vuejs2 - "Property or method is not defined on the instance but referenced during render"

Question

我需要在item.title之外显示<v-carousel>，但是出现以下错误消息:

[Vue warn]: Property or method "item" is not defined on the instance but referenced during render. Make sure that this property is reactive, either in the data option, or for class-based components, by initializing the property. See: https://vuejs.org/v2/guide/reactivity.html#Declaring-Reactive-Properties.

我检查了Stackoverflow搜索的结果，但我真的很难理解。如果有人可以通过这个例子向我解释一下，我将不胜感激。
这是我的代码:

<v-carousel>
<v-carousel-item v-for="(item,i) in items" v-bind:src="item.src" :key="i">
</v-carousel-item>
</v-carousel>

<h1>TITLE: {{ item.title }}</h1>

<script>
  export default {
    data () {
      return {
        items: [
          {
            src: '/static/a.jpg',
            title: 'A',
            text: 'texta'
          },
          {
            src: '/static/b.jpg',
            title: 'B',
            text: 'textb'
          }
          {
      }
    }
  }
</script>

这是我需要存档的内容:

一旦图像更改为下一个图像-范围外的 文本也应更改。我试图检查范围之外的item数组的值，但是它不起作用:<h1 v-if="(item,i) === 1">Lion</h1> <h1 v-if="(item,i) === 2">Ape</h1>如何访问范围之外的当前轮播项目的值？

Answer 1

您需要在v-model组件上添加v-carousel:

<v-carousel v-model="carousel">
    <v-carousel-item 
        v-for="(item,i) in items"
        v-bind:src="item.src"          
        :key="i"
    ></v-carousel-item>
</v-carousel>
//then set title like this:
<h1>TITLE: {{ items[carousel].title }}</h1>

并将 carousel变量添加到 data

data () {
  return {
    carousel: 0, //like this
    items: [
       ...