Re: User interface unresponsive in window
Am I right in thinking that when running under Xcode any drawing errors will be logged to the Xcode console? No, not unless they’re actually exceptions. Messages from other processes are only going to appear in the system log. OK, thanks for your suggestion about checking the system log then - I will look out for that. With puzzling, intermittent errors like this, I often find that reading your own code carefully may be more productive than going to heroic debugging extremes. The trick is not to prejudge *where* in your code you should look. (Don’t be the person looking underneath the street light for a dropped quarter because “that’s where the light is”.) That's a fair suggestion, but taken in its most general sense that is a near-impossible task. There are 100-odd source files in the project, etc, and just code-read the project and look for some bug is a non-starter. Are you effectively saying that you agree with my hypothesis that the cause is GUI-related code being executed on a non-main thread? If you or others have definitely seen that cause problems of this sort in the past, then I'll certainly do a second more thorough read-through of any code that could possibly be relevant... Cheers Jonny ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: User interface unresponsive in window
On 15 Apr 2015, at 16:04, Jonathan Taylor jonathan.tay...@glasgow.ac.uk wrote: I've started encountering intermittent problems in one specific window in my application, where text input boxes become unresponsive, steppers remain highlighted after clicking, etc. I'm rather short of ideas on how to debug this, particular since I haven't worked out how to reproduce it reliably. Other windows seem to remain unaffected. From dimly-remembered past experience I have a feeling it could be related to something somewhere resulting in GUI code being executed on a non-main thread. There is in principle a risk of that, since the window interacts with peripherals/drivers etc involving multithreaded code. I've tried to isolate the GUI code from the multithreaded code, but may perhaps have missed some obscure case. [ideally, I'd probably totally isolate anything multithreaded from ObjC code, but that would mean a proliferation of shadow classes, which is something I'd prefer to avoid being dragged into] Even if my suspicion about the cause (multithreading+GUI) is correct, I'm still not sure how to pin down and debug the problem, since there are so many entry points into GUI-related code (e.g. property value changes), not all of which even involve my own code directly. It would be great if there was some way of enabling a global exception if main-thread requirements are violated, but I certainly haven't heard of such a thing (and can imagine there could be very good reasons why it would be prohibitively hard to implement). Can anyone suggest ways to diagnose and debug my problem (or indeed suggest other possible causes I haven't thought of)? A few ideas: - access of UI from non-main thread, corrupting data - view inserted as subview of one of its superviews - Someone calling one of the nextEventMatchingMask: methods and swallowing events that someone else is looking for to end a loop. - Exception thrown from tracking code - Someone calling display: from inside drawRect:, causing an endless recursion Have you tried just pausing your app in the debugger when this happens and looking at each thread to see what is running? Cheers, -- Uli ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: User interface unresponsive in window
On Fri, Apr 17, 2015, at 04:16 AM, Jonathan Taylor wrote: That's a fair suggestion, but taken in its most general sense that is a near-impossible task. There are 100-odd source files in the project, etc, and just code-read the project and look for some bug is a non-starter. Before you embark on such a task, you might try breaking on -[NSCell drawWithFrame:inView:] or a similar method that you know is being called as part of the badness. The problem there is that you don't know if the issue is at the callsite that triggers the drawing. But it's likely enough that it's worth starting your search there. Are you effectively saying that you agree with my hypothesis that the cause is GUI-related code being executed on a non-main thread? If you or others have definitely seen that cause problems of this sort in the past, then I'll certainly do a second more thorough read-through of any code that could possibly be relevant... You might also have an issue with runloops—either you're touching the UI from a thread that doesn't have a running runloop, or you've got a nested runloop invocation on your main thread, and it's never escaping some special mode (like NSEventTrackingRunLoopMode). Either way, the result is that code sets up a timer or delay-perform that never fires, which might explain the symptoms you're seeing. --Kyle Sluder ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
User interface unresponsive in window
I've started encountering intermittent problems in one specific window in my application, where text input boxes become unresponsive, steppers remain highlighted after clicking, etc. I'm rather short of ideas on how to debug this, particular since I haven't worked out how to reproduce it reliably. Other windows seem to remain unaffected. From dimly-remembered past experience I have a feeling it could be related to something somewhere resulting in GUI code being executed on a non-main thread. There is in principle a risk of that, since the window interacts with peripherals/drivers etc involving multithreaded code. I've tried to isolate the GUI code from the multithreaded code, but may perhaps have missed some obscure case. [ideally, I'd probably totally isolate anything multithreaded from ObjC code, but that would mean a proliferation of shadow classes, which is something I'd prefer to avoid being dragged into] Even if my suspicion about the cause (multithreading+GUI) is correct, I'm still not sure how to pin down and debug the problem, since there are so many entry points into GUI-related code (e.g. property value changes), not all of which even involve my own code directly. It would be great if there was some way of enabling a global exception if main-thread requirements are violated, but I certainly haven't heard of such a thing (and can imagine there could be very good reasons why it would be prohibitively hard to implement). Can anyone suggest ways to diagnose and debug my problem (or indeed suggest other possible causes I haven't thought of)? Thanks in advance Jonny ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: User interface unresponsive in window
On Apr 15, 2015, at 07:04 , Jonathan Taylor jonathan.tay...@glasgow.ac.uk wrote: From dimly-remembered past experience I have a feeling it could be related to something somewhere resulting in GUI code being executed on a non-main thread. You can at least start by trying the simple things, if you haven’t tried them already: — Make sure you have an Objc-C exception breakpoint set in Xcode at all times. — Use the Console utility to look in the system log for errors about incorrect drawing calls in your app. There’s not much chance this will get you off easily, but it’s a quick start. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: User interface unresponsive in window
Thanks for the suggestions. Am I right in thinking that when running under Xcode any drawing errors will be logged to the Xcode console? That's certainly what I've seen in the past (but not in relation to this problem - haven't seen anything in the Xcode console at all for this). Any other ideas from anyone? Has anybody seen similar symptoms ever in the past (GUI not responding properly in one single window)? On 15 Apr 2015, at 18:01, Quincey Morris quinceymor...@rivergatesoftware.com wrote: On Apr 15, 2015, at 07:04 , Jonathan Taylor jonathan.tay...@glasgow.ac.uk wrote: From dimly-remembered past experience I have a feeling it could be related to something somewhere resulting in GUI code being executed on a non-main thread. You can at least start by trying the simple things, if you haven’t tried them already: — Make sure you have an Objc-C exception breakpoint set in Xcode at all times. — Use the Console utility to look in the system log for errors about incorrect drawing calls in your app. There’s not much chance this will get you off easily, but it’s a quick start. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: User interface unresponsive in window
On Apr 15, 2015, at 14:54 , Jonathan Taylor jonathan.tay...@glasgow.ac.uk wrote: Am I right in thinking that when running under Xcode any drawing errors will be logged to the Xcode console? No, not unless they’re actually exceptions. Messages from other processes are only going to appear in the system log. With puzzling, intermittent errors like this, I often find that reading your own code carefully may be more productive than going to heroic debugging extremes. The trick is not to prejudge *where* in your code you should look. (Don’t be the person looking underneath the street light for a dropped quarter because “that’s where the light is”.) ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
