Question

嗨，我有一个文本表单字段，当表单被填充时，我想使用listview.builder在多个页面上输出值。当前，我可以在单个容器中输出数据，当我再次填充表单时，可以不添加其他容器，它只是更新当前容器的值如果有人知道该怎么做，请帮忙

Answer 1

完整的示例：

来源：

import 'package:flutter/material.dart';

class Demo extends StatefulWidget {
  @override
  _DemoState createState() => new _DemoState();
}

class _DemoState extends State<Demo> {
  List<String> _items = new List(); // to store comments

  final myController = TextEditingController();

  void _addComment() {
    if (myController.text.isNotEmpty) {
      // check if the comments text input is not empty
      setState(() {
        _items.add(myController.text); // add new commnet to the existing list
      });

      myController.clear(); // clear the text from the input
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(title: Text("DEMO")),
        body: Container(
            padding: EdgeInsets.all(15),
            child: Column(children: [
              Row(
                  crossAxisAlignment: CrossAxisAlignment.center,
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: <Widget>[
                    Expanded(
                        child: TextField(
                      style: TextStyle(color: Colors.black),
                      controller: myController,
                      maxLines: 5,
                      keyboardType: TextInputType.multiline,
                    )),
                    SizedBox(width: 15),
                    InkWell(
                        onTap: () {
                          _addComment();
                        },
                        child: Icon(Icons.send))
                  ]),
              SizedBox(height: 10),
              Expanded(
                  child: ListView.builder(
                      itemCount: _items.length,
                      itemBuilder: (BuildContext ctxt, int index) {
                        return Padding(
                            padding: EdgeInsets.all(10),
                            child: Text("${(index + 1)}. " + _items[index]));
                      }))
            ])));
  }
}

提交表单时如何使用ListView.builder输出小部件

1 个答案: