How to limit user input in text field flutter-CodePudding

I have a text field where I want to limit the user input for a range. e.g. I want the day of the month input in the text field so it should be limited for the range 1 - 31. How can I achieve this in the text field? I can't find any argument to set this.

CodePudding user response：

For the day of month, you can use regular expression

TextFormField(
          inputFormatters: <TextInputFormatter>[
            FilteringTextInputFormatter.allow(RegExp("^(3[01]|[12][0-9]|[1-9])\$")),
        ],
      ),

Demo

CodePudding user response：

TextEditingController _controller = new TextEditingController();
String text = ""; 
int maxLength = 2;
new TextField(
    keyboardType: TextInputType.number,
    controller: _controller,
    onChange: (String newVal) {
        var num = int.parse(newVal);
        if(newVal.length <= maxLength && num > 0 && num < 32){
            text = newVal;
        }else{
            _controller.value = new TextEditingValue(
                text: text,
                selection: new TextSelection(
                    baseOffset: maxLength,
                    extentOffset: maxLength,
                    affinity: TextAffinity.downstream,
                    isDirectional: false
                ),
                composing: new TextRange(
                    start: 0, end: maxLength
                )
            );
            _controller.text = text;
        } 
    }
);

CodePudding user response：

please try this

new TextFormField(
  validator: (value) {
    if (value==null) {
      return '* Please enter Contact No.';
    }else if (value.length>10||value.length<10){
      return '* Phone number must be 10 digit';
    }
    return null;
  },
  style: formText,
  maxLength: 10,
  controller: _primaryContactController,
  keyboardType: TextInputType.phone,
  decoration: LeadInputDecoration.textFieldStyle(
      labelTextStr: 'Contact No.'),
)