Android jni開發中的常見錯誤

錯誤1：java.lang.UnsatisfiedLinkError: Native method not found: 本地方法沒有找到

1、本地函數名寫錯

2、忘記載入.so文件 沒有調用System.loadlibrary

錯誤2：findLibrary returned null

1、System.loadLibrary("libhello"); 載入動態鏈接庫時 動態鏈接庫名字寫錯

2、平臺類型錯誤 把只支持arm平臺的.so文件部署到了 x86cpu的設備上

查看幫助文檔：

APP_ABI

By default, the NDK build system will generate machine code for the 'armeabi' ABI. This corresponds to an ARMv5TE based CPU with software floating point operations. You can use APP_ABI to select a different ABI.

For example, to support hardware FPU instructions on ARMv7 based devices, use:

          APP_ABI := armeabi-v7a

Or to support the IA-32 instruction set, use:

          APP_ABI := x86

Or to support the MIPS instruction set, use:

          APP_ABI := mips

Or to support all at the same time, use:

          APP_ABI := armeabi armeabi-v7a x86 mips

Or even better, since NDK r7, you can also use the special value 'all' which means "all ABIs supported by this NDK release":

          APP_ABI := all

For the list of all supported ABIs and details about their usage and limitations, please read CPU-ARCH-ABIS.

在jni目錄下創建 Application.mk 在裡面指定

APP_ABI := armeabi x86

重新編譯後可以看到分成兩個平臺編譯，生成2個.so文件

我們可以看到上面的編譯過程中出現警告，可以在 Application.mk 指定：
APP_PLATFORM := android-8