Android 模拟器的上使用GPS的bug
由于最近研究Android 模拟器的GPS模块的实现,发现了模拟器GPS的bug。
启动模拟器,通过DDMS发送经纬度,通过应用可以抓到数据,进入设置,安全与位置,关闭GPS,再打开,再次打开GPS测试软件,再次发送经纬度,怎么也收不到。
查看了代码发现Android模拟器中完成GPS模块的功能主要是一个HAL层代码,通过socket接收发送过来的经纬度信息,其中代码是有问题的,GPS模块的工作主要是一个线程,当关闭GPS模块的时候这个线程结束了,再次打开的时候不会去启动这个线程,所以GPS模块就不工作了,具体看如下代码:
[cpp]
static void
gps_state_thread( void* arg )
{
GpsState* state = (GpsState*) arg;
NmeaReader reader[1];
int epoll_fd = epoll_create(2);
int started = 0;
int gps_fd = state->fd;
int control_fd = state->control[1];
nmea_reader_init( reader );
// register control file descriptors for polling
epoll_register( epoll_fd, control_fd );
epoll_register( epoll_fd, gps_fd );
D("gps thread running");
// now loop
for (;;) {
struct epoll_event events[2];
int ne, nevents;
nevents = epoll_wait( epoll_fd, events, 2, -1 );
if (nevents < 0) {
if (errno != EINTR)
LOGE("epoll_wait() unexpected error: %s", strerror(errno));
continue;
}
D("gps thread received %d events", nevents);
for (ne = 0; ne < nevents; ne++) {
if ((events[ne].events & (EPOLLERR|EPOLLHUP)) != 0) {
LOGE("EPOLLERR or EPOLLHUP after epoll_wait() !?");
return;
}
if ((events[ne].events & EPOLLIN) != 0) {
int fd = events[ne].data.fd;
if (fd == control_fd)
{
char cmd = 255;
int ret;
D("gps control fd event");
do {
ret = read( fd, &cmd, 1 );
} while (ret < 0 && errno == EINTR);
if (cmd == CMD_QUIT) {
D("gps thread quitting on demand");
return;
}
else if (cmd == CMD_START) {
if (!started) {
D("gps thread starting location_cb=%p", state->callbacks.location_cb);
started = 1;
nmea_reader_set_callback( reader, state->callbacks.location_cb );
}
}
else if (cmd == CMD_STOP) {
if (started) {
D("gps thread stopping");
started = 0;
nmea_reader_set_callback( reader, NULL );
}
}
 
补充:移动开发 , Android ,