Question

我正在尝试在swift中创建一个线程并发送两个参数。我创建线程并且这项工作：

let thread = NSThread(target:self, selector:"getData", object:nil)
thread.start()

但是如何将参数发送到我的func getData？如何使用如下参数创建对象：

let params =...
let thread = NSThread(target:self, selector:"getData", object:params)
thread.start()

...

getData(username: String, password: String) {
    ...
}

Answer 1

您应该使用Grand Central Dispatch而不是直接使用线程。在这种情况下，您希望使用dispatch_async在后台队列上调用getData：

let username = ...
let password = ...

let queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)
dispatch_async(queue) {
    getData(username, password);
}

请注意，如果getData实际上是return个数据，那么您必须处理dispatch_async内部的关闭：

let username = ...
let password = ...

let queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)
dispatch_async(queue) {
    let someData = getData(username, password)
    /* do something with someData */
}

/* !! someData is NOT available here !! */

如果您要在iOS上进行多线程/并发编程，我高度建议您查看Apple的Concurrency Programming Guide。

Answer 2

创建一个类来保存参数怎么样？

class Params {
    username: String
    password: String
    init (#username: String, password: String) {
        self.username = username
        self.password = password
    }
}
// ...
let thread = NSThread(target:self, selector:"getData:", object:Params(username:"xyz", password:"abc")
thread.start()
// ...
func getData(params: Params) {
    // ...
}

Answer 3

使用Swift 5更新

Thread.detachNewThreadSelector(#selector(getData), toTarget: self, with: params)
func getData(params: Params) {
    // ...
}

在Swift中创建带参数的线程？

3 个答案: