IOS GCD定时器

//
//  ViewController.m
//  CX GCD 定时器
//
//  Created by ma c on 16/3/30.
//  Copyright © 2016年 xubaoaichiyu. All rights reserved.
//

#import "ViewController.h"

NSInteger count = 0;

@interface ViewController ()

//注意＊＊这里不需要??号 可以理解为dispatch_time_t 已经包含了
@property (nonatomic, strong)dispatch_source_t time;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
}

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    
    NSLog(@"欢迎来到旭宝爱吃鱼的博客");
    //获得队列
    dispatch_queue_t queue = dispatch_get_global_queue(0, 0);
    //创建一个定时器
    self.time = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue);
    //设置开始时间
    dispatch_time_t start = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3.0 * NSEC_PER_SEC));
    //设置时间间隔
    uint64_t interval = (uint64_t)(2.0* NSEC_PER_SEC);
    //设置定时器
    dispatch_source_set_timer(self.time, start, interval, 0);
    //设置回调
    dispatch_source_set_event_handler(self.time, ^{
       
        NSLog(@"旭宝爱吃鱼");
        //设置当执行五次是取消定时器
        count++;
        if(count == 5){
            
            dispatch_cancel(self.time);
            
        }
    });
    //由于定时器默认是暂停的所以我们启动一下
    //启动定时器
    dispatch_resume(self.time);
    
}
@end