Answers for "password and confirm password validation in flutter"

show password in flutter

TextFormField(
   keyboardType: TextInputType.text,
   controller: _userPasswordController,
   obscureText: !_passwordVisible,//This will obscure text dynamically
   decoration: InputDecoration(
       labelText: 'Password',
       hintText: 'Enter your password',
       // Here is key idea
       suffixIcon: IconButton(
            icon: Icon(
              // Based on passwordVisible state choose the icon
               _passwordVisible
               ? Icons.visibility
               : Icons.visibility_off,
               color: Theme.of(context).primaryColorDark,
               ),
            onPressed: () {
               // Update the state i.e. toogle the state of passwordVisible variable
               setState(() {
                   _passwordVisible = !_passwordVisible;
               });
             },
            ),
          ),
        );

Password validator dart

bool isPasswordCompliant(String password, [int minLength = 8]) {
  if (password == null || password.length < minLength) {
    return false;
  }

  bool hasUppercase = password.contains(RegExp(r'[A-Z]'));
  if (hasUppercase) {
    bool hasDigits = password.contains(RegExp(r'[0-9]'));
    if (hasDigits) {
      bool hasLowercase = password.contains(RegExp(r'[a-z]'));
      if (hasLowercase) {
        bool hasSpecialCharacters = password.contains(RegExp(r'[!@#$%^&*(),.?":{}|<>]'));
        return hasSpecialCharacters;
      }
    }
  }

  return false;
}

show password in flutter

@override
  void initState() {
    _passwordVisible = false;
  }