Ios ui multithreading NSThread download and display images to UIImageView

@ Property (weak, nonatomic) IBOutletUILabel * downLabelInfo;

@ Property (weak, nonatomic) IBOutletUIImageView * imageView;

@ End

@ ImplementationViewController

-(Void) viewDidLoad

{

[Super viewDidLoad];

NSString * url = @ "http://d.hiphotos.baidu.com/image/w%3D1366%3Bcrop%3D0%2C0%2C1366%2C768/sign=6cbcab9dabec8a13141a53e3c135aaec/aa64034f78f0f7369453c3730855b319ebc41316.jpg ";

@ Autoreleasepool {

NSThread * thread = [[NSThreadalloc] initWithTarget: selfselector: @ selector (downloadImage :) object: url];

[Thread start];

}

}

-(Void) didReceiveMemoryWarning

{

[Super didReceiveMemoryWarning];

}

-(Void) downloadImage :( NSString *) url {

// Put the displayed content in front of the synchronization method.

Self-> _ downLabelInfo. text = @ "downloading image ...";

// The synchronization method will be stuck in the thread until the completion position

NSData * imageData = [NSDatadataWithContentsOfURL: [NSURLURLWithString: url];

UIImage * image = [UIImageimageWithData: imageData];

If (image = nil)

{

}

Else

{

// Self-> _ downLabelInfo. text = @ "downloading image..."; so it is useless to write this statement.

[Self defined mselecw.mainthread: @ selector (updateImageView :) withObject :( image) waitUntilDone: YES];

}

}

-(Void) updateImageView :( UIImage *) image

{

Self-> _ imageView. image = image;

Self-> _ imageView. frame = CGRectMake (self. view. frame. size. width/2-100, self. view. frame. size. height/2-100,200,200 );

Self-> _ downLabelInfo. textColor = [UIColorredColor];

Self-> _ downLabelInfo. text = @ "image download completed ";

}

@ End

The second method is to use NSURLConnection sendSynchronousRequest to obtain and display the image content asynchronously.

Modify the downloadImage method as follows:

-(Void) downloadImage :( NSString *) url

{

Self-> _ downLabelInfo. text = @ "downloading image ...";

NSURLRequest * request = [NSURLRequestrequestWithURL: [NSURLURLWithString: url];

NSError * error;

NSData * data = [NSURLConnectionsendSynchronousRequest: requestreturningResponse: nilerror: & error];

If (data = nil)

{

NSLog (@ "nil ");

}

Else

{

UIImage * image = [UIImageimageWithData: data];

Self-> _ imageView. image = image;

Self-> _ downLabelInfo. textColor = [UIColorredColor];

Self-> _ downLabelInfo. text = @ "image download completed ";

}

}