flutter type_error ai_generated true

type 'List<dynamic>' is not a subtype of type 'List<String>' in type cast

ID: flutter/invalid-runtime-type-cast

Also available as: JSON · Markdown · 中文

95%Fix Rate

90%Confidence

1Evidence

2023-02-01First Seen

Version Compatibility

Version	Status	Introduced	Deprecated	Notes
2.17.0	active	—	—	—
3.0.0	active	—	—	—
3.13.0	active	—	—	—
3.22.0	active	—	—	—

Casting a decoded JSON list directly to `List<String>` without explicit type checking; JSON decode returns `List<dynamic>`.

generic

在未进行显式类型检查的情况下，直接将解码后的 JSON 列表转换为 `List<String>`；JSON 解码返回 `List<dynamic>`。

95% success Use `List<String>.from()` or `jsonDecode(data).cast<String>().toList()` to safely convert with type checking.
```
Use `List<String>.from()` or `jsonDecode(data).cast<String>().toList()` to safely convert with type checking.
```
90% success Decode with explicit type using `jsonDecode` and then iterate to filter or convert each element.
```
Decode with explicit type using `jsonDecode` and then iterate to filter or convert each element.
```
85% success Use a JSON serialization library like `json_serializable` with proper model classes to avoid raw casts.
```
Use a JSON serialization library like `json_serializable` with proper model classes to avoid raw casts.
```

Use `List<String>.from()` or `jsonDecode(data).cast<String>().toList()` to safely convert with type checking.

Decode with explicit type using `jsonDecode` and then iterate to filter or convert each element.

Use a JSON serialization library like `json_serializable` with proper model classes to avoid raw casts.

Common approaches that don't work:

30% fail
If any element is not a String, `cast()` throws a runtime error; does not handle mixed types.
50% fail
Type cast fails at runtime; app crashes when the list is accessed.
20% fail
Swallows the error but the list remains untyped; subsequent operations may fail silently.