CADisplayLink简单实用

#import "ViewController.h"

@interface ViewController ()
{
    CADisplayLink *displayLink;
    NSInteger time;
}

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(updateDisplay:)];
    [displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];//添加到循环并启动
    displayLink.frameInterval = 60;//设置帧率为每秒一次(默认为每秒60次)
    //控制计时器暂停与恢复的属性。设置为YES的时候会暂停事件的触发
    displayLink.paused = YES;
    
    time = 60;//设置时间
}

//刷新时调用
- (void)updateDisplay:(CADisplayLink *)cadisplaylink{
    time -= 1;
    if (time == 0) {
        [displayLink invalidate];
    }
    NSLog(@"time:%ld", (long)time);
}