前言:前段時(shí)間汪拥，測試同事測試出一個(gè)問題。那就是手機(jī)號(hào)注冊(cè)碼發(fā)送以后抚垃，發(fā)送按鈕進(jìn)入倒計(jì)時(shí)喷楣，而后將程序退入后臺(tái)趟大，當(dāng)過了5分鐘以后鹤树。NSTimer就顯示的時(shí)間沒有改變。還有一種不和邏輯的現(xiàn)象就是：時(shí)間會(huì)亂序逊朽。一會(huì)5s 一會(huì)7s. (-_-)當(dāng)然了這個(gè)問題是我沒控制好NSTimer 的NSRunloop罕伯。 為了避免這種復(fù)雜的要注意點(diǎn),我采用了GCD里邊的信號(hào)量來做倒計(jì)時(shí)按鈕。其一：在后臺(tái)也進(jìn)程也不會(huì)中斷叽讳，會(huì)按照物理時(shí)間繼續(xù)減少秒數(shù)追他。其二：完全避免了會(huì)亂序的情況。 廢話不多說岛蚤，上代碼邑狸。
- (void)countDownBegin:(UIButton *)sender{
NSTimeInterval seconds =60;
NSDate *endTime = [NSDate dateWithTimeIntervalSinceNow:seconds];// 最后期限
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0);
dispatch_source_t _sometimer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER,0,0, queue);
dispatch_source_set_timer(_sometimer, dispatch_walltime(NULL,0),1.0*NSEC_PER_SEC,0);// 每秒執(zhí)行一次
dispatch_source_set_event_handler(_sometimer, ^{
int interval = [endTime timeIntervalSinceNow];
if(interval >0) {// 更新倒計(jì)時(shí)
NSString *timeStr = [NSString stringWithFormat:@"%ds", interval];
dispatch_async(dispatch_get_main_queue(), ^{
[sender setTitle:timeStr forState:UIControlStateNormal]; sender.userInteractionEnabled =NO;
[sender setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
});
}else{
// 倒計(jì)時(shí)結(jié)束，關(guān)閉
dispatch_source_cancel(_sometimer);
dispatch_async(dispatch_get_main_queue(), ^{
[sender setTitle:@"獲取驗(yàn)證碼"forState:UIControlStateNormal];
[sender setTitleColor:[UIColor blueColor] forState:UIControlStateNormal]; sender.userInteractionEnabled =YES;
});
}
});
dispatch_resume(_sometimer);
}
