在Swift中创建带参数的线程？

Question

我试图在swift中创建一个线程并发送两个参数.我创建线程和这项工作:

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dispatch_async用于调用getData后台队列:

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

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

请记住,如果getData实际上return是数据,那么你将不得不处理内部dispatch_async的闭包:

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 !! */

如果您打算在iOS上进行多线程/并发编程,我强烈建议您查看Apple的并发编程指南.