Flutter中FormatException求助：无效日期格式致应用崩溃

现象 #

• API返回无效格式日期（如NaNNaNNa）时，应用触发FormatException崩溃
• 尝试通过try{}catch(e)捕获异常，但崩溃仍发生

崩溃栈信息 #

Fatal Exception: io.flutter.plugins.firebase.crashlytics.FlutterError: FormatException: Invalid date format
8 Apr 20. Error thrown while handling a gesture.
       at DateTime.parse(dart:core)
       at MyTravellersCtrl.loadTravellerIntoForm(my_travellers_ctrl.dart:298)
       at _MyTravellersView.build.<fn>.<fn>(my_travellers_page.dart:168)
       at _TravellersListView.build.<fn>.<fn>.<fn>(my_travellers_page.dart:752)
       at _InkResponseState.handleTap(ink_well.dart:1154)
       at GestureRecognizer.invokeCallback(recognizer.dart:275)
       at TapGestureRecognizer.handleTapUp(tap.dart:654)
       at BaseTapGestureRecognizer._checkUp(tap.dart:311)
       at BaseTapGestureRecognizer.acceptGesture(tap.dart:281)
       at GestureArenaManager.sweep(arena.dart:167)
       at GestureBinding.handleEvent(binding.dart:492)
       at GestureBinding.dispatchEvent(binding.dart:468)
       at RendererBinding.dispatchEvent(binding.dart:333)
       at GestureBinding._handlePointerEventImmediately(binding.dart:413)
       at GestureBinding.handlePointerEvent(binding.dart:376)
       at GestureBinding._flushPointerEventQueue(binding.dart:323)
       at GestureBinding._handlePointerDataPacket(binding.dart:292)

崩溃根源 #

loadTravellerIntoForm方法中使用了DateTime.parse，该方法在日期格式无效时会直接抛出FormatException；而DateTime.tryParse在格式无效时返回null，不会触发崩溃。此前formattedDate方法已正确使用tryParse处理无效日期，但loadTravellerIntoForm未同步修改。

修复方案 #

将loadTravellerIntoForm中的DateTime.parse替换为DateTime.tryParse，并处理null情况，确保无效日期时返回空字符串。

修复后代码 #

void loadTravellerIntoForm(TravellerProfile? traveller) {
  String formattedPassportExpiry = '';

  if (traveller?.passportExpiry != null &&
      traveller?.passportExpiry?.isNotEmpty == true) {
    final dateStr = traveller?.passportExpiry?.substring(0, 8) ?? '';
    final dateTime = DateTime.tryParse(dateStr);
    if (dateTime != null) {
      formattedPassportExpiry = DateFormat('dd MMM yyyy').format(dateTime);
    }
  }
  
  passportExpiryDateTextCtrl.text = formattedPassportExpiry;
  // ... 其他代码
}

优化建议：复用已有格式化逻辑 #

现有formattedDate方法已实现无效日期处理，可复用该方法统一日期格式化逻辑，避免重复代码：

void loadTravellerIntoForm(TravellerProfile? traveller) {
  String formattedPassportExpiry = '';
  // 复用formattedDate处理原始日期
  String baseFormatted = formattedDate(traveller?.passportExpiry ?? '');
  if (baseFormatted.isNotEmpty) {
    final dateTime = DateTime.tryParse(baseFormatted);
    if (dateTime != null) {
      formattedPassportExpiry = DateFormat('dd MMM yyyy').format(dateTime);
    }
  }
  
  passportExpiryDateTextCtrl.text = formattedPassportExpiry;
  // ... 其他代码
}

内容的提问来源于stack exchange，提问作者grizzzzzy