iOS 主线程更新UI

昨天用了下线程

m_alarmCount = 0;

[_alarmTableView reloadData];

_alarmActivity.hidden = NO;

_alarmStateLabel.hidden = NO;

[_alarmActivity startAnimating];

self.alarmStateLabel.text = [NSString stringWithFormat:@"获取状态中..."];

dispatch_async(dispatch_get_global_queue(0, 0), ^{

int i = 0;

i = [m_logic getAlarmOutCount:m_StatusResult.devID count:&m_alarmCount];

i = [m_logic getAlarmOut:m_StatusResult.devID state:&m_alarmState];

dispatch_async(dispatch_get_main_queue(), ^{

if (m_alarmCount == 0) {

self.alarmStateLabel.text = [NSString stringWithFormat:@"该设备无报警输出通道"];

}

if (i != 0) {

self.alarmStateLabel.text = [NSString stringWithFormat:@"获取报警通道失败"];

}

if (i == 0 && m_alarmCount > 0) {

_alarmStateLabel.hidden = YES;

}

[_alarmActivity stopAnimating];

_alarmActivity.hidden = YES;

[_alarmTableView reloadData];

});

});

最开始把label放入全局异步中，发现无法进行UI更新，需拿出来才可，开发时需牢记：UI的更新只能写在主线程中，否则无法更新