how to set initial value to dropdown menu in flutter?

Question

how to set initial value to dropdown menu in flutter?

In dropdown menu I want to set initial value, currently its showing hint value "Select Language". I need the initial value to show there. Like my initial value is English, that should be the selected item in my Dropdown menu.

below is my code:

new DropdownButtonHideUnderline(

               child: new DropdownButton<Language>(
                 hint: new Text("Select Language"),
                 value: selectedLanguage,
                 onChanged: (Language newValue) {
                   applic.onLocaleChanged(new Locale(newValue.languageCode,''));
                   setState(() {
                     selectedLanguage = newValue;
                   });
                 },
                 items: listLanguage.map((Language language) {
                   return new DropdownMenuItem<Language>(
                     value: language,
                     child: new Text(

                       language.languageName ,
                       style: new TextStyle(color: Colors.black),
                     ),
                   );
                 }).toList(),
               ),
             )

my list is initialized as:

List<Language> listLanguage =
  <Language> [new Language("English", "en"),
  new Language("French", "fr"),
  new Language("Hindi", "hi"),

  ];

 Language selectedLanguage;

Answer 1

For the dropdown to be able to recognize which languages are equal, you need to implement operator== and hashCode:

class Language {
  final String code;
  final String name;

  const Language(this.name, this.code);

  int get hashCode => code.hashCode;

  bool operator==(Object other) => other is Language && other.code == code;
}

at least if you don't use const like

const Language("English", "en"),

or reuse a previously created instance

selectedLanguage = listLanguage[0];

because without operator== or const

selectedLanguage = new Language("English", "en");

will point to an entirely different Language instance as these in listLanguage where the dropdown has now way knowing they should be recognized as the same.