When I run my app in Xcode, xcode tells me it is constantly 35% of the CPU, even though it appears that nothing is happening. Nothing is suppose to be happening, so I am surprised by the CPU usage. There is obviously a loop in the code, but I need to figure out how to locate it.
I'm trying to figure out how to locate the loop, perhaps using instruments, but I don't really know where to begin.
Does anyone have any advice on how to attack this problem? I have hit the "pause" button in Xcode, but it of course pauses on the compiled stack (or whatever that screen with a bunch of Hex values is called).
Thanks!
Related
When I try to run my app, it builds with no errors, but will not run.
At the top of the Xcode window it says “Attaching to golfflixlight” with a little animation underneath.
I let it run for 20 minutes and gave up, I'm stuck
This is a recurring scourge of Xcode. It is there to make our lives miserable. The solution is very elusive, and I have yet to read a single, coherent explanation what's happening.
Take a look at this SO question, it might give you some idea how to solve your conundrum. Personally, nothing works for me other than going to Edit Scheme, and setting the debugger to GDB. Good luck.
I'm making an iPhone RPG application, I was working on programming a CGPoint array to some sprites I wanted to add, but I didn't make any progress and thus deleted the code.
After this, an exception was thrown each time I ran the app' on the iPhone Simulator, it said it was to do with OpenAL, so I took all of the sound code out.
The project then ran fine on the iPhone Simulator, without sound though of course.
Now, upon taking all of my newly added code out, the iPhone Simulator crashes (freezes) when it's still on the Cocos2d load up screen and points to the following line of code in Xcode:
int retVal = UIApplicationMain(argc, argv, nil, #"AppDelegate");
I've been looking over my code with a fine-tooth comb for an hour now, checking in case I left any code in or changed anything, and I haven't.
Has anyone had any experience with this problem? Or can anyone give me an idea what might have happened?
Some light to shine on the OpenAL problem would be nice too (second time it's happened to me).
The best thing to do in situations such as these is put break points all over the place and look for the point at which the applications crashes from.
If you haven't yet check out the stack for any clues. Unfortunately if there is nothing on the stack or printed from the debugger this is really all you can do.
So I checked some other questions AGAIN, and found someone saying to restart the computer... This worked. It's annoying, so so annoying. But that's what worked.
Also, for any weird errors, just make sure you Product > Clean after adding/changing any resources you use.
I'm programming an application for iPhone. My application has a login system. In the login system (and somewhere around my app) I have some placeholder in the UITextFields.
After a couple of months working on this app, I noticed a sudden problem that arose once. If I don't write in the text fields that have placeholders nothing happens, if I write something in them, the blue bar that blinks showing where you are in the text becomes very slow. Moreover the ScrollViews that I have become EXTREMELY slow. Some other strange behavior happens when I have a wheel that lets the user pick some choice: the options of the wheel "fall" from the sky while the user rolls it.
All of this happens only if I write something in a UITextField that has some placeholder. If not, nothing of this happens.
I know this sounds REALLY strange, I used a MacOSX program to create a video of the text field becoming slow.
It's .swf.
try to do one thing.. delete this textfiled and create a new one with different name and see is this problem occurring again? also try to set breakpoints in your code and debug your code.
Are you sure you aren't leaking any memory or running an endless loop on the cpu? Try monitoring your app with Instruments and check your cpu activity and memory allocations.
I have an app that has a tabBar Controller and a navBar Controller. It has ~8 views (a variety of web, table, standard, mail, address etc.), some created using IB some created using XCode to make the table views. I've ran the memory leak tester and it doesn't have memory leaks. It can crash at anytime on any of the views, If I flip back and forth between views and use some of the functions it closes the app.
I assume that either I am running 1) out of memory or 2) not releasing views correctly, which causes the app to close. The app is simple so I don't know how I could be out of memory and I've reviewed the code to the best of my ability for releasing the objects correctly.
So Here is my list of questions:
1) What and How to use some of the other debugging tools (or tell me what tools/files I should be looking for using)? I would like to narrow down the problem to its source.
2) What is the best practice for releasing these views? How?
3) How much memory do normal apps use? Is there a number that I should stay around? How do I verify that in the simulator? the Allocation tool?
Feel free to point me to apple docs or other stackoverflow questions that can help me.
UPDATE: It appears to only be crashing one view is used, which has a table view with custom cells... The cell are populated from a plist file... this view worked fine a few days ago, I notice that some cells do not have data from the plist file... it could be a plist file problem with not storing proper data. I'll continue to work on it.
UPDATE #2: I went back to older rev of my files, to when this particular tableView worked just fine (pre 3.0) and guess what it works just fine, I change the simulator to 3.0 with this rev of the app and bam crash on this tableView shows up. Thanks for the help so far, I'll try somethings mentioned below and let you know what I find. If you have some tips on why a tableView w/custom cells from 2.2.1 to 3.0 would start crashing, I'll take them. If I can't get anywhere I'll post the code soon. BTW, I mis-spoke above, I thought it wasn't crashing in the simulator... I was wrong it is.
Solution: thanks for the troubleshooting tips the fix was quite simple, but it's odd it didn't crash in 2.2.1... it should have crashed a long time ago for the problem, I was releasing an object one to many times in my custom cell... duh.
On the first and second generation phone's you really don't want to be going over about 20 megs of real memory usage - once you get over that you are at risk of being killed by springboard.
One of the big culprits I've seen is autoreleased memory, since the autorelease pool can hold onto memory a lot longer than you would really like - if you are using a lot of autoreleased objects that can be a potential problem. You can improve this by doing more explicit retain/release where possible and by creating local autorelease pools manually and releasing them after doing a more intensive operation with a lot of autoreleased objects.
The most effective way to keep track of real memory usage I've found so far is running a debug build on a test phone and running with Activity Monitor. That will give you a clear idea of how much memory is getting taken and held onto by your app. As well as how much is being used when it crashes on you.
You can run with Activity Monitor in Xcode on the Run menu -> Start With Performance Tool -> Activity Monitor.
One other very useful tool is the CLang Static Analyzer that you can run against your code base and can give some very helpful memory management information. As mentioned here.
One thing I would try is putting some debug messages into your didReceiveMemoryWarning method(s). That way, if you are running out of memory, you'll at least have some warning.
I'm programming an puzzle game for iPhone using openGL.
There Is one very weird "bug" ( I'm not sure what It is)... whenever I touch the screen a great number of times in a short period of time my app closes, without giving a warning or error.
What could be the cause ?, I guess It has something to do with the memory, but I would like to know.
Edit:
I also think this happens because I'm calling multiple functions every time the user touches the screen or moves his fingers.
Sounds like you're running out of memory.
A few quick tips that might help out:
Check your memory profile over time using Instruments. If you see a steady incline over time, it's likely to be a memory leak, or an inefficient algorithm that is allocating more memory than you need.
Use a static analyzer to help check for leaks, such as Clang.
Images and image-related files are particularly memory-hungry, so focus on efficiency for them. When you work with textures in OpenGL, use the PVRTC format, which offers awesome compression.
didReceiveMemoryWarning: is your friend - aka a good chance to throw out anything you don't absolutely need in memory. Better to be memory-efficient the whole time, though.
Try setting up an NSUncaughtExceptionHandler. You may also want to setup a signal handler.