android 使用uinput模拟输入设备的方法

在google remote中，android接收端接收socket发来的IR CODE，然后将IR CODE模拟出来发给系统处理，这就是google remote接收端的原理。

系统端怎样模拟input event呢？
方法一：通过Instrumentation.sendKeyDownUpSync 实现，简单使用但是问题在于sendKeyDownUpSync发出的event，无法运行到
interceptKeyBeforeDispatching，也就无法正常作用 HOME，VOL...
方法二：通过uinput桥接；原理是利用内核现有的uinput驱动，通过内核驱动uinput来发送input event，而且还容易使用kl,kcm 客制化；

经过比较方法二较优，下面就就给出方法二的测试代码...
  1、main函数，setup_uinput_device 完成设备的注册，然后创建一个线程 VirtualInputDev_EventThread，该线程重复发出keycode；

代码如下:

int main()
{

printf("Enter process !!!! \n");

stVirtualInputDevData *pKpdData = (stVirtualInputDevData*) malloc(sizeof(stVirtualInputDevData));
   pKpdData->min_keycode = umin_keycode;
   pKpdData->max_keycode = umax_keycode;
    if (setup_uinput_device(pKpdData) < 0) {
        printf("Unable to find uInput device\n");
        free(pKpdData);
        return -1;
    }

pthread_attr_t attr;
    pthread_attr_init(&attr);
    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
    if (0 != pthread_create(&keypad_EventThreadId, &attr, VirtualInputDev_EventThread, (void *)0)) {
        printf("Create KeypadEventThread Failed!!\n");
        exit(1);
    }

// Coverity server need set to ignore this.
    while (1) {
        usleep(1000000);  // sleep 1 second
    }

free(pKpdData);
    pKpdData = 0;

// Destroy the device
    ioctl(uinp_fd, UI_DEV_DESTROY);

close(uinp_fd);
    return 0;
}

2、setup_uinput_device函数，完成设备注册；可以看到是直接打开uinput节点，设置了虚拟设备的name，verdor，product，bustype，
   最后通过ioctl(uinp_fd, UI_DEV_CREATE)注册设备

代码如下:

int setup_uinput_device(stVirtualInputDevData* mstVirtualInputDevData)
{
    struct uinput_user_dev uinp; // uInput device structure
    int i;

// Open the input device
    uinp_fd = open("/dev/uinput", O_WRONLY | O_NDELAY);
    if (uinp_fd == 0) {
        printf("Unable to open /dev/uinput\n");
        return -1;
    }

// Intialize the uInput device to NULL
    memset(&uinp, 0x00, sizeof(uinp));
    strncpy(uinp.name, "virtualinputdev", sizeof(uinp.name)-1);
    uinp.id.vendor = 0x1341;
    uinp.id.product = 0x0001;
    uinp.id.bustype = BUS_VIRTUAL;

// Keyboard
    ioctl(uinp_fd, UI_SET_EVBIT, EV_KEY);
    for (i = mstVirtualInputDevData->min_keycode; i < mstVirtualInputDevData->max_keycode; i++) {
        ioctl(uinp_fd, UI_SET_KEYBIT, i);
    }

// Create input device into input sub-system
    if (write(uinp_fd, &uinp, sizeof(uinp)) != sizeof(uinp)) {
        printf("First write returned fail.\n");
        return -1;
    }

if (ioctl(uinp_fd, UI_DEV_CREATE)) {
        printf("ioctl UI_DEV_CREATE returned fail.\n");
        return -1;
    }

return 1;
}

3、线程 VirtualInputDev_EventThread，只是重复发key，发key是通过write_event_to_device来完成的

代码如下:

static void* VirtualInputDev_EventThread(void *driver_data)
{

unsigned char u8Keycode,i=umin_keycode;

while (1) {
        u8Keycode = 0xff;

/* sleep an interval time */
        usleep(2000000);//sleep 5 s
        /* fill event to uinput device. */
        write_event_to_device(i++, 0);
  if(i==4){
  i = 0;
  }
  printf ("virtualinputdev thread ...\n");
  //i %= umax_keycode;
    }

printf ("virtualinputdev thread died\n");
    pthread_exit(0);
    return 0;
}

4、write_event_to_device 写event到uinput节点

代码如下:

void write_event_to_device(unsigned char u8KeyCode, unsigned char u8Repeat)
{
    struct input_event event; // Input device structure
    struct timespec s;
    s.tv_nsec = 5000000L;
    s.tv_sec = 0;

memset(&event, 0x00, sizeof(event));
    gettimeofday(&event.time, 0);
    event.type = EV_KEY;
    event.code = u8KeyCode;
    event.value = 1;
    write(uinp_fd, &event, sizeof(event));

memset(&event, 0x00, sizeof(event));
    gettimeofday(&event.time, 0);
    event.type = EV_KEY;
    event.code = u8KeyCode;
    event.value = 0;
    write(uinp_fd, &event, sizeof(event));

memset(&event, 0x00, sizeof(event));
    gettimeofday(&event.time, 0);
    event.type = EV_SYN;
    event.code = SYN_REPORT;
    event.value = 0;
    write(uinp_fd, &event, sizeof(event));
}