今天发现动态改变button title时会出现闪动.很蛋疼的问题,后来经过反复尝试,发现一个解决方案.
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
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);
dispatch_source_set_event_handler(timer, ^{
NSInteger scondes = timeout % 60;
dispatch_async(dispatch_get_main_queue(), ^{
[_timerBtn setBackgroundColor:[UIColor blueColor]];
_timerBtn.titleLabel.text = [NSString stringWithFormat:@"%ld秒",scondes];
[_timerBtn setTitle:[NSString stringWithFormat:@"%ld秒",scondes] forState:UIControlStateNormal];
});
timeout --;
});
dispatch_resume(timer);
注意这个方法里
_timerBtn.titleLabel.text = [NSString stringWithFormat:@"%ld秒",scondes];
[_timerBtn setTitle:[NSString stringWithFormat:@"%ld秒",scondes] forState:UIControlStateNormal];
如果单独设置_timerBtn.titleLabel.text = [NSString stringWithFormat:@"%ld秒",scondes];赋值,label是不显示文字的.如果只设置[_timerBtn setTitle:[NSString stringWithFormat:@"%ld秒",scondes] forState:UIControlStateNormal];这个的话,就会出现闪动的效果..后来经过尝试,发现必须两个都存在,而且_timerBtn.titleLabel.text = [NSString stringWithFormat:@"%ld秒",scondes];这个要放在[_timerBtn setTitle:[NSString stringWithFormat:@"%ld秒",scondes] forState:UIControlStateNormal];前边,至于为什么这么做我也没找到合适的解释...
还有个方法就是用xib的时候button不用system改为custom，同理，代码用custom也不会闪