2016-04-25

AndroidNDK

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CrystaX NDK

Boost + Android? CrystaX NDK!
使用Android Studio构建基于NDK和Boost C++库的应用程序

不错的 ndk 文章

Android ndk入门学习
 JNI系列教程三 —— NDK入门
 MENU Android Studio中NDK开发
 Android Studio, gradle and NDK integration
NDK-JNI实战教程(一) 在Android Studio运行第一个NDK程序
 NDK-JNI实战教程(二) JNI官方中文资料
 Android Studio ndk-Jni开发详细入门,Aes加密demo
国外不错的文章-The new NDK support in Android Studio

出现错误

 /home/user5432/workspace/bitmapproj/obj/local/armeabi/objs-debug/mybitmap.o : In function Java_com_example_plasma_PlasmaView_renderPlasma
"undefined reference to AndroidBitmap_getInfo"
"undefined reference to AndroidBitmap_lockPixels"
"undefined reference to AndroidBitmap_unlockPixels"

gradle ndk 添加如下依赖

1
2
3

ndk {
    ldLibs "log","android", "jnigraphics" // 引用依赖的 ndk 库 ldLibs = ["android", "jnigraphics", <other ndk libraries you might need>]
}

或 Android.mk 添加如下依赖

1	`LOCAL_LDFLAGS += -ljnigraphics`

参考
Android bitmap native code - linking problem

出现 NEON 错误

1	Error:(31, 2) error: #error You must enable NEON instructions (e.g. -mfloat-abi=softfp -mfpu=neon) to use arm_neon.h

Android NDK(ARM开发)使用NEON优化
 Android NDK使用NEON优化,SIMD优化
 Gradle - neon
How do I enable ARM NEON builds using Gradle?
How to build and debug native code (c) with neon enabled in android studio?
Android-NDK _NEON Support

error Unknown or unsupported ARM architecture

[revamp] Android NDK API 21 issue #455

It would appear that at least as of Kitkat 4.4 (API 19), ARM devices are required to be at least ARMv7a:

MUST report, via android.os.Build.CPU_ABI, only one of the ABIs listed below
* armeabi-v7a
* x86
* mips
It's not altogether surprising that the API to follow 19 (Lollipop API 21) would drop support for ARMv5 completely. From what I've read, official builds of 4.4+ are always ARMv7a, but there are some custom builds for certain devices which run ARMv6.

So the fix is to target a lower API or target the armeabi-v7a architecture. Switching to v7a fixed this problem for me.

我的错误信息大概是 android-23/…/cpu-feature.h 中的错误,可能是最新的 ndk 暂不支持 cpu-feature.h 的 armeabi 平台编译库吧, 去掉 abiFilters 中的 armeabi 编译选项即可

1	abiFilters "armeabi-v7a" , "x86", "mips" //"armeabi", "armeabi-v7a" , "x86"

错误 Error:(208, 9) error: ‘for’ loop initial declarations are only allowed in C99 or C11 mode

C:\Users\yafei\AppDeveloperWorkspace\CoamAndroid\app\src\main\jni\audio.c
Error:(208, 9) error: 'for' loop initial declarations are only allowed in C99 or C11 mode
Information:(208, 9) use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
C:\Users\yafei\AppDeveloperWorkspace\CoamAndroid\app\src\main\jni\audio.c: In function 'Java_com_coam_ui_telegram_controller_TelegramMediaController_getWaveform2':
C:\Users\yafei\AppDeveloperWorkspace\CoamAndroid\app\src\main\jni\audio.c:692:5: error: 'for' loop initial declarations are only allowed in C99 or C11 mode