微信小程序滚动字幕及弹幕的实现技巧

<!-- pages/index/index.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/index/index.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;

}

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

   })

 },

})

barrageSwitch: function(e){

   console.log(e);

 }

<switch id="switch_" bindchange="barrageSwitch"/>

Object {type: "change", timeStamp: 2766, target: Object, currentTarget: Object, detail: Object}