ViewController.m#

//
//  ViewController.m
//  多线程_GCD2

#import "ViewController.h"
#import "UIImageView+WebCatc.h"
@interface ViewController ()

@property(nonatomic, strong)UIImageView *imageV;

@property(nonatomic, strong)UIScrollView *scrollV;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
 //  // //
    _imageV = [[UIImageView alloc] initWithFrame:CGRectMake(0, 200, 414, 500)];
    [self.view addSubview:_imageV];

 // // //
    
   
    
    
    
    
}


- (IBAction)downLoadImageAction:(UIButton *)sender {
    
    NSLog(@"加载图片");
    
    NSString *str = @"http://v1.qzone.cc/pic/201512/26/15/07/567e3ca50c589469.jpg!600x600.jpg";
    
    [_imageV setImageWithURL:[NSURL URLWithString:str]];
    

    
}


- (IBAction)load:(id)sender {
    
    NSLog(@"加载轮播图");
     self.scrollV = [[UIScrollView alloc] initWithFrame:CGRectMake (0,100,414,500)];
    
    _scrollV.contentSize = CGSizeMake(414*5,500);
    for (int i = 0; i <5; i++) {
        UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(414*i, 0, 414, 500)];
        
        NSString *urlString = @"http://v1.qzone.cc/pic/201512/26/15/07/567e3ca50c589469.jpg!600x600.jpg";
        [imageView setImageWithURL:[NSURL URLWithString:urlString]];
        [self.scrollV addSubview:imageView];
    }
    
    
    
    
    [self.view addSubview:self.scrollV];
    


}

- (IBAction)lianxutupian:(UIButton *)sender {
    
    NSLog(@"加载连续图片");
    
    // // // //
    for (int i = 0; i < 10; i++) {


        UIImageView *imageV = [[UIImageView alloc] initWithFrame:CGRectMake(0, 200*i+50, 394, 200)];

        [self.view addSubview:imageV];

        NSString *urlString = @"http://v1.qzone.cc/pic/201512/26/15/07/567e3ca50c589469.jpg!600x600.jpg";

        [imageV setImageWithURL:[NSURL URLWithString:urlString]];

    }

    
    
    
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

UIImageView+WebCatc.h#

//
//  UIImageView+WebCatch.h
// 多线程_GCD2

//

#import <UIKit/UIKit.h>

@interface UIImageView (WebCatch)

-(void)setImageWithURL:(NSURL *)url;

@end

UIImageView+WebCatc.m#

//
//  UIImageView+WebCatch.m
//  多线程_GCD2
//


#import "UIImageView+WebCatc.h"

@implementation UIImageView (WebCatch)

//法一
-(void)setImageWithURL:(NSURL *)url{

    dispatch_queue_t queue = dispatch_queue_create("loadImage", NULL);
    dispatch_async(queue, ^{
        
        NSData *data = [NSData dataWithContentsOfURL:url];
        
        UIImage *image = [UIImage imageWithData:data];
        
        
        dispatch_sync(dispatch_get_main_queue(), ^{
            self.image = image;
        });
    });
    
    

    
}

//法二
//-(void)setImageWithURL:(NSURL *)url{
//
//   [self performSelectorOnMainThread:@selector(loadData:) withObject:url waitUntilDone:YES];
//
//}
//
//
//-(void)loadData:(NSURL *)url{
//    
//    @autoreleasepool {
//        
//        NSData *data = [NSData dataWithContentsOfURL:url];
//        
//        UIImage *image = [UIImage imageWithData:data];
//        
//        //在主线程上执行setImage方法
//        
//        [self performSelectorOnMainThread:@selector(setImages:) withObject:image waitUntilDone:YES];
//        
//    }
//    
//}

@end