var queue: dispatch_queue_t = dispatch_get_main_queue()// 主线程
queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0)// 后台执行
// 异步执行队列任务
dispatch_async(queue, { () -> Void in
print("开新线程执行")
})
// 延时执行
var delta:Int64 = Int64(2 * NSEC_PER_SEC)// 2s后执行,可能不仅限于2s
delta = Int64(100 * NSEC_PER_MSEC)//100毫秒后执行
// NSEC_PER_MSEC
let when: dispatch_time_t = dispatch_time(DISPATCH_TIME_NOW, delta)
dispatch_after(when, queue) { () -> Void in
print("dispatch_after")
}
// 只执行一次
struct Static {
static var onceToken: dispatch_once_t = 0
static var value: String!
}
dispatch_once(&Static.onceToken, { () -> Void in
Static.value = "单例模式"
})
print("(Static.value)")
dispatch_once(&Static.onceToken, { () -> Void in
Static.value = "改变值"
})
print("(Static.value)")
// 分组执行
let group = dispatch_group_create()
queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)// 默认优先级执行
for (var i = 0; i<10; i++) {
//异步执行队列任务
dispatch_group_async(group, queue, { () -> Void in
Static.value = Static.value + "1"
print("(Static.value)")
})
}
// 分组队列执行完毕后执行
dispatch_group_notify(group, queue) { () -> Void in
print("dispatch_group_notify")
}
// 串行队列：只有一个线程，加入到队列中的操作按添加顺序依次执行。
let serialQueue = dispatch_queue_create("yangj", DISPATCH_QUEUE_SERIAL)
for (var i = 0; i<10; i++) {
//异步执行队列任务
dispatch_async(serialQueue, { () -> Void in
//Static.value = Static.value + "1"
//println("(Static.value)")
})
}
// 并发队列：有多个线程，操作进来之后它会将这些队列安排在可用的处理器上，同时保证先进来的任务优先处理。
let globalQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)
for (var i = 0; i<10; i++) {
//异步执行队列任务
dispatch_async(globalQueue, { () -> Void in
//Static.value = Static.value + "1"
//println("(Static.value)")
})
}
}