validators.dart 619 B

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  1. class Validators {
  2. Validators._();
  3. static String? required(String? value) {
  4. if (value == null || value.trim().isEmpty) return '此项为必填';
  5. return null;
  6. }
  7. static String? amount(String? value) {
  8. if (value == null || value.trim().isEmpty) return '请输入金额';
  9. final amount = double.tryParse(value);
  10. if (amount == null) return '请输入有效金额';
  11. if (amount <= 0) return '金额必须大于0';
  12. return null;
  13. }
  14. static String? maxLength(String? value, int max) {
  15. if (value != null && value.length > max) return '最多输入$max个字符';
  16. return null;
  17. }
  18. }