# CMake错误在/path/to/android-ndk-r26c/build/cmake/android.toolchain.cmake:XX (message): 未知ABI: arm64-v8a-hard

- **ID:** `android/ndk-cmake-unknown-abi`
- **领域:** android
- **类别:** build_error
- **验证级别:** ai_generated
- **修复率:** 93%

## 根因

NDK r26c移除了对'arm64-v8a-hard' ABI变体（具有硬件浮点优化）的支持，转而使用标准'arm64-v8a'。仍指定'-hard'后缀的项目在build.gradle或CMakeLists.txt中导致此错误。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| Android NDK r26c | active | — | — |
| Android NDK r25b | active | — | — |
| CMake 3.22.1 | active | — | — |
| Gradle 8.5 | active | — | — |

## 解决方案

1. ```
   Change build.gradle ndk.abiFilters to use 'arm64-v8a' instead of 'arm64-v8a-hard'. Example: defaultConfig { ndk { abiFilters 'arm64-v8a', 'x86_64' } }
   ```
2. ```
   Update CMakeLists.txt to remove any -hard suffix from target_compile_options or set(CMAKE_ANDROID_ARM_MODE ARM) to ensure soft-float is used. Then clean rebuild.
   ```

## 无效尝试

- **Set ANDROID_ABI=arm64-v8a-hard in gradle.properties** — NDK r26c no longer recognizes this ABI string. Setting it in properties just passes the same invalid value to CMake. (95% 失败率)
- **Downgrade NDK to r25b** — This works temporarily but prevents using newer NDK features and security patches. Also breaks if other libraries require r26c. (60% 失败率)