WeChat applet realizes barrage effect-Mini Program Development-php.cn

There are many demos online now, but it is not easy to find the one you need. Today I would like to share with you a barrage function I wrote.

Let’s take a look at the rendering:

WeChat applet realizes barrage effect

##The wxml code is as follows:

<!-- 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>

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wxss code is as follows:

/* 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;
}

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##In this way, all the basic styles are implemented. Next, we need to process the words on the barrage.

The text moves from right to left. The top position of the text is random, and the left position is the width of the screen. When moving, timer is used for processing.

Also, the color of the font appears randomly. These functions are all handled using js.

js code is as follows:

var barrage_style_arr = [];
var barrage_style_obj ={};
var phoneWidth = 0;
var timers = [];
var timer ;
Page({
  data: {
    imgUrls: [
      &#39;http://img02.tooopen.com/images/20150928/tooopen_sy_143912755726.jpg&#39;,
      &#39;http://img06.tooopen.com/images/20160818/tooopen_sy_175866434296.jpg&#39;,
      &#39;http://img06.tooopen.com/images/20160818/tooopen_sy_175833047715.jpg&#39;
    ],
    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
    })
  },
})

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##Because I have just come into contact with small programs, I don’t know much about the use of some statements. So I encountered some problems:

#1. Obtain wxml control information in js.

js：

barrageSwitch: function(e){
    console.log(e);
  }

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#wxml：

# Result: An objec is returned. The types returned in the console seem to be data in json format.

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

2. When implementing the barrage, click the launch button to get the information of the input box.

Here, when the input box loses focus, I copy the data to the data class in js, and then take the value in the data class when I click to launch.

#3. The biggest problem is how to make the text run, because the mini program does not support jQuery, which makes me, a js idiot, a little helpless.

Let me talk about my idea of moving text:

First, define a timer when opening the barrage and close it. Turn off the timer when posting. Because I use an array to store the text movement style, the rest is determined. I just need to change the size of the left to make the text move. So I use a for loop to change the size of the barrage text style left: xxx px; when the timer is running.

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