iOS NSOperation的线程间通信

//1.开子线程下载图片

//1.1非主队列

NSOperationQueue*queue = [[NSOperationQueuealloc]init];

//1.2封装操作

NSBlockOperation*download = [NSBlockOperationblockOperationWithBlock:^{

NSURL*url = [NSURLURLWithString:@"http://s15.sinaimg.cn/bmiddle/4c0b78455061c1b7f1d0e"];

NSData*imageData = [NSDatadataWithContentsOfURL:url];

UIImage*image = [UIImageimageWithData:imageData];

NSLog(@"download---%@",[NSThreadcurrentThread]);

//3.更新UI

[[NSOperationQueuemainQueue]addOperationWithBlock:^{

self.imageView.image= image;

NSLog(@"UI---%@",[NSThreadcurrentThread]);

}];

}];

//2.添加操作到队列

[queueaddOperation:download];

-(void)comBie

{

//1.创建队列

NSOperationQueue*queue = [[NSOperationQueuealloc]init];

__blockUIImage*image1;

__blockUIImage*image2;

//2封装操作,下载图片1

NSBlockOperation*download1 = [NSBlockOperationblockOperationWithBlock:^{

NSURL*url = [NSURLURLWithString:@"http://s15.sinaimg.cn/bmiddle/4c0b78455061c1b7f1d0e"];

NSData*imageData = [NSDatadataWithContentsOfURL:url];

image1 = [UIImageimageWithData:imageData];

NSLog(@"download---%@",[NSThreadcurrentThread]);

}];

//3封装操作,下载图片2

NSBlockOperation*download2 = [NSBlockOperationblockOperationWithBlock:^{

NSURL*url = [NSURLURLWithString:@"http://www.027art.com/feizhuliu/UploadFiles_6650/201109/2011091718442835.jpg"];

NSData*imageData = [NSDatadataWithContentsOfURL:url];

image2 = [UIImageimageWithData:imageData];

NSLog(@"download---%@",[NSThreadcurrentThread]);

}];

//4.封装合并图片的操作

NSBlockOperation*combie = [NSBlockOperationblockOperationWithBlock:^{

//4.1开上下文

UIGraphicsBeginImageContext(CGSizeMake(200,200));

//4.2画图1

[image1drawInRect:CGRectMake(0,0,100,200)];

//4.3画图2

[image2drawInRect:CGRectMake(100,0,100,200)];

//4.4根据上下文得到图片

UIImage*image =UIGraphicsGetImageFromCurrentImageContext();

//4.5关闭上下文

UIGraphicsEndImageContext();

//7.更新UI

[[NSOperationQueuemainQueue]addOperationWithBlock:^{

self.imageView.image= image;

NSLog(@"UI----%@",[NSThreadcurrentThread]);

}];

}];

//5.设置依赖关系

[combieaddDependency:download1];

[combieaddDependency:download2];

//6.添加操作到队列中

[queueaddOperation:download2];

[queueaddOperation:download1];

[queueaddOperation:combie];

}