dispatch_queue_t?queue?=?dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,?0);
dispatch_source_t?timer?=?dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER,?0,?0,queue);
dispatch_source_set_timer(timer,dispatch_walltime(NULL, 0),1.0*NSEC_PER_SEC, 0); //每秒執(zhí)行
dispatch_source_set_event_handler(timer, ^{
//@"倒計時結(jié)束拉队，關(guān)閉"
dispatch_source_cancel(timer);
dispatch_async(dispatch_get_main_queue(), ^{
if (second >= 0) {?
[_getNumBtn setTitle:[NSString stringWithFormat:@"(%ld)重發(fā)驗證碼",second] forState:UIControlStateNormal]; second—;?
}?else {
//這句話必須寫否則會出問題 dispatch_source_cancel(timer); [_getNumBtn setTitle:@"獲取驗證碼" forState:UIControlStateNormal];?
}
});
});
dispatch_resume(timer);
