title: Get Checkbox index in a ListView in nativescript-vue
body: <p>I have a checkbox inside a <code>ListView</code> component that has a <code>for loop</code></p>
  
  <p>I need to get the index number of the checked item so I can remove/modify it in the array but I'm unable to do that as there's no <code>:key</code> prop like in Vue.</p>
  
  <p>This is how I'm rendering the list. I'm still new to mobile apps development so I'm not sure whether to use a <code>Label</code> with the checkboxes or just use the <code>text</code> attribute to add the text. WHat is the normal convention here?</p>
  
  <p>I can get the index number of the item with <code>@itemTap</code> on <code>ListView</code> . However, it stops working when I add <code>@checkedChange</code> to the <code>CheckBox</code> tag.</p>
  
  <p>Also something minor I found, I am unable to tap the checkbox to change its state (click in my case since im using an emulator). I have to tap on the text associated with it <code>:text="task.title"</code> and if I remove the text, I have no way to toggle its state.</p>
  
  <pre><code>&lt;ListView for="(task, index) in tasks" @itemTap="onLabelTap"&gt;
      &lt;v-template&gt;
          &lt;GridLayout columns="auto,*"&gt;
              &lt;!-- Shows the list item label in the default color and style. --&gt;
              &lt;CheckBox :text="task.title" :checked="task.isChecked" @checkedChange="onCheckChange" col="0" /&gt;
              &lt;!--&lt;Label :text="task.text" class="item" col="1" /&gt;--&gt;
          &lt;/GridLayout&gt;
      &lt;/v-template&gt;
  &lt;/ListView&gt;
  </code></pre>
  
  <p>The javascript</p>
  
  <pre><code>data() {
      return {
          tasks: [
              {'id': 0, 'title': 'One', isChecked: false},
              {'id': 1, 'title': 'Two', isChecked: true},
              {'id': 2, 'title': 'Three', isChecked: false}
          ],
      }
  },
  computed: {
      message() {
          return "&lt;!-- Tasks Page --&gt;";
      }
  },
  methods: {
      onDrawerButtonTap() {
          utils.showDrawer();
      },
      onLabelTap(event) {
          alert('You clicked on ' + event.index) // I can access `event.index` here
              .then(() =&gt; {
                  console.log("Alert dialog closed.");
              });
      },
      onCheckChange(event) {
          this.isChecked = event.value;
          console.log(this.isChecked);
          console.log(event.index); // but I can't access it here
      }
  </code></pre>