短信倒計時

__block int timeout= 59; //倒計時時間 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); //每秒執行 dispatch_source_set_event_handler(_timer, ^{ if(timeout<=0){ //倒計時結束，關閉 dispatch_source_cancel(_timer); dispatch_async(dispatch_get_main_queue(), ^{ //設置界面的按鈕顯示 根據本身需求設置 [_codeButton setTitle:@"獲取驗證碼" forState:UIControlStateNormal]; _codeButton.userInteractionEnabled = YES; }); }else{ // int minutes = timeout / 60; int seconds = timeout % 60; NSString *strTime = [NSString stringWithFormat:@"%.2d", seconds]; dispatch_async(dispatch_get_main_queue(), ^{ //設置界面的按鈕顯示 根據本身需求設置 [UIView beginAnimations:nil context:nil]; [UIView setAnimationDuration:1]; [_codeButton setTitle:[NSString stringWithFormat:@"%@秒重發",strTime] forState:UIControlStateNormal]; [UIView commitAnimations]; _codeButton.userInteractionEnabled = NO; }); timeout--; } }); dispatch_resume(_timer);

}