How to asynchronously download images in ios? - ios

Question

I want to first create imageview onto the scroll view.there i set placeholder image or give Background color of imageview.so all image view are display.
- (void)LoadDataInScrollView
{
dispatch_queue_t imageQueue = dispatch_queue_create("Image Queue",NULL);
//totalImageGetDict into count total Number of object and generate imageview.
for (int ivalue = 0; ivalue < [totalImageGetDict count]; ivalue++)
{
dispatch_async(imageQueue, ^{
//define x value
CGFloat xOrigin =ivalue *ascrollView.frame.size.width+50;
imageView = [[UIImageView alloc] init];
imageView.tag = ivalue;
[imageView setBackgroundColor:[UIColor whiteColor]];
imageView.frame = CGRectMake(xOrigin-40,imgYpos, ascrollView.frame.size.width-20, scrollViewHight);
//then here first i set already downloaded image.it's comes from another class. getImageLoadDict into images are already downloaded**
if ([getImageLoadDict objectForKey:[NSNumber numberWithInteger:ivalue]]!= nil)
{
//dispatch_async(dispatch_get_main_queue(), ^{
[imageView setImage:[getImageLoadDict objectForKey:[NSNumber numberWithInteger:ivalue]]];
//});
}
else
{
//totalImageGetDict into remaining images object and asynchronously download here.
STVisionPhoto *photoObj = [totalImageGetDict objectForKey:[NSNumber numberWithInteger:ivalue]];
UIImage *newimage = [photoObj image];
dispatch_async(dispatch_get_main_queue(), ^{
[imageView setImage:newimage];
});
}
[ascrollView addSubview:imageView];
});
}
}

Answer 1

You can use SDWebImage to do it.It is pretty easy to use
Edit :
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
UIImage * image = [UIImage imageWithData:[NSData dataWithContentsOfURL:your url]];
dispatch_async(dispatch_get_main_queue(), ^{
[imgview setImage:image];
});
});
You can try this if you don't want to use any library

Answer 2

Try to use this code:
UIImageView *imgView = [[UIImageView alloc] init];
imgView.frame = CGRectMake(12.5, 12.5, 80, 80);
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
UIImage *profileImage;
profileImage = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:YOUR_URL_STRING]]];
dispatch_async(dispatch_get_main_queue(), ^{
imgView.image = profileImage;
});
});
[cell.contentView addSubview:imgView];

Answer 3

(void)loadImg:(NSString *)url img :(UIImageView *)imgView{
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:url]];
__weak UIImageView *imageV = imgView;
[imgView setImageWithURLRequest:request placeholderImage:[UIImage imageNamed:#"songRecDef"] success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) {
imageV.image = image;
[imageV setNeedsLayout];
NSLog(#"%#",response);
} failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) {
[imageV setImage:[UIImage imageNamed:#"songRecDef"]];
NSLog(#"%#",error);
}];
}