Two ways to implement the countdown to "go" iOS development

Original: http://blog.csdn.net/kylinbl/article/details/8972261

Method 1: Use Nstimer to implement

The main use of the Nstimer Scheduledtimerwithtimeinterval method to perform a timefiremethod function every 1 seconds, timefiremethod the countdown of some operations, When finished, the timer is invalidate off, the code is as follows:

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1. Secondscountdown = 60; //60 Seconds Countdown
2. Countdowntimer = [Nstimer scheduledtimerwithtimeinterval:1 target:self selector: @selector (timefiremethod) UserInfo: Nil Repeats:yes];
3. -(void) timefiremethod{
4. secondscountdown--;
5. if (secondscountdown==0) {
6. [Countdowntimer invalidate];
7. }
8. }

Method 2: Use GCD to implement

The code is as follows:

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2. __block int timeout=300; //Countdown time
4. dispatch_queue_t queue = Dispatch_get_global_queue (Dispatch_queue_priority_default, 0);
6. dispatch_source_t _timer = dispatch_source_create (dispatch_source_type_timer, 0, 0,queue);
8. Dispatch_source_set_timer (_timer,dispatch_walltime (NULL, 0), 1.0*nsec_per_sec, 0); //per second execution
10. Dispatch_source_set_event_handler (_timer, ^{
12. if (timeout<=0) { //countdown end, close
14. Dispatch_source_cancel (_timer);
16. Dispatch_release (_timer);
18. Dispatch_async (Dispatch_get_main_queue (), ^{
20. Set the interface button to display the settings according to your needs
22. 。。。。。。。。
24. });
26. }else{
28. int minutes = TIMEOUT/60;
30. int seconds = timeout% 60;
32. NSString *strtime = [NSString stringwithformat:@"%d minutes%.2d seconds after re-obtaining the verification code", minutes, seconds];
34. Dispatch_async (Dispatch_get_main_queue (), ^{
36. //Set the interface button to display according to your own needs settings
38. 。。。。。。。。
40. });
42. timeout--;
46. }
48. });
50. Dispatch_resume (_timer);

Two ways to implement the countdown to "go" iOS development