block wx:for="{{barrage_style}}" wx:key="unique">
 <text class="barrage-textFly" style="color:{{item.barrage_shoottextColor}};left:{{item.barrage_phoneWidth}}px;top:{{item.barrageText_height}}px;">{{item.barrage_shootText}}</text>
 </block>
</view>

/* pages/market/market.wxss */
.slide-image{
 width: 100%;
}
 
/* 弹幕选择按钮的操作*/
.barrage-Switch{
 position: absolute;
 bottom: 10px;
 right: 10px;
 z-index: 2;
}
 
/* 弹幕输入框的操作*/
.barrage-inputText{
 position: absolute;
 display: flex;
 background-color: #BFBFBF;
 width: 100%;
 height: 40px;
 flex-direction: row;
 nav-index: 2;
 justify-content: center;
 align-items: center;
 bottom: 10%;
}
.barrage-input{
 background-color: greenyellow;
 width: 60%;
 height: 30px;
}
.barrage-shoot{
 
 margin-left: 10px;
 width: 25%;
 height: 30px;
}
.shoot{
 width: 100%;
 color: black;
}
 
/*弹幕飞飞飞*/
.barrage-fly{
 z-index: 3;
 height: 80%;
 width: 100%;
 position: absolute;
 top: 0;
}
.barrage-textFly{
 position: absolute;
 
}

// pages/market/market.js
var barrage_style_arr = [];
var barrage_style_obj = {};
var phoneWidth = 0;
var timers = [];
var timer;
Page({
 data: {
 imgUrls: [
  'http://img02.tooopen.com/images/20150928/tooopen_sy_143912755726.jpg',
  'http://img06.tooopen.com/images/20160818/tooopen_sy_175866434296.jpg',
  'http://img06.tooopen.com/images/20160818/tooopen_sy_175833047715.jpg'
 ],
 indicatorDots: true,
 autoplay: true,
 interval: 3000,
 duration: 500,
 barrageTextColor: "#D3D3D3",
 barrage_inputText: "none",
 barrage_shoottextColor: "black",
 bind_shootValue: "",
 barrage_style: [],
 barragefly_display: "none",
 },
 
 
 // 生命周期函数--监听页面加载
 onLoad: function (options) {
 var that = this;
 //获取屏幕的宽度
 wx.getSystemInfo({
  success: function (res) {
  that.setData({
   barrage_phoneWidth: res.windowWidth - 100,
  })
  }
 })
 phoneWidth = that.data.barrage_phoneWidth;
 console.log(phoneWidth);
 },
 
 //是否打开弹幕...
 barrageSwitch: function (e) {
 console.log(e);
 //先判断没有打开
 if (!e.detail.value) {
  //清空弹幕
  barrage_style_arr = [];
  //设置data的值
  this.setData({
  barrageTextColor: "#D3D3D3",
  barrage_inputText: "none",
  barragefly_display: "none",
  barrage_style: barrage_style_arr,
  });
  //清除定时器
  clearInterval(timer);
 } else {
  this.setData({
  barrageTextColor: "#04BE02",
  barrage_inputText: "flex",
  barragefly_display: "block",
  });
  //打开定时器
  timer = setInterval(this.barrageText_move, 800)
 }
 },
 
 //发射按钮
 shoot: function (e) {
 
 //字体颜色随机
 var textColor = "rgb(" + parseInt(Math.random() * 256) + "," + parseInt(Math.random() * 256) + "," + parseInt(Math.random() * 256) + ")";
 // //设置弹幕字体的水平位置样式
 // var textWidth = -(this.data.bind_shootValue.length*0);
 //设置弹幕字体的垂直位置样式
 var barrageText_height = (Math.random()) * 266;
 barrage_style_obj = {
  // textWidth:textWidth,
  barrageText_height: barrageText_height,
  barrage_shootText: this.data.bind_shootValue,
  barrage_shoottextColor: textColor,
  barrage_phoneWidth: phoneWidth
 };
 barrage_style_arr.push(barrage_style_obj);
 this.setData({
  barrage_style: barrage_style_arr,  //发送弹幕
  bind_shootValue: ""     //清空输入框
 })
 
 //定时器 让弹幕动起来
 // this.timer= setInterval(this.barrageText_move,800);
 
 },
 
 //定时器 让弹幕动起来
 barrageText_move: function () {
 var timerNum = barrage_style_arr.length;
 var textMove;
 for (var i = 0; i < timerNum; i++) {
  textMove = barrage_style_arr[i].barrage_phoneWidth;
  console.log("barrage_style_arr[" + i + "].barrage_phoneWidth----------:" + barrage_style_arr[i].barrage_phoneWidth);
  textMove = textMove - 20;
  barrage_style_arr[i].barrage_phoneWidth = textMove;
  //走完的移除掉
  if (textMove <= -100) {
  //   clearTimeout(this.timer);
  barrage_style_arr.splice(0, 1);
  i--;
  //全部弹幕运行完
  if (barrage_style_arr.length == 0) {
   this.setData({
   barrage_style: barrage_style_arr,
   })
   // clearInterval(this.timer);
   return;
  }
  }
  console.log("第" + i + "个定时器:", textMove);
  this.setData({
  barrage_style: barrage_style_arr,
  })
 }
 
 
 },
 
 //绑定发射输入框，将值传递给data里的bind_shootValue，发射的时候调用
 bind_shoot: function (e) {
 this.setData({
  bind_shootValue: e.detail.value
 })
 },
 
})