dart - 如何获取列表 Flutter 中选中项的索引/键？

Question

I'm using ListTile to create each item in the list. Each item is created dynamically from the data array. ListTile 提供了onTap，但对我来说还不够，因为我需要通过获取key 或index 来找出点击了哪个item。

ListTile:

     new ListTile(
        //leading: const Icon(Icons.flight_land),
        title: const Text('Trix\'s airplane'),
        subtitle:  const Text('The airplane is only in Act II.'),
        enabled: true,
        onTap: () { //TODO: get the identifier for this item },
        trailing: new Container(
          child: new Row(
            children: [
              new Text("70%"),
              const Icon(Icons.flight_land)
]
)
        ),
    )

Answer 1

您可能希望在 ListView 中构建您的 ListTile 列表，并使用 List.generate 构造函数来获取children 这里是一个简单的例子:

import "package:flutter/material.dart";

class ListTest extends StatefulWidget {
  @override
  _ListTestState createState() => new _ListTestState();
}

class _ListTestState extends State<ListTest> {
  final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();
  int _id;
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      key: _scaffoldKey,
      appBar: new AppBar(title: new Text("List"),),
      body: new ListView(
          children: new List.generate(10, (int index){
            return new ListTile(title: new Text("item#$index"),
            onTap:(){
              setState((){
                _id = index; //if you want to assign the index somewhere to check
              });
              _scaffoldKey.currentState.showSnackBar(new SnackBar(content: new Text("You clicked item number $_id")));
            },
            );
          })

      ),
    );
  }
}

请记住，List.generate 适用于小型列表，如果您正在阅读可扩展列表(例如:用户列表)，则需要使用 ListView.builder 而不是 ListView 它有一个 builder 参数，允许您按索引循环遍历列表。

new ListView.builder(itemBuilder: (BuildContext context, int index) {
        //return your list
      },