Question

There is a task needs to draw N images on a NSView. But at the beginning I do not know the amount of images, so I set it works in a thread of background.

 [NSThread detachNewThreadSelector:@selector(workInBackgroundThread:) toTarget:self withObject:nil];

在获得图像数量时,它将发出通知。

- (void)workInBackgroundThread:(id)unusedObject {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

//get image amount....

[[NSNotificationCenter defaultCenter] postNotificationName:@"gotImageAmount" object:nil];

//...
//continue to load images

}

我试图将NSView重新定位,取决于通知职能中的图像数量。

-(void)processGotImagesAmount:(NSNotification*)notification  
{

    //others codes

    [myNSView setFrame:CGRectMake(0,   0, calculateNewWidth, caculatedNewHeight)];//line A

    //others codes

}

但是,当这些评估执行A线时,它冻结了,

[myNSView setFrame:CGRectMake(0,   0, calculateNewWidth, caculatedNewHeight)];

如果我点击一个叫它的人,那就没有问题了。

但它认为它不履行通知职能。

欢迎任何意见

Answer 1

您从背景重新发出通知。

从国家安全局获得 Center docs:

rel=“nofollow noreferer” http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/nsnotificationer_Class/Reference/Reference.html 。

In a multithreaded application, notifications are always delivered in the thread in which the notification was posted

在你的通知中,你重新更新了你从主线上必须完成的内容。要求将该守则移至另一种方法,然后在通知处理守则中将其称作SelectorOnMainThread。

另一种选择是没有通知的幼儿发展。我在S.O.的答复中张贴了样本:

https://stackoverflow.com/questions/7290931/gcd-threads-program-flow-and-ui-updating/7291056#7291056>GCD, Threads, Program flows and UI Updating

友情链接