I have a uiscrollview within three subUIViews 1, 2, 3. I load content for subUIView1, 2,3 dynamically. Here are steps
I create scrollview with these 3
subUIview and with a default size
for each subUIView
I create an operation for each subUIView, let us say Operation 1,2,3. add to operation queue
every Operation (operation 1) calculate the content that will be later draw in related subUIView (subview 1). after calculate completed, create CGLayer and attach it with UISubview1. reset all UIsubviews frame and bound and layout scrollview subviews and setNeedDisplay for related subUIview1. then move to next operation
in SubUIView drawRect method, i call CGLayerDrawInRect.
then occasionly i
get this error Invalid Context.
sometimes, it work fine, no error sometime it happened
Any idea about this error will be welcome.
.
Take a very long time to debug and finally find what is the problem and resolved. Here is the thing
When operation 1 setNeedDisplay sent out, drawRect have not called yet
Once drawRect is called, operation 2 is already running, during drawRect running,operation 2 somehow change subview1,2,3, layout and frame at the same time.
So, the bad thing happened, context will become invalid that time because frame are changing, and also worst, you may receive exe_bad_access false message
Resolve solution, i set a singal to make sure operation 1 drawRect is done then let operation 2 start run.
I have to say XCode is terrible development tools compare what MS studio tools. It gives message like invalid Context or exe_bad_access randomly. where is the productivity for our poor developer. However, Iphone OSX is much better than MS windows mobile. that is why i am working hard to use XCode creatively.
Related
I'm trying to create an agent statechart where a transition should happen every day at 4 pm (except weekends).
I have already tried:
1. a conditional transition (condition: getHourOfDay() == 16)
2: A timeout transition that will "reinsert" my agent into the chart every 1 s and check if time = 16.
My code is still not running, does anyone have any idea how to solve it?
This is my statechart view. Customer is a single resource that is supposed to "get" the products out of my stock everyday at 4pm. It is supposed to happen in the "Active" state.
I have set a timeout transition (from Active-Active) that runs every 1s.
Inside my "Active" state in the "entrance action" i wrote my code to check if it is 4 pm and run my action if so.
I thought since i set a timeout transition it would check my condition every 1s, but apparently it is not working.
Your agent does not enter the Active state via an internal transition.
Redraw the transition to actually go out of the Active state and then enter it again as below:
Don't use condition-based transitions, for performance reasons. In your case, it also never triggers because it is only evaluated when something happens in the model. Incidentally, that is not the case at 4pm.
re your timeout approach: Why would you "reinsert" your agent into its own statechart? Not sure I understand...
Why not set up a schedule or event with your recurrence requirement and make it send a message to the statechart: stateChart.fireEvent("trigger!");. In your statechart, add a message-based transition that waits for this message. This will work.
Be careful to understand the difference between the Statechart.fireEvent() and the Statechart.receiveMessage() functions, though.
PS: and agree with Felipe: please start using SOF the way it is meant, i.e. also mark replies as solved. It helps us but also future users to quickly find solutions :-) cheers
I'm making an iOS 6 program which downloads JSON data from a website and displays it in a table view. I added a pull to refresh method witch works fine. I can go in the settings view controller (secondViewController) and change the address, everything works. Then, I use the pull to refresh method and my tableView is reloaded. But if I reload 3 times AFTER changing the address, my app crashes. I get this error :
*** Terminating app due to uncaught exception 'NSRangeException',
reason: '*** -[__NSArrayM objectAtIndex:]: index 10 beyond bounds for empty array'
*** First throw call stack:
(0x1ca1012 0x10dee7e 0x1c430b4 0x3084 0xdd8fb 0xdd9cf 0xc61bb 0xd6b4b 0x732dd 0x10f26b0 0x229dfc0 0x229233c 0x2292150 0x22100bc 0x2211227 0x22bb333 0x22bb75f 0x1c60376 0x1c5fe06 0x1c47a82 0x1c46f44 0x1c46e1b 0x1bfb7e3 0x1bfb668 0x22ffc 0x1fbd 0x1ee5)
libc++abi.dylib: terminate called throwing an exception
What am I doing wrong ? And how can I fix that problem ? Thanks for your help !
The key design consideration that leaps out is that your retreiveData method is clearly updating the model (the citiesArray) asynchronously, which means that any interaction with the tableview while this is taking place may fail. You should never asynchronously update the actual citiesArray itself. The update to that array should happen in the main queue.
You should change retrieveData to not touch the existing citiesArray, but rather create and return a new array, and then, in the code you dispatch back to the main queue, only then replace the existing citiesArray and call reloadData, something like:
- (void)refresh:(UIRefreshControl *)refreshControl {
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
NSArray *newCitiesArray = [self retreiveData];
dispatch_async(dispatch_get_main_queue(), ^{
if (newCitiesArray) {
// you presumably only want to reload the data if `retrieveData` was successful
citiesArray = newCitiesArray
[myTableView reloadData];
}
[refreshControl endRefreshing];
});
});
}
Clearly, this will involve some changes to retrieveData, too, but hopefully that's self explanatory. If not, update your question with that code, and we can make further suggestions. But we really shouldn't need to go there, as I suspect you understand the change that needs to take place there.
There are other, more subtle issues you might want to tackle, too, such as thinking about whether you really want to use a global queue, which is concurrent (e.g. if you hit refresh while the previous refresh going, do you really want two queries going on concurrently with your server ... because you dispatch the updates back to the main queue you won't crash, but it's inefficient, you're not guaranteed the order that they'll complete, etc.). You might also want to use NSOperationQueue in which you can write code to permit the cancellation of previous requests, etc.
But all of this is a little complicated and is of secondary concern to your main issue, the crashing. Refactoring the retrieveData code to ensure you don't touch citiesArray, itself, as outlined above, should address that.
When I create a new quote from Epicor I would like to add an item from the parts form automatically.
I am trying to do this using the following ABL code which runs when 'GetNewQuoteHed' is called:
run Update.
run GetNewQuoteDtl.
run ChangePartNumMaster("Rod Tube").
ttQuoteDtl.OrderQty = 5.
run Update.
I am getting the error:
Index -1 is either negative or above rows count.
This error occurs for each line in my ABL code.
What am I doing wrong?
That's not the proper format for a 4GL error message (nor is it at all familiar) so I'd say it is an Epicor application message. Epicor support is probably your best bet. However... Just guessing but it sounds like you might need to somehow initialize the thing that you're updating.
Agree with #Tom, but i would also say try and isolate the error and see where the error is raised as soon as you find the point the error is actually raised it is normally much easier to figure out exactly what is going wrong and how to solve it.
Working between a 0 based and a 1 based system there can be issues with the 1st or last entry depending on which way you moving. As the index for 0 based systems starts at 0 and ends at n-1 where 1 based systems start at 1 and end at n.
I have a GPUImageColorDodgeBlend filter with two inputs connected:
A GPUImageVideoCamera which is getting frames from the iPhone video camera.
A GPUImageMovie which is an (MP4) video file that I want to have laid over the live camera feed.
The GPUImageColorDodgeBlend is then connected to two outputs:
A GPUImageImageView to provide a live preview of the blend in action.
A GPUImageMovieWriter to write the movie to storage once a record button is pressed.
Now, before the video starts recording, everything works OK 100% of the time. The GPUImageVideo is blended over the live camera video fine, and no issues or warnings are reported.
However, when the GPUImageMovieWriter starts recording, things start to go wrong randomly. About 80-90% of the time, the GPUImageMovieWriter works perfectly, there are no errors or warnings and the output video is written correctly.
However, about 10-20% of the time (and from what I can see, this is fairly random), things seem to go wrong during the recording process (although the on-screen preview continues to work fine).
Specifically, I start getting hundreds & hundreds of Program appending pixel buffer at time: errors.
This error originates from the - (void)newFrameReadyAtTime:(CMTime)frameTime atIndex:(NSInteger)textureIndex method in GPUImageWriter.
This issue is triggered by problems with the frameTime values that are reported to this method.
From what I can see, the problem is caused by the writer sometimes receiving frames numbered by the video camera (which tend to have extremely high time values like 64616612394291 with a timescale of 1000000000). But, then sometimes the writer gets frames numbered by the GPUImageMovie which are numbered much lower (like 200200 with a timescale of 30000).
It seems that GPUImageWriter is happy as long as the frame values are increasing, but once the frame value decreases, it stops writing and just emits Program appending pixel buffer at time: errors.
I seem to be doing something fairly common, and this hasn't been reported anywhere as a bug, so my questions are (answers to any or all of these are appreciated -- they don't all need to necessarily be answered sequentially as separate questions):
Where do the frameTime values come from -- why does it seem so arbitrary whether the frameTime is numbered according to the GPUImageVideoCamera source or the GPUImageMovie source? Why does it alternative between each -- shouldn't the frame numbering scheme be uniform across all frames?
Am I correct in thinking that this issue is caused by non-increasing frameTimes?
...if so, why does GPUImageView accept and display the frameTimes just fine on the screen 100% of the time, yet GPUImageMovieWriter requires them to be ordered?
...and if so, how can I ensure that the frameTimes that come in are valid? I tried adding if (frameTime.value < previousFrameTime.value) return; to skip any lesser-numbered frames which works -- most of the time. Unfortunately, when I set playsAtActualSpeed on the GPUImageMovie this tends to become far less effective as all the frames end up getting skipped after a certain point.
...or perhaps this is a bug, in which case I'll need to report it on GitHub -- but I'd be interested to know if there's something I've overlooked here in how the frameTimes work.
I've found a potential solution to this issue, which I've implemented as a hack for now, but could conceivably be extended to a proper solution.
I've traced the source of the timing back to GPUImageTwoInputFilter which essentially multiplexes the two input sources into a single output of frames.
In the method - (void)newFrameReadyAtTime:(CMTime)frameTime atIndex:(NSInteger)textureIndex, the filter waits until it has collected a frame from the first source (textureInput == 0) and the second, and then forwards on these frames to its targets.
The problem (the way I see it) is that the method simply uses the frameTime of whichever frame comes in second (excluding the cases of still images for which CMTIME_IS_INDEFINTE(frameTime) == YES which I'm not considering for now because I don't work with still images) which may not always be the same frame (for whatever reason).
The relevant code which checks for both frames and sends them on for processing is as follows:
if ((hasReceivedFirstFrame && hasReceivedSecondFrame) || updatedMovieFrameOppositeStillImage)
{
[super newFrameReadyAtTime:frameTime atIndex:0]; // this line has the problem
hasReceivedFirstFrame = NO;
hasReceivedSecondFrame = NO;
}
What I've done is adjusted the above code to [super newFrameReadyAtTime:firstFrameTime atIndex:0] so that it always uses the frameTime from the first input and totally ignores the frameTime from the second input. So far, it's all working fine like this. (Would still be interested for someone to let me know why this is written this way, given that GPUImageMovieWriter seems to insist on increasing frameTimes, which the method as-is doesn't guarantee.)
Caveat: This will almost certainly break entirely if you work only with still images, in which case you will have CMTIME_IS_INDEFINITE(frameTime) == YES for your first input'sframeTime.
I'm using Three20's TTImageView for it's async image loading + caching.
I've noticed this issue a bunch of times where an image will show up as completely black, and never finish loading. Here's an example of what I'm seeing:
http://screencast.com/t/7O7fnedX5Z2
So...basically I'm wondering if this is a bug in three20, and if so, how I might go about fixing it (is there a patch out there that might fix it)...OR:
Is there a good TTImageView replacement that performs async image loading + caching?
Turns out I was seeing the following in my log:
TTRequestLoader connection:didReceiveResponse:: TTDASSERT failed: 0 == _queue.maxContentLength || contentLength <=_queue\
.maxContentLength
(one for each failed image)
After that, a little bit of googling rendered:
http://groups.google.com/group/three20/browse_thread/thread/8bfac3654a6d9674/caf797f265445971?pli=1
Jeff Verkoeyen:
The comment immediately before that
assert should shed some light on the
situation.
// If you hit this assertion it's because a massive file is about to be downloaded.
// If you're sure you want to do this, add the following line to your app delegate startup
// method. Setting the max content length to zero allows anything to go through. If you just
// want to raise the limit, set it to any positive byte size.
// [[TTURLRequestQueue mainQueue] setMaxContentLength:0]