In my app, when I press a button the method called for that button first assigns my textfield texts directly to NSArray object like:
val = [[NSArray alloc] initWithObjects: nameText.text, cellText.text, p_emText.text,
p_cnfrmText.text, s_emText.text, s_cnfrmText.text,
emailText.text, ecnfrmText.text, lat, longt,
nil];
when I run my app on simulator no app crashing occurs, but when I run it on my iPhone device it gives: Thread 1: program recieved signal "EXC_BAC_ACCESS"
Can anybody tell why this happens and what's the solution for this scenario?
In XCode, go to menu "edit scheme", choose the running configuration and add 'NSZombieEnabled' like in the picture below, when your apps crashes, it will provide you additional infos on the crash that should help you debug it.
EDIT
Note that when your application debug is over, remove the NSZombieEnabled command as it impacts the application performances
All objects involved in array creation using initWithObjects should be actual objects. There is no enough code in your question to know if lat and longt are objects too. Are they?
If they aren't, wrap them with [NSNumber numberWithFloa:<# the float #>].
If that's not the problem, check SO questions regarding EXC_BAC_ACCESS to learn to debug them.
Delete the app from simulator/ delete the build file from Mac/ clean the product from XCode and then again run it in simulator. Check if it crashes in simulator now.
Take a look at this link : EXC_BAD_ACCESS signal received. Also, Take NSLog of all the textfield.texts before putting them in array. May be one of them has become nil.
it may be a case of memory managemnet...have you released all the objects after their use?
simulator has the memory space of whole of the machine...but iphone has a defined memory of a sandbox for a single app.
Most probably your app is crashing due to memory issues since it is not crashing in simulator, try to release all objects that you allocate at the points you are done with them.
If you have your custom objects which you allocate and initialize as;
MyCustomClass *myObject = [[MyCustomClass alloc] init];
you need to release them as
[myObject release];
especially if they have members which are assigned big sized images or other kind of data.
If your app starts to crash less after you start solving these memory management issues, it shows that you are on the right way. So keep releasing.
Related
I am testing backward compatibility of an app before submitting it to the app store.
iOS 5 devices run the app great, but now I'm testing on an old iPod touch with iOS 4.2.1.
What Goes Wrong:
At one point (always the same point), the app just hangs - it doesn't crash, just freezes so I'm thinking it's not a lack of memory causing it.
No errors are displayed, however following the code by setting breakpoints results in this line:
myWebView = [[UIWebView alloc] initWithFrame:webFrame];
running but never finishing.
So:
What might be going wrong, what can I do to further get more info/logs about what may be happening? Any ideas are much appreciated, thanks!
Make sure that you don't have duplicate entries like instance variable and property for "_myWebView" and "myWebView". Try to use _myWebView.
Try to remove assignment statement and see if it works then problem is duplicating ivar and property.
I have some code that returns a struct containing 2 objects (declared as id).
When trying to use one of the objects I get an EXC_BAD_ACCESS and the app crashes. This only happens on the device (ipad) not in the simulator.
I have set NSZombieEnabled to YES, however no information is written to the console.
I don't know if it's a problem that I'm using a workspace in Xcode 4, one project for my app, and another that builds a library which is used in my app. The EXC_BAD_ACCESS is occurring in the second project, so I don't know if NSZombieEnabled will apply to the second project?
How do I solve this? Especially as I it only happens on the device (even goes as planned on the simulator), and it is in the second project?
EDIT: This is the method where the EXC_BAD_ACCESS occurs, on line 62, on sortRange.lower –
NSZombieEnabled only works on the simulator, not on the device, so it's probably hiding the problem. Run Product > Analyze (⇧⌘B) for clues. It's harder to say more without looking at the code. As Mihai says, your objects are probably over released, which is the most common cause of EXC_BAD_ACCESS.
It seems that one of your objects is autoreleased before you are trying to access it. As the iPad has less memory than the computer you are running it on it get's released faster so that's why it's not available. Try NSLog both objects just before the line you are getting the error and see wich one of them is the problem and than trace back to it's origin and retain it somehow. Also don't forget to release it after you are done using it. Some example code would be useful.
I thought that I was really close to release this new App of mine when I ran into a dead end. My code works without memory leaks in the simulator (Xcode 4.0.2) but reports memory leaks on my devices.
I think my issue is related to that I copy an object, because in my troubleshooting attempts I tried without a copy, and then the memory leak goes away (but of course so do my functionality!).
What I do is that I add a number of instances of a subclass of UIView to an array . This subclass(Cities of which cityToAdd is an instance) has two UIViews and some variables that I need to access at a later stage.
If I do this I get memory leaks on my devices:
[arrayOfCities addObject:[[cityToAdd mutableCopy] autorelease]];
But if I do this I don't (but loose functionality)
[arrayOfCities addObject:cityToAdd];
In the subclass I have this to handle the copying:
- (id)mutableCopyWithZone:(NSZone *)zone{
Cities *newCity = [[Cities allocWithZone:zone] init];
[newCity initWithCityName:cityName
onRing:ring
withTimeZone:timeZone
withTimeZoneOffset:timeZoneOffset
withDSTAngle:DSTAngle
andDST:isDST];
return newCity;
}
From Instruments I get this when testing on a device:
and when I drill down on the second row it shows this:
Finally my initWithCityName method (sorry for such a long post!!) I put it as a picture to get the colors and messages from Instruments...
Finally the UIIMage imageNamedUniversal is an extension to give me #2x images on the iPad (but I have tried with the normal imageNamed and get the same memory leaks).
I dont know where to start!! Appreciate any ideas.
Thanks
Why are you calling two initialization methods? You are calling init and initWithCityName....
Two things to consider:
After you add cityView and DSTView as subviews, you can and should release them.
And you are initializing newCity twice in your copyWithZone.
Thanks for fast replies and suggestions. You got me on the right track. The cityToAdd that I added to my array was added several times in a loop, but I kept the alloc and init outside of the loop. Once I moved it inside the loop it works in both simulator and device.
Weird that the simulator don't report that memory leak though...
Again, thanks for your fast replies!
Good Day,
I'm completely inexperienced in checking for memory leaks and so any help with this would be great.
I've just finished the bulk of the work for my iPhone app and I'm now trying to figure out why it stops working after a couple of runs. Using Instruments in Leaks and Allocations mode I can see there are two objects that are piling up memory quite quickly and not releasing:
I'm not a hundred percent sure where or why this is happening, but when I clicked on the arrow to the right of UIDeviceRGBColor the Responsible Caller is stated as
[UIColor allocWithZone];
I did a search through my project for UIColor and came up this (take note of _colorThreshold):
I believe my problem has to do with _colorThreshold which doesn't seem to be getting released:
I've tried adding autorelease to their initialisation arguments, but that made the app crash. Any advice here?
EDIT 1
Here is the screen shot from LevelMeter.h
There are several issues with the above:
Is LevelMeterColorThreshold an Objective-C class?
If so, why are you using malloc instead of the usual alloc/init?
As you pasted screenshots of your search results, we cannot see the surrounding code, as only lines with search hits are displayed.
Does the Leaks instrument report leaks, or are you just allocating unnecessary memory?
There is a difference between those two cases:
A leak happens if you loose reference to an object so that you cannot send it a release message later.
Instantiating objects, that aren't needed anymore without releasing/freeing them
Leaks can only detect the first case.
Sample for a leak:
NSMutableString* test = [[NSMutableString alloc] initWithString:#"1"];
NSLog(#"%#", test);
NSMutableString* anotherTest = [[NSMutableString alloc] initWithString:#"2"];
test = anotherTest; //here we loose reference to the original object
NSLog(#"%#", test);
By assigning anotherTest to test, we have lost the reference that points to the memory address that contains #"1".
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.