小程序 点击item 自动居中 scroll-view scrollLeft

HTML的代码

    
        
            {{item.title}}
        
    

逻辑的

    data = {
        topArray: [
            { title: '游览点哈', id: 2},
            { title: '卫生间哈', id: 13 },
            { title: '视频监控', id: 11 },
            { title: '智能广播', id: 12 },
            { title: '出入口哈', id: 14 },
            { title: '观光车哈', id: 15 },
            { title: '智能广播', id: 16 },
            { title: '出入口哈', id: 17 },
            { title: '观光哈哈', id: 18 },
            { title: '智能广播', id: 19 },
            { title: '出入口哈', id: 20 },
            { title: '观光车哈', id: 21 },
            { title: '出入口哈', id: 22 },
            { title: '观光车哈', id: 23 },
            { title: '智能广播', id: 24 },
            { title: '出入口哈', id: 25 },
            { title: '观光哈哈', id: 26 },
            { title: '智能广播', id: 27 },
            { title: '出入口哈', id: 28 },
            { title: '观光车哈', id: 29 },
        ],
        scrollViewWidth:'',
        scrollLeft:'',
    };
    methods = {
        switchClass(e){
            let offsetLeft = e.currentTarget.offsetLeft
            let idkl = e.currentTarget.dataset.id
            this.scrollLeft = offsetLeft - this.scrollViewWidth / 2  + 40
            console.log("this.scrollLeft>>>>" + JSON.stringify(this.scrollLeft))
            this.topArray.map(item=>{
                if(idkl == item.id){
                    item.select = true
                }else{
                    item.select = false
                }
                return item
            })
            this.$apply();
        }
    };
    onReady(){
        wx.createSelectorQuery().select('.scroll-view').boundingClientRect((rect)=>{
            this.scrollViewWidth = Math.round(rect.width)
            console.log("scrollViewWidth>>>>" + JSON.stringify(this.scrollViewWidth))
        }).exec() 
    }
    onLoad (options) {
        let self = this;
        self.topArray.map(item=>{
            item.select = false
            return item
        })
        self.topArray[0].select = true;
        self.$apply();
    }

CSS的代码

.scroll-view{
    display: inline-block;
    height: 80rpx;
    white-space: nowrap;
}
.class-item{
    display: inline-block;
    width:150rpx;
    text-align: center;
    font-size: 26rpx;
    color: #333;
    height: 80rpx;
    line-height: 80rpx;
    position: relative;
}
.fujia{
    color: red;
    font-size: 30rpx;
    font-weight: bold;
}
.fujia::after{
    content: '';
    position: absolute;
    left: 55rpx;
    bottom: 0;
    right: 0;
    width: 40rpx;
    height: 4rpx;
    background-color: red;
}