Ⅰ 如何生成唯一的Android設備ID
Android的開發者在一些特定情況下都需要知道手機中的唯一設備ID。例如，跟蹤應用程序的安裝，生成用於復制保護的DRM時需要使用設備的唯一ID。
范圍
本文提供有關如何讀取各種Android設備的 ID的介紹，用以使用標識號。本文假定用戶已經安裝了Android以及開發應用程序必要的工具。並且，本文假定用戶已了解Android的基本知識。
簡介在搭載Android操作系統的設備中，已經存在好幾種類型的設備標識號。先前的所有Android設備都具有電話功能，因此查找每部設備硬體唯一的IMEI，MEID，或ESN也很容易。但僅能使用Wifi的設備或音樂播放器沒有電話硬體，所以沒有這種類型的唯一標識號。本文闡述了如何讀取不同Android設備的標識號。檢索Android設備ID各種方式
Ⅱ android下設備節點在什麼位置
/dev下面
Ⅲ Android 是如何動態管理dev下的設備節點的
內核中的每個設備添加到系統都會發送一個uevent，運行在用戶空間的udev會檢測到這個event，event中會有設備的主次設備號等內容，udev根據event的內容做相應的動作，創建設備，刪除設備等。 在Android中，沒有獨立的類似與udev或者mdev的用戶程序，這個功能集成到了init中做了。 代碼見: system/core/init/init.c if (ufds[0].revents == POLLIN) handle_device_fd(device_fd); void handle_device_fd(int fd){char msg[UEVENT_MSG_LEN 2];int n; while((n = recv(fd, msg, UEVENT_MSG_LEN, 0)) 0) { struct uevent uevent; if(n == UEVENT_MSG_LEN) /* overflow -- discard */continue; msg[n] = '\0'; msg[n 1] = '\0';
Ⅳ Android怎麼生成設備節點
Android如何生成設備節點
在Android中，由於沒有mdev和udev，所以它沒有辦法動態的生成設備節點，那麼它是如何做的呢？
我們可以在system/core/init/下的init.c和devices.c中找到答案：
init.c中
int main(int argc, char **argv)
{
...
/* Get the basic filesystem setup we need put
* together in the initramdisk on / and then we'll
* let the rc file figure out the rest.
*/
mkdir("/dev", 0755);
mkdir("/proc", 0755);
mkdir("/sys", 0755);
mount("tmpfs", "/dev", "tmpfs", 0, "mode=0755");
mkdir("/dev/pts", 0755);
mkdir("/dev/socket", 0755);
mount("devpts", "/dev/pts", "devpts", 0, NULL);
mount("proc", "/proc", "proc", 0, NULL);
mount("sysfs", "/sys", "sysfs", 0, NULL);
for(;;) {
...
if (ufds[0].revents == POLLIN)
handle_device_fd(device_fd);
if (ufds[1].revents == POLLIN)
handle_property_set_fd(property_set_fd);
if (ufds[3].revents == POLLIN)
handle_keychord(keychord_fd);
}
return 0;
}
我們再來看看handle_device_fd()，該函數定義在devices.c中
void handle_device_fd(int fd)
{
...
handle_device_event(&uevent);
handle_firmware_event(&uevent);
}
}
而handle_device_event定義如下：
static void handle_device_event(struct uevent *uevent)
{
...
if(!strcmp(uevent->action, "add")) {
make_device(devpath, block, uevent->major, uevent->minor);
return;
}
...
}
make_device定義如下：
static void make_device(const char *path, int block, int major, int minor)
{
...
mode = get_device_perm(path, &uid, &gid) | (block S_IFBLK : S_IFCHR);
dev = (major $amp; ...
setegid(gid);
mknod(path, mode, dev);
chown(path, uid, -1);
setegid(AID_ROOT);
}
我們看看get_device_perm如下實現：
static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
{
mode_t perm;
if (get_device_perm_inner(qemu_perms, path, uid, gid, &perm) == 0) {
return perm;
} else if (get_device_perm_inner(devperms, path, uid, gid, &perm) == 0) {
return perm;
} else {
struct listnode *node;
struct perm_node *perm_node;
struct perms_ *dp;
/* Check partners list. */
list_for_each(node, &devperms_partners) {
perm_node = node_to_item(node, struct perm_node, plist);
dp = &perm_node->dp;
if (dp->prefix) {
if (strncmp(path, dp->name, strlen(dp->name)))
continue;
} else {
if (strcmp(path, dp->name))
continue;
}
/* Found perm in partner list. */
*uid = dp->uid;
*gid = dp->gid;
return dp->perm;
}
/* Default if nothing found. */
*uid = 0;
*gid = 0;
return 0600;
}
}
我們最後可以看到在devperms中定義了要生成的設備節點：
static struct perms_ devperms[] = {
{ "/dev/null", 0666, AID_ROOT, AID_ROOT, 0 },
{ "/dev/zero", 0666, AID_ROOT, AID_ROOT, 0 },
{ "/dev/full", 0666, AID_ROOT, AID_ROOT, 0 },
{ "/dev/ptmx", 0666, AID_ROOT, AID_ROOT, 0 },
{ "/dev/tty", 0666, AID_ROOT, AID_ROOT, 0 },
{ "/dev/random", 0666, AID_ROOT, AID_ROOT, 0 },
{ "/dev/urandom", 0666, AID_ROOT, AID_ROOT, 0 },
{ "/dev/ashmem", 0666, AID_ROOT, AID_ROOT, 0 },
{ "/dev/binder", 0666, AID_ROOT, AID_ROOT, 0 },
/* logger should be world writable (for logging) but not readable */
{ "/dev/log/", 0662, AID_ROOT, AID_LOG, 1 },
/* the msm hw3d client device node is world writable/readable. */
{ "/dev/msm_hw3dc", 0666, AID_ROOT, AID_ROOT, 0 },
/* gpu driver for adreno200 is globally accessible */
{ "/dev/kgsl", 0666, AID_ROOT, AID_ROOT, 0 },
/* these should not be world writable */
{ "/dev/diag", 0660, AID_RADIO, AID_RADIO, 0 },
{ "/dev/diag_arm9", 0660, AID_RADIO, AID_RADIO, 0 },
{ "/dev/android_adb", 0660, AID_ADB, AID_ADB, 0 },
{ "/dev/android_adb_enable", 0660, AID_ADB, AID_ADB, 0 },
{ "/dev/ttyMSM0", 0600, AID_BLUETOOTH, AID_BLUETOOTH, 0 },
{ "/dev/ttyHS0", 0600, AID_BLUETOOTH, AID_BLUETOOTH, 0 },
{ "/dev/uinput", 0660, AID_SYSTEM, AID_BLUETOOTH, 0 },
{ "/dev/alarm", 0664, AID_SYSTEM, AID_RADIO, 0 },
{ "/dev/tty0", 0660, AID_ROOT, AID_SYSTEM, 0 },
{ "/dev/graphics/", 0660, AID_ROOT, AID_GRAPHICS, 1 },
{ "/dev/msm_hw3dm", 0660, AID_SYSTEM, AID_GRAPHICS, 0 },
{ "/dev/input/", 0660, AID_ROOT, AID_INPUT, 1 },
{ "/dev/eac", 0660, AID_ROOT, AID_AUDIO, 0 },
{ "/dev/cam", 0660, AID_ROOT, AID_CAMERA, 0 },
{ "/dev/pmem", 0660, AID_SYSTEM, AID_GRAPHICS, 0 },
{ "/dev/pmem_adsp", 0660, AID_SYSTEM, AID_AUDIO, 1 },
{ "/dev/pmem_camera", 0660, AID_SYSTEM, AID_CAMERA, 1 },
{ "/dev/oncrpc/", 0660, AID_ROOT, AID_SYSTEM, 1 },
{ "/dev/adsp/", 0660, AID_SYSTEM, AID_AUDIO, 1 },
{ "/dev/snd/", 0660, AID_SYSTEM, AID_AUDIO, 1 },
{ "/dev/mt9t013", 0660, AID_SYSTEM, AID_SYSTEM, 0 },
{ "/dev/msm_camera/", 0660, AID_SYSTEM, AID_SYSTEM, 1 },
{ "/dev/akm8976_daemon",0640, AID_COMPASS, AID_SYSTEM, 0 },
{ "/dev/akm8976_aot", 0640, AID_COMPASS, AID_SYSTEM, 0 },
{ "/dev/akm8973_daemon",0640, AID_COMPASS, AID_SYSTEM, 0 },
{ "/dev/akm8973_aot", 0640, AID_COMPASS, AID_SYSTEM, 0 },
{ "/dev/bma150", 0640, AID_COMPASS, AID_SYSTEM, 0 },
{ "/dev/cm3602", 0640, AID_COMPASS, AID_SYSTEM, 0 },
{ "/dev/akm8976_pffd", 0640, AID_COMPASS, AID_SYSTEM, 0 },
{ "/dev/lightsensor", 0640, AID_SYSTEM, AID_SYSTEM, 0 },
{ "/dev/msm_pcm_out", 0660, AID_SYSTEM, AID_AUDIO, 1 },
{ "/dev/msm_pcm_in", 0660, AID_SYSTEM, AID_AUDIO, 1 },
{ "/dev/msm_pcm_ctl", 0660, AID_SYSTEM, AID_AUDIO, 1 },
{ "/dev/msm_snd", 0660, AID_SYSTEM, AID_AUDIO, 1 },
{ "/dev/msm_mp3", 0660, AID_SYSTEM, AID_AUDIO, 1 },
{ "/dev/audience_a1026", 0660, AID_SYSTEM, AID_AUDIO, 1 },
{ "/dev/tpa2018d1", 0660, AID_SYSTEM, AID_AUDIO, 1 },
{ "/dev/msm_audpre", 0660, AID_SYSTEM, AID_AUDIO, 0 },
{ "/dev/msm_audio_ctl", 0660, AID_SYSTEM, AID_AUDIO, 0 },
{ "/dev/htc-acoustic", 0660, AID_SYSTEM, AID_AUDIO, 0 },
{ "/dev/vdec", 0660, AID_SYSTEM, AID_AUDIO, 0 },
{ "/dev/q6venc", 0660, AID_SYSTEM, AID_AUDIO, 0 },
{ "/dev/snd/dsp", 0660, AID_SYSTEM, AID_AUDIO, 0 },
{ "/dev/snd/dsp1", 0660, AID_SYSTEM, AID_AUDIO, 0 },
{ "/dev/snd/mixer", 0660, AID_SYSTEM, AID_AUDIO, 0 },
{ "/dev/smd0", 0640, AID_RADIO, AID_RADIO, 0 },
{ "/dev/qemu_trace", 0666, AID_SYSTEM, AID_SYSTEM, 0 },
{ "/dev/qmi", 0640, AID_RADIO, AID_RADIO, 0 },
{ "/dev/qmi0", 0640, AID_RADIO, AID_RADIO, 0 },
{ "/dev/qmi1", 0640, AID_RADIO, AID_RADIO, 0 },
{ "/dev/qmi2", 0640, AID_RADIO, AID_RADIO, 0 },
/* CDMA radio interface MUX */
{ "/dev/ts0710mux", 0640, AID_RADIO, AID_RADIO, 1 },
{ "/dev/ppp", 0660, AID_RADIO, AID_VPN, 0 },
{ "/dev/tun", 0640, AID_VPN, AID_VPN, 0 },
{ NULL, 0, 0, 0, 0 },
};
Ⅳ android jni對底層的設備節點open問題
手敲命令可以的話，
手機和列印機應該都沒有問題。
看看你的程序消息發到下面去了沒有。
只有一步一步的跟了。
Ⅵ android 是如何找到觸摸屏設備節點
Event輸入設備驅動 Event驅動是通用的輸入設備驅動,目前可支持滑鼠,鍵盤,觸摸屏等多種輸入設備; Event設備在文件系統中的設備節點為:/dev/input/eventX,由init進程............
參考這片文章網頁鏈接
其實樓主問的這些節點不管是觸摸、輸入、音視頻交互都是由Linux系統驅動和硬體交互為上層框架提供的事件方法、要完全弄明白這些太深奧了。真相搞明白那就去搞單片機、寫驅動