Flutter - Create dynamic number of texteditingcontrollers

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April 2019

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1

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?

2 answers

2

More or less as @Günter Zöchbauer mentioned, you can just build a list of widgets which are nested then in a container.

Here's a simple example:

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
    var textEditingControllers = <TextEditingController>[];

    var textFields = <TextField>[];
    stringListReturnedFromApiCall.forEach((str) {
      var textEditingController = new TextEditingController(text: str);
      textEditingControllers.add(textEditingController);
      return textFields.add(new TextField(controller: textEditingController));
    });

    return Scaffold(
        appBar: AppBar(
          title: Text(widget.title),
        ),
        body: SingleChildScrollView(
            child: new Column(
          children: textFields,
        )));
  }
}

Edit: Added list for TextEditingControllers to interact with all the TextFields

1

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 .......