Flutter - Create dynamic number of texteditingcontrollers

Question

I am recreating an app I have previously made in Swift, and on one of my pages we call an API and based on the results, we present the user a dynamic number of textfields to search by different search parameters.

Is there any good way to do this in Dart/Flutter? Since dart doesn't support generating code at runtime, is this even a possibility?

Answer 1

Using list of textEditingControllers instead of map

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  var stringListReturnedFromApiCall = ["first", "second", "third", "fourth", "..."];
  List<TextEditingController> textEditingControllers = [];

  @override
  void initState() {
    super.initState();
    stringListReturnedFromApiCall.forEach((String str) {
      var textEditingController = TextEditingController(text: str);
      textEditingControllers.add(textEditingController);
    });
  }

  @override
  void dispose() {
    super.dispose();
    // dispose textEditingControllers to prevent memory leaks
    for (TextEditingController textEditingController in textEditingControllers) {
      textEditingController?.dispose();
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('title'),
      ),
      body: ListView.builder(
        itemCount: stringListReturnedFromApiCall.length,
        itemBuilder: (BuildContext context, int index) {
          return Padding(
            padding: const EdgeInsets.all(10.0),
            child: TextField(
              controller: textEditingControllers[index],
            ),
          );
        },
      ),
    );
  }
}

Answer 2

I just modified @Felix's answer with using Map to store TextEditingControllers instead of list. I think its easy to call textEditingControllers with key value pairs. Modified code block;

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "MyHomePage",
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(
        title: "MyHomePage",
      ),
    );
  }
}
class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {

  @override
  Widget build(BuildContext context) {
    var stringListReturnedFromApiCall = ["first", "second", "third", "fourth", "..."];
    // This list of controllers can be used to set and get the text from/to the TextFields
    Map<String,TextEditingController> textEditingControllers = {};
    var textFields = <TextField>[];
    stringListReturnedFromApiCall.forEach((str) {
      var textEditingController = new TextEditingController(text: str);
      textEditingControllers.putIfAbsent(str, ()=>textEditingController);
      return textFields.add( TextField(controller: textEditingController));
    });

    return Scaffold(
        appBar: AppBar(
          title: Text(widget.title),
        ),
        body: SingleChildScrollView(
            child: new Column(
              children:[
              Column(children:  textFields),
                RaisedButton(
                  child: Text("Print Values"),
                    onPressed: (){
                    stringListReturnedFromApiCall.forEach((str){
                      print(textEditingControllers[str].text);
                    });
                  })
              ]
            )));
  }
}

when you write something to textfields and hit to print button results ;

flutter: first controller text
flutter: second controller text
flutter: third controller text
flutter: fourth controller text
flutter: so on .......