1 // 2 // ViewController.m 3 // 05-GCD延迟调用 4 // 5 // Created by mac on 16/4/21. 6 // Copyright © 2016年 mac. All rights reserved. 7 // 8 9 #import "ViewController.h" 10 11 @interface ViewController () 12 13 @end 14 15 @implementation ViewController 16 17 - (void)viewDidLoad { 18 [super viewDidLoad]; 19 20 } 21 22 - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event { 23 24 [self delay3]; 25 } 26 27 /** 28 * 非延迟调用 29 */ 30 - (void)delayThread1 { 31 32 dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0); 33 dispatch_after(DISPATCH_TIME_NOW, queue, ^{ 34 35 NSLog(@"delay === %@", [NSThread currentThread]); 36 }); 37 } 38 /** 39 * 延迟调用，且开启多线程 40 */ 41 - (void)delayThread2 { 42 43 dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0); 44 dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3 * NSEC_PER_SEC)), queue, ^{ 45 46 NSLog(@"delayThread2===%@", [NSThread currentThread]); 47 }); 48 } 49 50 /** 51 * 一下三个方法实现了延迟调用，未开启多线程，在主线程中执行 52 */ 53 - (void)delay1 { 54 55 [NSThread sleepForTimeInterval:3]; 56 NSLog(@"delay1=%@", [NSThread currentThread]); 57 } 58 - (void)delay2 { 59 60 [self performSelector:@selector(download:) withObject:@"http://333.jpg" afterDelay:3]; 61 } 62 - (void)delay3 { 63 64 dispatch_queue_t queue = dispatch_get_main_queue(); 65 dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3 * NSEC_PER_SEC)), queue, ^{ 66 67 NSLog(@"delay3=%@", [NSThread currentThread]); 68 69 }); 70 71 /*GCD :与上面的等价 72 dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{ 73 74 NSLog(@"delay3=%@", [NSThread currentThread]); 75 76 });*/ 77 78 79 80 NSLog(@"delay====%@", [NSThread currentThread]); 81 } 82 83 - (void)download:(NSString *)url { 84 85 NSLog(@"delay2=%@", [NSThread currentThread]); 86 } 87 88 89 @end