GCD Open sub-thread download picture

Open sub-thread download picture

1. Get a global serial queue
dispatch_queue_t queue = Dispatch_get_global_queue (Dispatch_queue_priority_default, 0);
__weak typeof (self) weakself = self;

2. Add the task to the queue to execute
Dispatch_async (Queue, ^{
Nsurl *url = [Nsurl urlwithstring:_imgstring];
NSData *imagedata = [NSData Datawithcontentsofurl:url];
UIImage * Bgimage = [UIImage imagewithdata:imagedata];
Bgimage = [Bgimage applylighteffectatframe:cgrectmake (0, 0, BgImage.size.width, bgImage.size.height)];
3. Go back to the main thread
Dispatch_async (Dispatch_get_main_queue (), ^{
WeakSelf.backImageView.image = Bgimage;
});
});

GCD Open sub-thread download picture