我在flutter中使用了TextFormField。我想验证TextFormField,它的值应该小于100,或者应该单独是字符'a‘
我试过了
validator: (value) {
if (value.length == 0 ) {
return ('value is required!');
}
else if(value != "a" || value != "A" || in
我正在使用VS代码在flutter中设置一个TextField小部件,我在TextFormField上得到了这个错误:
No Material widget found.
TextField widgets require a Material widget ancestor.
I/flutter ( 3827): In material design, most widgets are conceptually "printed" on a sheet of material. In Flutter's
I/flutter ( 3827): material libr
代码:
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
class CustomTextFormField extends StatelessWidget {
final String hintText;
final Color color;
final Color fillColor;
final void Function(String?)? onSave;
final void Function(String?)? val
我正在尝试将首次按钮设置为禁用,当用户输入它被启用的金额时,按钮禁用工作正常,但当我在TextFormField中输入金额时,它给出以下错误。 I/flutter (29519): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY
╞═══════════════════════════════════════════════════════════
I/flutter (29519): The following assertion was thrown building
TextFormField(dirty, state: _T