Flutter TextField value always uppercase & debounce

Question

I am new in Flutter. I am looking for TextField value to always uppercase but I did not find any resource on that.

Another issue is the TextField onChanged event debounce implementation. When I type on TextField it immediately fires onChanged event which is not suitable for my goal. The onChange event will fire after 500ms on every text changed.

 new TextField(
         controller: _controller,
         decoration: new InputDecoration(
              hintText: 'Search here',
         ),
         onChanged: (str) {
            //need to implement debounce
         }
)

Answer 1

Works on Android, iOS, Web, macOS, Windows and Linux

You can implement a custom TextInputFormatter

class UpperCaseTextFormatter extends TextInputFormatter {
  @override
  TextEditingValue formatEditUpdate(TextEditingValue oldValue, TextEditingValue newValue) {
    return TextEditingValue(
      text: newValue.text.toUpperCase(),
      selection: newValue.selection,
    );
  }
}

---

Usage:

TextField(
  inputFormatters: [
    UpperCaseTextFormatter(),
  ]
)

Full example

Answer 2

Perhaps using textCapitalization: TextCapitalization.characters in the TextField could help you? Although this would capitalize the characters while something is being typed as well.

TextField(
    textCapitalization: TextCapitalization.sentences,
)

Answer 3

You can use textCapitalization property of a TextField widget. Also do take a reference for detailed API info here Text Capitalization Official API

Illustration as follow

Example 1

 TextField(
        initialValue: flutter code camp
        textCapitalization: TextCapitalization.characters,
    )// OUTPUT : FLUTTER CODE CAMP

Example 2

 TextField(
        initialValue: flutter code camp
        textCapitalization: TextCapitalization.words,
    )// OUTPUT : Flutter Code Camp

Example 3

 TextField(
        initialValue: flutter code camp
        textCapitalization: TextCapitalization.sentences,
    )// OUTPUT : Flutter code camp

Example 4

 TextField(
        initialValue: flutter code camp
        textCapitalization: TextCapitalization.none,
    )// OUTPUT : flutter code camp