1.HUD的选择性显示,当前控制器的View可见时,显示HUD,反之不显示。
if (self.view.window && self.isViewLoaded) { [SVProgressHUD show]; }
2.GCD实现定时器
NSTimeInterval period = 1.0; //设置时间间隔
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), period * NSEC_PER_SEC, 0); //每秒执行
__block NSInteger i = 60;
dispatch_source_set_event_handler(_timer, ^{
//在这里执行事件
dispatch_sync(dispatch_get_main_queue(), ^{
});
i--;
if (i == 0) {
dispatch_cancel(_timer);
};
});
dispatch_resume(_timer);
3.解决按钮标题闪耀问题
设置按钮为custom