# FormatException：读取 SharedPreferences 时出现无效的十进制数字（字符 1）

- **ID:** `flutter/shared-preferences-corruption`
- **领域:** flutter
- **类别:** data_error
- **验证级别:** ai_generated
- **修复率:** 78%

## 根因

SharedPreferences（或 NSUserDefaults）中存储的值应为整数，但已损坏或保存为非数字字符串，通常是由于版本不匹配或手动编辑所致。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| Flutter 3.22 | active | — | — |
| Dart 3.4 | active | — | — |
| Android 13 | active | — | — |
| iOS 16 | active | — | — |

## 解决方案

1. ```
   Use a migration function that reads the corrupted value as a string, attempts to parse it, and if it fails, removes the key and sets a default. Example: `final raw = prefs.getString('counter'); int? value; try { value = int.parse(raw!); } catch (e) { await prefs.remove('counter'); value = 0; }`
   ```
2. ```
   Implement a versioned SharedPreferences wrapper that validates data types on read and repairs corrupted entries automatically.
   ```
3. ```
   For critical data, migrate to a more robust storage solution like Hive or Isar that includes type safety and corruption detection.
   ```

## 无效尝试

- **** — This deletes all user preferences, causing loss of user settings and potentially breaking app functionality; it's a nuclear option that should only be used as a last resort. (40% 失败率)
- **** — The corruption remains in storage and will cause the same error on every app restart; the default value may not match user expectations. (70% 失败率)
- **** — Not feasible for production apps; root access is rare and editing XML can cause further corruption or crash the app. (95% 失败率)