SOURCE

window.onload = function() {
    new Vue({
        el: '#app',
        data: {
            list: []
        },
        methods: {
            fetchData() {
                this.list = [{count:0}, {count:1}]
            }
        }
    })
}

<div id="app">
    <button @click="fetchData">模拟请求后端数据</button>
    <ul>
        <li v-for="(item, index) in list">
            <button @click="item.count--">-</button>
            <input v-model="item.count" />
            <button @click="item.count++">+</button>
        </li>
    </ul>
</div>