如何在使用DispatchQueue时停止从主线程快速执行正在运行的后台线程 [英] How to stop execution of a running background thread from main thread on swift while using DispatchQueue
本文介绍了如何在使用DispatchQueue时停止从主线程快速执行正在运行的后台线程的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
DispatchQueue.global(qos: .background).async {
//This will run on the background queue
self.writeValue(tag: GlobalData.WRITE_DATA, data: getDataForWrite(1) )
self.writeValue(tag: GlobalData.WRITE_DATA, data: getDataForWrite(2) )
self.writeValue(tag: GlobalData.WRITE_DATA, data: getDataForWrite(3) )
self.writeValue(tag: GlobalData.WRITE_DATA, data: getDataForWrite(4) )
self.writeValue(tag: GlobalData.WRITE_DATA, data: getDataForWrite(5) )
// .....
DispatchQueue.main.async {
//This will run on the main queue, after the previous code in outer block
print("done writing data")
}
}
我需要停止从主线程执行此线程.怎么可能
I need to stop executing this thread from the main thread. How is it possible
推荐答案
我认为最好的解决方案是在 async
中执行 DispatchWorkItem
:
I think the best solution is to execute DispatchWorkItem
in async
:
DispatchWorkItem封装了可以执行的工作.可以将工作项分派到DispatchQueue上和DispatchGroup中
DispatchWorkItem encapsulates work that can be performed. A work item can be dispatched onto a DispatchQueue and within a DispatchGroup
所以最后您的代码可能是:
so at the end your code might be:
let workItem = DispatchWorkItem {
//.... writing stuff in background ....
DispatchQueue.main.async {
//.... done writing stuff, updating ui ....
}
}
DispatchQueue.global().async(execute: workItem)
当您需要停止执行时,只需调用 .cancel()
:
when you need to stop the execution just call .cancel()
:
//.... but, if stuff goes wrong ....
DispatchQueue.main.async {
workItem.cancel()
}
这篇关于如何在使用DispatchQueue时停止从主线程快速执行正在运行的后台线程的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文