Code for communication between threads

#import "ViewController.h"

@interface viewcontroller ()

picture frame Uiimageview

@property (weak, nonatomic) iboutlet uiimageview *imageview;

@end

@implementation Viewcontroller

-(void) viewdidload {

[Super viewdidload];

additional setup after loading the view, typically from a nib.

}

Create a sub-thread to perform the download of this time-consuming action click Method

-(void) Touchesbegan: (nsset *) touches withevent: (uievent *) event

{

the picture to download

nsstring *urlstring = @ "http://p1.yokacdn.com/pic/star/topic/2011/ U288p1t117d414828f2577dt20110902111814.jpg ";

//1. in sub-threading slices

nsthread *thread = [[nsthread alloc] initwithtarget:self selector :@selector(downloadwebimage:) object: urlstring];

put it in the callable thread pool .

[Thread start];

}

Download the web image Download method

-(void) Downloadwebimage: (nsstring *) urlstring

{

NSLog(@ "downloadwebimagebegan:%@", [nsthread currentthread]);

// Uniform Resource Locator 1> the address of the image to be downloaded to the Uniform Resource Locator

nsurl *url = [nsurl urlwithstring: urlstring];

// download image data Contents content download 2> convert a Uniform Resource Locator to data /c11>

nsdata *data = [nsdata datawithcontentsofurl: url];

// convert picture 3> data to Image

UIImage *image = [UIImage imagewithdata:d ATA];

//2. display pictures on the main thread

//[Self Performselectoronmainthread: @selector (setupimage:) withobject:image Waituntildone:yes];

when a picture is downloaded from a child thread , It is displayed in the main thread

[self performselector:@selector(setupimage:) onthread: [nsthread mainthread] withobject: Image Waituntildone: NO];

Print Current thread

NSLog(@ "downloadwebimageend:%@", [nsthread currentthread]);

}

set up a picture

-(void) Setupimage: (UIImage *) image

{

NSLog(@ "setupimage:%@", [nsthread currentthread]);

// show Pictures

self. ImageView. Image = image;

}

@end

Code for communication between threads