NSNotification and NSView problem???

hello everyone,
freshman, , trying make mac application upgrade device, , trouble now. here's question:

project has main window, binds appdelegate controller; , has 2 threads: parent-thread shows view, child-thread b upgrade , on.

between 2 threads, use notification center achieve inter-process communication. when thread b finished doing something, sent notification thread a, , thread change on view, such change values of textfield , on.

question is: view shows correctly, , other times fails show changed ones. how can deal ?

 

maypeng said: ↑

hello everyone,
freshman, , trying make mac application upgrade device, , trouble now. here's question:

project has main window, binds appdelegate controller; , has 2 threads: parent-thread shows view, child-thread b upgrade , on.

between 2 threads, use notification center achieve inter-process communication. when thread b finished doing something, sent notification thread a, , thread change on view, such change values of textfield , on.

question is: view shows correctly, , other times fails show changed ones. how can deal ?

click expand...

don't use nsnotificationcenter communicating between threads. notifications received on same thread in sent, in other words, it's not doing @ want to. nsnotificationcenter more geared towards implementing observer design pattern, not threading.

http://developer.apple.com/library/mac/#documentation/cocoa/reference/foundation/classes/nsnotificationcenter_class/reference/reference.html

quote

in multithreaded application, notifications delivered in thread in notification posted, may not same thread in observer registered itself.

click expand...

you use grand central dispatch schedule block execution on thread a's dispatch queue instead. grand central dispatch allow thread b.

code:

 /* in thread b */ dispatch_async(dispatch_get_main_queue(), ^{   /*   ... code want execute on thread ... */ }); 

alternatively can use nsobject's method perform selector on main thread.

http://developer.apple.com/library/mac/#documentation/cocoa/reference/foundation/classes/nsobject_class/reference/reference.html

code:

 - (void)performselectoronmainthread:(sel)aselector withobject:(id)arg waituntildone:(bool)wait modes:(nsarray *)array 

both methods going work queuing message on application's run loop on main thread execution @ later time.

there might other methods accomplishing well. anybody?

 

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