Question

我正在移植Box2D以了解更多有关Android移植的信息。

我可以编译项目，我看到以下内容......

ls libs /

armeabi armeabi-v7a

现在我想做this之类的事情，但我不知道如何让它足够智能选择拱门（比方说我想添加x86）。如何在没有硬编码规范拱的.so路径的情况下包含.so？

Answer 1

如NDK文档（APPLICATION-MK.html和PREBUILTS.html）中所述，只需在android.mk和Application.mk中定义您想要支持的体系结构：

诉ABI选择预建二进制文件：

如前所述，提供预建的共享库至关重要   在构建期间与目标ABI兼容。要做到这一点，   检查TARGET_ARCH_ABI的值，其值为：

armeabi =＆gt;当针对ARMv5TE或更高CPU的armeabi-v7a时   =＆GT;当针对ARMv7或更高CPU时x86 =＆gt;当定位x86 CPU时mips =＆gt;何时针对MIPS CPU

请注意，armeabi-v7a系统可以正常运行armeabi二进制文件。

以下是我们提供两个版本的预构建库的示例   并根据目标ABI选择要复制的那个：
include $(CLEAR_VARS)
LOCAL_MODULE := foo-prebuilt
LOCAL_SRC_FILES := $(TARGET_ARCH_ABI)/libfoo.so
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include
include $(PREBUILT_SHARED_LIBRARY)
下面。我们假设要复制的预构建库是在以下目录层次结构：
Android.mk            --> the file above
armeabi/libfoo.so     --> the armeabi prebuilt shared library
armeabi-v7a/libfoo.so --> the armeabi-v7a prebuilt shared library
include/foo.h         --> the exported header file
注意：请记住，您不需要提供armeabi-v7a预建库，因为armeabi可以很容易地运行相应的设备

Answer 2

这有效......

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := box2D-prebuilt
LOCAL_SRC_FILES := ../Box2D/libs/$(TARGET_ARCH_ABI)/libbox2D.so
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/..
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE    := box2DHello
LOCAL_SRC_FILES := \
    $(subst $(LOCAL_PATH)/,, \
    $(wildcard $(LOCAL_PATH)/*.cpp))
LOCAL_LDLIBS := -lm -llog
LOCAL_SHARED_LIBRARIES := box2D-prebuilt
include $(BUILD_SHARED_LIBRARY)

Answer 3

任何寻找有关任何android.mk问题的好文档的人都可以参考：

https://github.com/Parrot-Developers/alchemy/blob/master/doc/android-mk.html

我发现它用简单的单词解释得非常好，涵盖了围绕Android.mk的大部分场景。希望它有所帮助。

Answer 4

Android NDK官方hello-libs CMake示例

https://github.com/googlesamples/android-ndk/tree/840858984e1bb8a7fab37c1b7c571efbe7d6eb75/hello-libs

关键是要打包您关注的.so的所有版本，例如：

distribution/gperf/lib/arm64-v8a/libgperf.so
distribution/gperf/lib/x86_64/libgperf.so

然后在CMake上选择正确的：${ANDROID_ABI}。

我在How to link a prebuilt shared Library to an Android NDK project?

进一步解释了这个例子

Answer 5

libmath-prebuilt.so是一个预建的库，它有一些由buyya_read.c使用的函数。首先使用ndk-build生成libmath-prebuilt.so并保存在jni文件夹中，其中buyya_read.c保存在elcipse中的ur项目中。

Android.mk(To generate libbuyya_read.so to use as jni library using prebuilt library)
    LOCAL_PATH := $(call my-dir)
    include $(CLEAR_VARS)
    LOCAL_MODULE := math-prebuilt
    LOCAL_SRC_FILES = libmath-prebuilt.so
    include $(PREBUILT_SHARED_LIBRARY)

    include $(CLEAR_VARS)
    LOCAL_MODULE    := buyya_read
    LOCAL_SRC_FILES := buyya_read.c
    LOCAL_LDLIBS    := -llog
    LOCAL_SHARED_LIBRARIES := math-prebuilt
    include $(BUILD_SHARED_LIBRARY)

buyya_read.c
#include <termios.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <jni.h>
#include <stdio.h>

JNIEXPORT jint JNICALL Java_com_buyya_BuyyaJava_sum(JNIEnv *env,
    jclass thiz, jint a, jint b) {
hello();
int res = add(a, b);
return res;
}

math.c // using this generate libmath-prebuilt.so
#include <stdio.h>
void hello()
{
    printf("Hello world!\n");
}
int add(int a, int b)
{
    printf("Hello world!\n");
    return a+b;
}

Make file to generate libmath-prebuilt.so
Android.mk
    LOCAL_PATH := $(call my-dir)
    include $(CLEAR_VARS)
    LOCAL_MODULE    := math-prebuilt
    LOCAL_SRC_FILES := math.c
    LOCAL_LDLIBS    := -llog
    #LOCAL_EXPORT_C_INCLUDES:=../jni/
    include $(BUILD_SHARED_LIBRARY)

您可以在下图中看到项目目录结构。

NDK：如何包含预建的共享库，无论架构如何

5 个答案:

诉ABI选择预建二进制文件：