IOS加载网络图片的框架（共有4中方法）

框架名为：UIImage+WebCache.h 继承于UIimageView

框架里面加载网络图片的方法共4中：分别为1.普通加载 2.线程NSThread 3.

#import "ViewController.h"

#import "UIImage+WebCache.h"

@interface
ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

[super
viewDidLoad];

imageArray = [NSMutableArray
array];

for(int i =
0;i < 5;i++){

for(int j =
0;j < 6;j++){

UIImageView *imageView = [[UIImageView
alloc] initWithFrame:CGRectMake(j*65 +5, i*64 +10,
60, 60)];
imageView.backgroundColor = [UIColor
cyanColor];
[self.view
addSubview:imageView];

[imageArray
addObject:imageView];
}

}

UIButton *button = [UIButton
buttonWithType:UIButtonTypeRoundedRect];
button.frame =
CGRectMake(160,
400, 80,
30);

[button setTitle:@"载入"
forState:UIControlStateNormal];

[button addTarget:self
action:@selector(buttonAction)
forControlEvents:UIControlEventTouchUpInside];

[self.view
addSubview:button];

}
- (void)buttonAction{

for(UIImageView *imageView
in imageArray){

NSString *string =
@"http://img3.douban.com/view/photo/photo/public/p2221339563.jpg";

NSURL *url = [NSURL
URLWithString:string];

[imageView
setImageWithURL:url];
}
}

UIImage+WebCache.h 自定义一个方法

#import <UIKit/UIKit.h>

@interface UIImageView (WebCache)

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

@end

UIImage+WebCache.m-------- 方法的实现

#import "UIImage+WebCache.h"

@implementation UIImageView (WebCache)

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

//第一种方法：普通的加载

/*

NSData *data = [NSData dataWithContentsOfURL:url];

UIImage *image = [UIImage imageWithData:data];

[self setImage:image];

*/

//第二种方法：线程

//NSThread *thread = [[NSThread alloc] initWithTarget:self selector:@selector(loadImage:) object:url];

//[thread start];

//第三种方法：队列

/* NSOperationQueue *queue = [[NSOperationQueue alloc] init];

//操作数

NSBlockOperation *op = [NSBlockOperation blockOperationWithBlock:^{

NSData *data = [NSData dataWithContentsOfURL:url];

UIImage *image = [UIImage imageWithData:data];

//使用主队列来回到主线程

//在主线程上修改UI

[[NSOperationQueue mainQueue] addOperationWithBlock:^{

//修改UI界面

[self setImage:image];

}];

}];

[queue addOperation:op];

*/

//----------------GCD---------------

// //1.创建Queue

// dispatch_queue_t queue = dispatch_queue_create("com.xw.gcd.queue", DISPATCH_QUEUE_CONCURRENT);//并行队列

//

// //2.创建要执行的任务，加到队列中

// dispatch_async(queue, ^{

//

// NSData *data = [NSData dataWithContentsOfURL:url];

// UIImage *image = [UIImage imageWithData:data];

// [self setImage:image];

// });

//用系统给的queue---

// (两个参数)

//参数1：优先级

//参数2：标识符

dispatch_queue_t globalQueue =
dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,
0);

dispatch_async(globalQueue, ^{

//请求数据

NSData *data = [NSData
dataWithContentsOfURL:url];

UIImage *image = [UIImage
imageWithData:data];

//显示在UI界面上

dispatch_async(dispatch_get_main_queue(), ^{

//UI相关的代码

//UI界面的刷新最好回到主线程中
[self
setImage:image];
});
});

}

- (void)loadImage:(NSURL *)url{

NSData *data = [NSData
dataWithContentsOfURL:url];

UIImage *image = [UIImage
imageWithData:data];
[self
setImage:image];

}

@end