//BlockOperation //
// ViewController.swift import UIKit class ViewController: UIViewController { @IBOutlet weak var image1: UIImageView!
@IBOutlet weak var image2: UIImageView!
@IBOutlet weak var image3: UIImageView!
@IBOutlet weak var image4: UIImageView! let imageUrls = [
"https://dn-boxueio.qbox.me/image1-big.jpg",
"https://dn-boxueio.qbox.me/image2-big.jpg",
"https://dn-boxueio.qbox.me/image3-big.jpg",
"https://dn-boxueio.qbox.me/image4-big.jpg"
] override func viewDidLoad() {
super.viewDidLoad()
// present(<#T##viewControllerToPresent: UIViewController##UIViewController#>, animated: <#T##Bool#>, completion: nil)
// Do any additional setup after loading the view, typically from a nib.
} override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
} @IBAction func clearDownload(_ sender: UIButton) { // self.image1.image=UIImage(named: <#T##String#>) self.image1.image = nil
self.image2.image = nil
self.image3.image = nil
self.image4.image = nil URLCache.shared.removeAllCachedResponses()
} let queue = OperationQueue() @IBAction func cancelDownload(_ sender: AnyObject) {
self.queue.cancelAllOperations()
} @IBAction func downloadImages(_ sender: UIButton) { // queue.addOperation({
//
//
// let img1 = Downloader.downloadImageWithURL(self.imageUrls[0])
//
// OperationQueue.main.addOperation({
// self.image1.image = img1
// self.image1.clipsToBounds = true
// })
// })
//
//
let op1 = BlockOperation(block: {
let img1 = Downloader.downloadImageWithURL(self.imageUrls[0]) OperationQueue.main.addOperation({
self.image1.image = img1
self.image1.clipsToBounds = true
})
})
op1.completionBlock = { print("image1 downloaded") } let op2 = BlockOperation(block: {
let img2 = Downloader.downloadImageWithURL(self.imageUrls[1]) OperationQueue.main.addOperation({
self.image2.image = img2
self.image2.clipsToBounds = true
})
})
op2.completionBlock = { print("image2 downloaded") } let op3 = BlockOperation(block: {
let img3 = Downloader.downloadImageWithURL(self.imageUrls[2]) OperationQueue.main.addOperation({
self.image3.image = img3
self.image3.clipsToBounds = true
})
})
op3.completionBlock = { print("image3 downloaded") } let op4 = BlockOperation(block: {
let img4 = Downloader.downloadImageWithURL(self.imageUrls[3]) OperationQueue.main.addOperation({
self.image4.image = img4
self.image4.clipsToBounds = true
})
})
op4.completionBlock = { print("image4 downloaded") } // op3.addDependency(op4)
// op2.addDependency(op3) queue.addOperation (op1)
queue.addOperation(op4)
queue.addOperation(op3)
queue.addOperation(op2)
}
} //GCD实用代码块 import UIKit class ViewController: UIViewController { @IBOutlet weak var image1: UIImageView!
@IBOutlet weak var image2: UIImageView!
@IBOutlet weak var image3: UIImageView!
@IBOutlet weak var image4: UIImageView! let imageUrls = [
"https://dn-boxueio.qbox.me/image1-big.jpg",
"https://dn-boxueio.qbox.me/image2-big.jpg",
"https://dn-boxueio.qbox.me/image3-big.jpg",
"https://dn-boxueio.qbox.me/image4-big.jpg"
] override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
} override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
} @IBAction func clearDownload(_ sender: UIButton) {
self.image1.image = nil
self.image2.image = nil
self.image3.image = nil
self.image4.image = nil URLCache.shared.removeAllCachedResponses()
} func loadImageWithURL(_ url:String) -> UIImage! {
let data = try? Data(contentsOf: URL(string: url)!)
return UIImage(data: data!) } @IBAction func downloadImages(_ sender: UIButton) { var currQueue = DispatchQueue.global(qos: .default)
// currQueue = DispatchQueue(label: "com.boxueio.images", attributes: .concurrent)
//并行
currQueue=DispatchQueue(label: "currqueue1", qos: .default, attributes: .concurrent) // dispatch_async
currQueue.async(execute: {
let img1 = self.loadImageWithURL(self.imageUrls[0])
DispatchQueue.main.async(execute: {
self.image1.image = img1
self.image1.clipsToBounds = true
})
}) currQueue.async(execute: {
let img2 = self.loadImageWithURL(self.imageUrls[1])
DispatchQueue.main.async(execute: {
self.image2.image = img2
self.image2.clipsToBounds = true
})
}) currQueue.async(execute: {
let img3 = Downloader.downloadImageWithURL(self.imageUrls[2])
DispatchQueue.main.async(execute: {
self.image3.image = img3
self.image3.clipsToBounds = true
})
}) currQueue.async(execute: {
let img4 = Downloader.downloadImageWithURL(self.imageUrls[3])
DispatchQueue.main.async(execute: {
self.image4.image = img4
self.image4.clipsToBounds = true
})
})
}
} //class图片基类 import UIKit
class Downloader { class func downloadImageWithURL(_ url:String) -> UIImage! {
let data = try? Data(contentsOf: URL(string: url)!)
return UIImage(data: data!)
}
}