//ButtonCountDown.h
    +(void)countDownButton:(UIButton *)sender withTitle:(NSString *)title withBackgroundColor:(UIColor* )color withCountDownTime:(NSInteger)timeNum;

    //ButtonCountDown.m
    +(void)countDownButton:(UIButton *)sender withTitle:(NSString *)title withBackgroundColor:(UIColor* )color withCountDownTime:(NSInteger)timeNum{
__block NSInteger time = timeNum; //倒計時時間

//    [sender setTitle:@"重新發(fā)送" forState:UIControlStateNormal];
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
//設(shè)置按鈕的樣式
dispatch_source_set_event_handler(_timer, ^{
    if(time <= 0){ //倒計時結(jié)束，關(guān)閉
        dispatch_source_cancel(_timer);
        dispatch_async(dispatch_get_main_queue(), ^{
            [sender setTitleColor:color forState:UIControlStateNormal];
            [sender setTitle:title forState:UIControlStateNormal];
            sender.userInteractionEnabled = YES;
        });
    }else{
        int seconds = time % 60;
        dispatch_async(dispatch_get_main_queue(), ^{
            //設(shè)置按鈕顯示讀秒效果
            [sender setTitle:[NSString stringWithFormat:@"%.2dS", seconds] forState:UIControlStateNormal];
            [sender setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
            sender.userInteractionEnabled = NO;
        });
        time--;
    }
});
dispatch_resume(_timer);
}