标签: nsoperationqueue

我有一个带有表视图的导航视图,当单击一行时,行indexPath将传递给下一个视图.

在Details视图viewDidLoad中,我从Core Data获取数据.我使用应用程序委托中的提取

[appDelegate loadItem:i];

正如您所看到的,我只传递一个带有行号的整数.

问题是:如何在另一个线程中进行此调用过程.(在后台)我需要这个,因为有时获取的结果太大,因此处理需要3秒延迟推送详细信息视图.

我需要显示三秒的活动指示器,所以我需要将Fetch放在另一个线程中,以便在处理提取时能够使用指示器的UI.

我想要最简单的方式,因为我是新手.发布一些代码会很棒.或链接:)

我在NSOperationQueue中运行了NSOperation.NSOperation下载一些数据并将其解析为NSDictionary.我如何知道NSOperation何时完成并获得该字典？谢谢.

我正在尝试在NSOperationQueue设置的线程上运行NSTimer

-(void)apiCallbackQueueManager:(NSString *)callid :(NSString *)service:(NSString *)action:(NSString *)data{

SEL theSelector = @selector(apiCallbackQueueTimer: service: action: data:);
NSMethodSignature * sig = [self methodSignatureForSelector:theSelector];
NSInvocation * theInvocation = [NSInvocation invocationWithMethodSignature:sig];
[theInvocation setTarget: self];
[theInvocation setSelector: theSelector];
[theInvocation setArgument: &callid atIndex: 2];
[theInvocation setArgument: &service atIndex: 3];
[theInvocation setArgument: &action atIndex: 4];
[theInvocation setArgument: &data atIndex: 5];

NSInvocationOperation* operation = [[NSInvocationOperation alloc] initWithInvocation:theInvocation];
NSOperationQueue *apiQueue = [[NSOperationQueue alloc] init];
[apiQueue addOperation:operation];
 }

-(void)apiCallbackQueueTimer:(NSString *)arg1 service:(NSString *)arg2 action:(NSString *)arg3 data:(NSString *)arg4{
apiTimer =  [NSTimer scheduledTimerWithTimeInterval:1.0 target:self …

我正在使用NSOperation(s)下载文件并添加它们NSOperationQueue.NSOperationQueue当应用程序进入后台时,它会被暂停.如果队列不在后台暂停并开始下一个操作,是否有任何解决方法？

我的网络活动指示器有问题,有时它会在不应该显示时继续显示.

我为它编写了我自己的经理并将其换成了一个使用这样的NSAssert语句的人...

- (void)setNetworkActivityIndicatorVisible:(BOOL)setVisible {
    static NSInteger NumberOfCallsToSetVisible = 0;
    if (setVisible)
        NumberOfCallsToSetVisible++;
    else
        NumberOfCallsToSetVisible--;

    // The assertion helps to find programmer errors in activity indicator management.
    // Since a negative NumberOfCallsToSetVisible is not a fatal error,
    // it should probably be removed from production code.
    NSAssert(NumberOfCallsToSetVisible >= 0, @"Network Activity Indicator was asked to hide more often than shown");

    // Display the indicator as long as our static counter is > 0.
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:(NumberOfCallsToSetVisible > 0)]; …

我写了以下类别 NSOperationBlock

@implementation NSOperationQueue (Extensions)

-(void)addAsynchronousOperationWithBlock:(void (^)(block))operationBlock
{
    dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);

    block signal = ^ {
        dispatch_semaphore_signal(semaphore);
    };

    [self addOperationWithBlock:^{
        operationBlock(signal);
        dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
        dispatch_release(semaphore);
    }];
}

@end

它似乎工作正常,但当我调用它时(如下面的代码段所示)我得到一个警告:

阻止可能会导致保留周期

[_queue addAsynchronousOperationWithBlock:^(block signal) {
        [self foo:nil];
         signal();
}];

foo 是使用此类别的类的方法.

与addOperationWithBlock:(from NSOperationQueue)相同的代码不显示警告:

[_queue addOperationWithBlock:^ {
        [self foo:nil];
}];

我真的不明白.特别是我不明白的是:我是否应该在两种情况下都使用弱指针？实际上,如果我不使用弱指针,两个片段会带来保留周期吗？

这是我的应用场景:当用户滑动通知时,我将通过URL启动一些其他应用.因此,当通知到达时,它基本上会启动其他应用程序.

目前处理滑动通知方案的时候

- (BOOL)application:(UIApplication *)app didFinishLaunchingWithOptions:(NSDictionary *)

方法被调用,在这个方法中,我调用processNotification:方法,其中包含:

...
[[UIApplication sharedApplication] openURL:url];
...

• 如果在app激活时收到推送,url则打开完全正常.
• 如果通过滑动或点击通知收到推送,url则在后台打开,但当前查看的应用程序是我的应用程序.例如,如果我url是tel:123-456-7890,iOS启动呼叫(你可以听到声音)但活动的应用程序不是Phone.app,它是我的应用程序.

这对我来说似乎很奇怪.但是,如果我等待UI加载,然后调用processNotification:它,它会Phone.app正确显示窗口.(平台中的错误？因为调用发生但我的UI位于顶部.)

我需要一种方法来延迟执行此processNotification:调用(可能通过操作队列),直到加载视图控制器.否则,我的应用程序将保持在最顶层,并在后台打开URL.

说我想实现这样的模式:

a = some array I download from the internet
b = manipulate a somehow (long operation)
c = first object of b

这些显然需要同步调用,这导致我在目标C中出现问题.我读过NSOperationQueueGCD,我不太了解它们,或者哪些适合这里.有人可以建议一个解决方案？我知道我也可以使用performSelector:@selector(sel)WaitUntilDone,但对于大型操作而言,这似乎并不高效.

这是我的代码:

@interface MyObject ()
@property(nonatomic) dispatch_queue_t queue;
@end

@implementation MyObject {
    NSThread *_check;
}

- (id)init {
    self = [super init];
    if (self) {
        _queue = dispatch_queue_create("com.Thread.queue", NULL);
        dispatch_async(_queue, ^{
            _check = [NSThread currentThread]; //for ex. thread number = 3
            //some code here...
        });
    }

    return self;
}

- (void)someMethod:(MyObjClass *)obj {
    dispatch_async(_queue, ^{
        //need th
        if (_check != [NSThread currentThread]) { // it is sometimes number 3, but sometimes it changes
            NSLog(@"Thread changed.");
        }
        [obj doSmth]; //got crash if …

我尝试NSBlockOperation在完成或取消操作后重新启动，但是出现错误？任何人都知道哪里出错了吗？谢谢

let imageURLs = ["http://www.planetware.com/photos-large/F/france-paris-eiffel-tower.jpg",
    "http://adriatic-lines.com/wp-content/uploads/2015/04/canal-of-Venice.jpg",
    "http://algoos.com/wp-content/uploads/2015/08/ireland-02.jpg",
    "http://bdo.se/wp-content/uploads/2014/01/Stockholm1.jpg"]

class Downloader {

    class func downloadImageWithURL(url:String) -> UIImage! {

        let data = NSData(contentsOfURL: NSURL(string: url)!)
        return UIImage(data: data!)
    }
}

class ViewController: UIViewController {

    @IBOutlet weak var imageView1: UIImageView!
    var indeX = 0

    let operation1 = NSBlockOperation()
    var queue = NSOperationQueue()

    override func viewDidLoad() {
        super.viewDidLoad()
    }
    @IBAction func didClickOnStart(sender: AnyObject) {
        queue = NSOperationQueue()

        operation1.addExecutionBlock { () -> Void in

            for _ in imageURLs {
                if !self.operation1.cancelled {
                    let …