c 接入android的代码,在android中如何编译连接 .c 的可执行文件-优快云博客

1. 在./development目录下创建一目录如：myhello

2. 进入hello目录，在其下编写自己的.c文件,如: myhello.c

#include

int main()

{

printf("hello world\n");

exit(0);

//return 0;

}

3. 在hello目录中，编写Android.mk, 内容如下：

LOCAL_PATH:= $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE := myhelloworld

LOCAL_SRC_FILES := myhello.c

LOCAL_MODULE_TAGS := optional

include $(BUILD_EXECUTABLE)

4. 回到Android源代码顶层目录，进行编译，make myhelloworld

5. 生成的可执行文件位于:out/target/product/lotus/system/bin/ 目录下

6. adb push 到手机 /data 目录下,然后进入adb shell,到data目录下,执行./myhelloworld 皆可

手动编译连接【arm-eabi-gcc 的目录随andorid的版本而有变化，还有就是需要链接的文件如果比较多时，需要很多-l 就很麻烦了】

7、编译成目标文件：

#$(yourAndroid)/prebuilt/linux-x86/toolchain/[arm-eabi-4.2.1]/bin/arm-eabi-gcc -I bionic/libc/arch-arm/include/ -I bionic/libc/include -I bionic/libc/kernel/common -I bionic/libc/kernel/arch-arm -g -c helloworld.c -o hello.o

8、生成可执行代码：

#$(yourAndroid)/prebuilt/linux-x86/toolchain/[arm-eabi-4.2.1]/bin/arm-eabi-gcc -nostdlib -Bdynamic -Wl,-T,build/core/armelf.x -Wl,-dynamic-linker,/system/bin/linker -Wl,--gc-sections -Wl,-z,nocopyreloc -o helloworld -Lout/target/product/[generic]/obj/lib -Wl,-rpath-link=out/target/product/[generic]/obj/lib -lc hello.o -entry=main

其中[ ]中部分根据实际情况修改

**************************************************

实验：

1. 建目录(my Android)/development/test，在该目录下新建 Android.mk和fb_test.c文件

2. Android.mk文件

LOCAL_PATH:= $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE := myfbtest

LOCAL_SRC_FILES := fb_test.c

LOCAL_MODULE_TAGS := optional

include $(BUILD_EXECUTABLE)

3. 以下为fb_test.c

#include

#define FBBIT_PER_PIXEL 32

#define FBBIT_PIXEL_IMAGE 16

#define PIXELS_WIDTH_BYTE 4

#define BYTE_PER_PIXEL 3

#define FB_GRAPHICS_PATH "/dev/graphics/fb0"

#define DEV_TTY0_PATH "/dev/tty0"

#define DISPLAY_ERROR -1

#define DISPLAY_SUCCESS 0

#define GET_BATTERYCAPACITY_ERR -1

#define MAX_STR 255

static struct {

int fd;

void *pixels;

struct fb_fix_screeninfo fixed;

struct fb_var_screeninfo var;

int align_xres;

} fb;

int getBatteryCapacity(void)

{

FILE *in;

char tmpStr[MAX_STR + 1];

char capfile[] = "/sys/class/power_supply/battery/capacity";

if (capfile == NULL)

return GET_BATTERYCAPACITY_ERR;

in = fopen(capfile, "rt");

if (in == NULL)

return GET_BATTERYCAPACITY_ERR;

if (fgets(tmpStr, MAX_STR, in) == NULL) {

printf("Failed to read battery capacity!\n");

fclose(in);

return GET_BATTERYCAPACITY_ERR;

}

printf("Battery capacity(ascii): %s\n", tmpStr);

fclose(in);

return 0;//atoi(tmpStr);

}

static int vt_set_graphicsmode(int graphics)

{

int fd, r;

fd = open(DEV_TTY0_PATH, O_RDWR | O_SYNC);

if (fd < 0)

return DISPLAY_ERROR;

r = ioctl(fd, KDSETMODE, graphics);

close(fd);

return r;

}

int display_init(void)

{

fb.fd = open(FB_GRAPHICS_PATH, O_RDWR);

if (fb.fd < 0)

return DISPLAY_ERROR;

if (ioctl(fb.fd, FBIOGET_FSCREENINFO, &fb.fixed) < 0)

return DISPLAY_ERROR;

if (ioctl(fb.fd, FBIOGET_VSCREENINFO, &fb.var) < 0)

return DISPLAY_ERROR;

fb.align_xres = fb.fixed.line_length /

(fb.var.bits_per_pixel >> BYTE_PER_PIXEL);

fb.pixels = mmap(0, fb.fixed.line_length * fb.var.yres_virtual,

PROT_READ | PROT_WRITE, MAP_SHARED, fb.fd, 0);

if (fb.pixels == MAP_FAILED)

return DISPLAY_ERROR;

vt_set_graphicsmode(KD_GRAPHICS);

memset(fb.pixels, 0, fb.fixed.line_length * fb.var.yres_virtual);

//display_update(fb.pixels, fb.align_xres, fb.var.yres);

fb.var.activate = FB_ACTIVATE_FORCE;

ioctl(fb.fd, FBIOPUT_VSCREENINFO, &fb.var);

printf("display_init ok\n");

return DISPLAY_SUCCESS;

}

void display_on(void)

{

ioctl(fb.fd, FBIOBLANK, FB_BLANK_UNBLANK);

}

void display_off(void)

{

ioctl(fb.fd, FBIOBLANK, FB_BLANK_POWERDOWN);

}

int main()

{

display_init();

display_off();//关显示屏

getBatteryCapacity();

sleep(5);

display_on();//开显示屏

return 0;

}