iOS clock animation

 　　In iOS development, the timer is not able to accurately NSTimer departure, usually NSTimer can only control the operation does not require precise handling, while CADisplayLink that every time the screen refreshes, the notification system. The greatest advantage is that you can CADisplayLink accurate at each screen refresh, set to redraw the screen!

　　Sample code:

　　

 1 #import "WKViewController.h"
 2 
 3 @interface WKViewController ()
 4 
 5 @end
 6 /**
 7  
 8  */
 9 @implementation WKViewController
10 {
11     CADisplayLink *_timer;
12 }
13 
14 - (void)viewDidLoad
15 {
16     [super viewDidLoad];
17     
18     _timer = [CADisplayLink displayLinkWithTarget:self selector:@selector(snow)];
19     // the clock cycle added to the main run, it is possible to work at each screen refresh
 20     // 60 times per second 
21 is      [_timer addToRunLoop: [the NSRunLoop mainRunLoop] forMode: NSDefaultRunLoopMode];
 22 is  }
 23 is  
24  
25 - ( void ) Snow
 26  {
 27      // much time for controlling the operation of a 
28      static  Long counter = 0 ;
 29      
30      counter ++ ;
 31 is      
32      IF (% counter ( 15 ) == 0 ) {
 33 is            // do something 
34 is      }
 35     
36 }
37 
38 
39 @end

 

Reproduced in: https: //www.cnblogs.com/pretty-guy/p/4067495.html