关于线程顺序执行

1.使用你自己的串行调度队列:

let queue = dispatch_queue_create("com.mycompany.serial-queue",
    dispatch_queue_attr_make_with_qos_class(DISPATCH_QUEUE_SERIAL, QOS_CLASS_USER_INITIATED, 0))

dispatch_async(queue) {
    print("inside block 1")
}

dispatch_async(queue) {
    print("inside block 2")
}

2.使用 NSOperationQueue 与依赖项:

let queue = NSOperationQueue()

let op1 = NSBlockOperation {
    print("inside block 1")
}

let op2 = NSBlockOperation {
    print("inside block 2")
}

op2.addDependency(op1) // op2 may only execute after op1 is finished

queue.addOperation(op1)
queue.addOperation(op2)

3.使用串行 NSOperationQueue:

let queue = NSOperationQueue()
queue.maxConcurrentOperationCount = 1 // execute 1 operation at a time

queue.addOperationWithBlock {
    print("inside block 1")
}

queue.addOperationWithBlock {
    print("inside block 2")
}

赏

谢谢你请我吃糖果

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