Swift-->GCD,NSThread,NSBlockOperation多线程使用(主线程回调)

应用程序开发,少不了的多线程,与多线程相关的就是线程同步.
本文介绍Swift最简单的多线程使用.

看例子:

1:获取线程基本的信息

func getThreadInfo() {
    let thread = NSThread.currentThread()
    let threadInfo = "线程名:\(thread.name)\n" +
        "堆栈大小:\(thread.stackSize)\n" +
        "优先级:\(thread.threadPriority)\n" +
        "是否是主线程:\(thread.isMainThread)\n" +
        "地址:\(NSThread.callStackReturnAddresses().first)-\(NSThread.callStackReturnAddresses().last!)"
}

2:子线程的创建方法

// MARK: 手动创建线程,并且手动开始线程
func createSingleThread() {
    NSThread(target: self,selector: #selector(onThreadRun),object: nil).start()
}

// MARK: 创建线程并自动开始线程
func createAndStartThread() {
    NSThread.detachNewThreadSelector(#selector(onThreadRun),toTarget: self,withObject: nil)
}

3:GCD(Grand Central Dispatch)队列的使用

// MARK:添加一个block到主线程队列,注意会阻塞当前线程,等待当前队列任务执行完,才会执行block
func gcdMainQueueSync() {
    dispatch_sync(dispatch_get_main_queue()) {
        print("main_sync")
        self.getThreadInfo()
    }
}

// MARK: 添加一个block到主队列,异步执行,不会阻塞当前线程
func gcdMainQueueAsync() {
    dispatch_async(dispatch_get_main_queue()) {
        print("main_async")
        self.getThreadInfo()
    }
}

4:自定义queue

// MARK: 自定义一个同步队列
func gcdCustomSerialQueue() {
    let queue = dispatch_queue_create("serial_queue",DISPATCH_QUEUE_SERIAL)
    // 同步调用,当前线程执行
// dispatch_sync(queue) {
// print("custom_queue")
// self.getThreadInfo()
// }
    // 异步调用,子线程执行
    dispatch_async(queue) {
        print("custom_queue")
        self.getThreadInfo()
    }
}

// MARK: 自定义一个异步队列
func gcdCustomConcurrentQueue() {
    let queue = dispatch_queue_create("serial_queue",DISPATCH_QUEUE_CONCURRENT)
// dispatch_sync(queue) {
// print("custom_queue")
// self.getThreadInfo()
// }
    dispatch_async(queue) {
        print("custom_queue")
        self.getThreadInfo()
    }
}

5:NSBlockOperation和NSOperationQueue的使用

// MARK: ns block 会在当前线程执行,并且是一个 并行队列
func blockOperation() {
    // 并行队列,多任务会同时进行
// NSBlockOperation {
// print("blockOperation")
// self.getThreadInfo()
// }.start()

    let block = NSBlockOperation {
        print("blockOperation1")
        self.getThreadInfo()
    }
    block.addExecutionBlock {
        print("blockOperation2")
        self.getThreadInfo()
    }
    block.addExecutionBlock {
        print("blockOperation3")
        self.getThreadInfo()
    }
    block.start() // 并行执行1,2,3个任务,执行顺序不保证
}

// MARK: 添加到队列的block会立即执行,
func blockOperationQueue() {
    let queue = NSOperationQueue()
// queue.addOperationWithBlock {
// print("blockOperationQueue")
// self.getThreadInfo()
// }

    let operation1 = NSBlockOperation {
        print("operation1")
        self.getThreadInfo()
    }
    let operation2 = NSBlockOperation {
        print("operation2")
        self.getThreadInfo()
    }
    let operation3 = NSBlockOperation {
        print("operation3")
        self.getThreadInfo()
    }
    operation2.addDependency(operation1) // 2会等待1执行完后,再执行
    operation3.addDependency(operation2) // 3会等待2执行完后,再执行
    queue.addOperations([operation1,operation2,operation3],waitUntilFinished: true) //
}

6:子线程调用,主线程执行(必备技能,更新UI的首选)

// MARK: 一定在主线程回调
func mainThread() {
    // 1->在主线程的队列执行
    dispatch_async(dispatch_get_main_queue()) {
        print("dispatch_async")
        self.getThreadInfo()
    }

    // 2->在主线程执行
    NSOperationQueue.mainQueue().addOperationWithBlock {
        print("mainQueue")
        self.getThreadInfo()
    }
}

通常,我都是这样使用子线程的:

NSOperationQueue().addOperationWithBlock {
    print("runOnThread")
    self.getThreadInfo()
}

源码: https://github.com/angcyo/ThreadDemo

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Swift-->GCD,NSThread,NSBlockOperation多线程使用(主线程回调)

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