1 #import <UIKit/UIKit.h>
2
3 @interface DemoDispatchQueueViewController : UIViewController
4 @property(nonatomic,strong) UIImageView *imageView;
5 @end

 1 #import "DemoDispatchQueueViewController.h"2 3 @interface DemoDispatchQueueViewController ()4 5 @end6 7 @implementation DemoDispatchQueueViewController8 @synthesize imageView;9 - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
10 {
11     self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
12     if (self) {
13     }
14     return self;
15 }
16
17 - (void)viewDidLoad
18 {
19     [super viewDidLoad];
20     // Do any additional setup after loading the view.
21     self.title = @"GCD Demo";
22
23     self.imageView = [[UIImageView alloc] initWithFrame:CGRectMake(10, 10, 300, 380)];
24
25     self.imageView.contentMode = UIViewContentModeScaleToFill;
26
27     [self.view addSubview:imageView];
28
29     [NSThread detachNewThreadSelector:@selector(loadImageByUrl:) toTarget:self withObject:@"http://image.rayliimg.cn/0008/2009-01-15/images/2009115135825184.jpg"];
30
31 }
32
33 -(void) loadImageByUrl:(NSString *) imageUrl
34 {
35     NSLog(@"url is :%@",imageUrl);
36     NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:imageUrl]];
37     UIImage *image = [UIImage imageWithData:data];
38
39     if(image != nil){
40         [self performSelectorOnMainThread:@selector(setImage:) withObject:image waitUntilDone:YES];
41     }else{
42         NSLog(@"无法载入相应的图片");
43     }
44 }
45 -(void) setImage:(UIImage*) image{
46     [self.imageView setImage:image];
47 }
48
49
50 - (void)didReceiveMemoryWarning
51 {
52     [super didReceiveMemoryWarning];
53     // Dispose of any resources that can be recreated.
54 }
55
56 @end