如何使用线程在迅速?
dispatchOnMainThread:^{
NSLog(@"Block Executed On %s", dispatch_queue_get_label(dispatch_get_current_queue()));
}];
如何使用线程在迅速?
dispatchOnMainThread:^{
NSLog(@"Block Executed On %s", dispatch_queue_get_label(dispatch_get_current_queue()));
}];
当前回答
dispatch_async(dispatch_get_global_queue(QOS_CLASS_BACKGROUND, 0), {
// Conversion into base64 string
self.uploadImageString = uploadPhotoDataJPEG.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.EncodingEndLineWithCarriageReturn)
})
其他回答
Swift 3.0 +
在Swift 3.0中,很多东西都被现代化了。在后台队列上运行一些东西看起来像这样:
DispatchQueue.global(qos: .userInitiated).async {
print("This is run on a background queue")
DispatchQueue.main.async {
print("This is run on the main queue, after the previous code in outer block")
}
}
Swift 1.2到2.3
let qualityOfServiceClass = QOS_CLASS_USER_INITIATED
let backgroundQueue = dispatch_get_global_queue(qualityOfServiceClass, 0)
dispatch_async(backgroundQueue, {
print("This is run on a background queue")
dispatch_async(dispatch_get_main_queue(), { () -> Void in
print("This is run on the main queue, after the previous code in outer block")
})
})
Pre Swift 1.2 -已知问题
从Swift 1.1开始,苹果在没有做一些修改的情况下不支持上述语法。传递qos_class_user_initialized实际上不起作用,而是使用Int(qos_class_user_initialized .value)。
有关更多信息,请参阅apple文档
我真的很喜欢Dan Beaulieu的答案,但是它在Swift 2.2中不起作用,我认为我们可以避免那些讨厌的强制打开!
func backgroundThread(delay: Double = 0.0, background: (() -> Void)? = nil, completion: (() -> Void)? = nil) {
dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INITIATED, 0)) {
background?()
if let completion = completion{
let popTime = dispatch_time(DISPATCH_TIME_NOW, Int64(delay * Double(NSEC_PER_SEC)))
dispatch_after(popTime, dispatch_get_main_queue()) {
completion()
}
}
}
}
在我们的iOS应用中,中央调度是用来处理多任务的。
您可以使用此代码
// Using time interval
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now()+1) {
print("Hello World")
}
// Background thread
queue.sync {
for i in 0..<10 {
print("Hello", i)
}
}
// Main thread
for i in 20..<30 {
print("Hello", i)
}
更多信息请访问这个链接:https://www.programminghub.us/2018/07/integrate-dispatcher-in-swift.html
来自Jameson Quave的教程
斯威夫特2
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), {
//All stuff here
})
斯威夫特5
为了简化,创建一个“DispatchQueue+Extensions.swift”文件,内容如下:
import Foundation
typealias Dispatch = DispatchQueue
extension Dispatch {
static func background(_ task: @escaping () -> ()) {
Dispatch.global(qos: .background).async {
task()
}
}
static func main(_ task: @escaping () -> ()) {
Dispatch.main.async {
task()
}
}
}
用法:
Dispatch.background {
// do stuff
Dispatch.main {
// update UI
}
}