I'm using the latest stable releases of Mono/Monotouch/MonoDevelop on a iOS 5.0 iPhone and iPad. I have a UIWebView that in the emulator never crashes however randomly on the actual devices it crashes on EXC_BAD_ACCESS. Based on everything I've read with UIWebViews that most likely occurs when the UIWebView gets disposed before it finishes loading.
Here is the code I am using in my ViewDidLoad():
var urlAddress = BASE_URL + _page;
var nsURL = new NSUrl(urlAddress);
var nsURLRequest = new NSUrlRequest(nsURL);
_webView.Tag = 10;
_webView.ScalesPageToFit = true;
_webView.AutosizesSubviews = true;
_webView.LoadStarted += HandleWebViewLoadStarted;
_webView.LoadFinished += HandleWebViewLoadFinished;
_webView.LoadRequest(nsURLRequest);
this.Add(_webView);
Any ideas why it would crash on the actual device randomly, but never in the emulator?
I would need to see the crash details and a but more of source code to be 100% certain but I do believe it's caused because your NSUrlRequest instance is declared as a local variable. Promote this variable into a field of your type should solve this.
The instance could still be required once the method is completed it's execution. However at that time it's not referenced anymore and the garbage collector can collect it anytime. If collected then you'll likely get a crash like you mentioned.
The fact it does not occur on the simulator is likely caused because it's faster (than the device) and the code can complete before the GC collect that instance. IOW it could crash it's just a timing thing that makes it work most of the time on the simulator and almost never on devices.
Related
I take over some legacy code, and there's a code snippet like this
let albumGroups = data.getJSONArray("groups")
let groupNum = albumGroups.length()
var album: JSONObject
for i in 0..<groupNum
{
album = albumGroups.getJSONObject(i)
orderSummary.album.name[i] = album.getString("name")
}
It runs without any issue when the app is built in Debug mode.
But if it is built in Release mode, it crashes at album.getString("name") when i is 1. The error shows that the album variable was deallocated.
I tried running the app with Address Sanitizer flag enabled.
My question is, as far as I know, the album variable is out of the loop's scope, why it was deallocated after the first loop ended?
Check that orderSummary.album isn't a weak reference. If it is, the Album you initialize on line 1 is destroyed immediately, which would explain the crash when you attempt to set orderSummary.album.name[i].
I'm trying to track down a memory-related crash in my game. The exact error, if I happen to catch it while attached to a debugger varies. One such error message is:
Message from debugger: Terminated due to memory issue.
No crash report is generated. Here's a screenshot from the XCode7 Memory Report as I play on my iPhone6; after about 10 minutes it will crash, as I enter into the ~600MB+ range:
Running generational analysis with Instruments I've found that playing through battles appears to create unbounded persistent memory growth; here you can see what happens as I play through two battles:
What is confusing is that the allocations revealed by the twirl-down are pretty much every single bit of allocated memory in the whole game. Any read of a string from a dictionary, any allocation of an array, appears in this twirl-down. Here's a representitive example from drilling into an NSArray caller-analysis:
At this point, it occurs to me I started this project using cocos2d-iphone v2.1 a couple of years ago, and I started an ARC project despite using a pre-ARC library. I'm wondering if I'm just now realizing I configured something horribly, horribly wrong. I set the -fno-objc-arc flag on the cocos2d files:
Either that, or I must have done something else very very stupid. But I'm at a loss. I've checked some of the usual culprits, for example:
Put a NSLog in dealloc on my CCScene subclass to make sure scenes were going away
Made sure to implement cleanup (to empty cached CCNodes) and call super in my sublcasses
Dumped the cocos2d texture cache size, and checked it was not growing unbounded
Added low memory warning handlers, doing things like clearing the cocos2d cache
I've also been pouring over the Apple instruments documentation, in particular this link explains the steps I took to create the above generational analysis.
Update
Here's another representative example, this time in tree format. You can see that I have a CCScheduler which called an update function which triggered the UI to draw a sprite. The last time you see my code, before it delves into cocos2d code, is the highlighted function, the code for which I've also pasted below.
+ (instancetype)spriteAssetSource:(NSString*)assetName {
if(!assetName.length) {
return nil;
}
BOOL hasImageSuffix = [assetName hasSuffix:EXT_IMG];
NSString *frameName = hasImageSuffix ? [assetName substringToIndex:assetName.length-EXT_IMG.length] : assetName;
NSString *hdFrameName = [NSString stringWithFormat:#"%#%#",frameName,EXT_HD];
// First, hit up the sprite sheets...
if([[CCSpriteFrameCache sharedSpriteFrameCache] hasSpriteFrameName:hdFrameName]) {
CCSpriteFrame *frame = [[CCSpriteFrameCache sharedSpriteFrameCache] spriteFrameByName:hdFrameName];
return [[self alloc] initWithSpriteFrame:frame];
}
// No sprite sheet? Try the assets.
else {
NSString *assetFp = hasImageSuffix ? assetName : [NSString stringWithFormat:#"%#%#",assetName,EXT_IMG];
return [[self alloc] initWithFile:assetFp];
}
}
What's so weird about this is that the captured memory is just the simple line to check if the file name is in the cocos2d cache:
- (BOOL)hasSpriteFrameName:(NSString*)name {
return [_spriteFrames.allKeys containsObject:name];
}
Yet this simple function shows up all over the place in these traces...
What it feels like is that any locally-scoped variable I create and pass into cocos2d gets its retain count incremented, and thus never deallocates (such as the case with both hdFrameName and other variables above).
Update 2
While it's no surprise that the CCScheduler sits at the top of the abandoned objects tree, what is surprising is that some of the objects are completely unrelated to cocos2d or UI. For example, in the highlighted row, all I've done is call a function on AMLocalPlayerData that does a [NSDate date]. The entire line is:
NSTimeInterval now = [NSDate date].timeIntervalSince1970;
It seems absurd that the NSDate object could be retained somehow here, yet that seems to be what Instruments is suggesting...
Update 3
I tried upgrading my version of cocos2d to 2.2, the last version to exist in the repository. The issue persists.
Getting a strange error from QBFC. This code fails:
var qbRequest = sessionManager.CreateMsgSetRequest("US", 7, 0);
qbRequest.Attributes.OnError = ENRqOnError.roeStop;
var qbQuery = qbRequest.AppendCustomerQueryRq();
// Don't get all fields (would take forever) - just get these...
qbQuery.IncludeRetElementList.Add("ListID");
qbQuery.IncludeRetElementList.Add("Phone");
qbQuery.IncludeRetElementList.Add("AltPhone");
qbQuery.IncludeRetElementList.Add("Fax");
var qbResponses = sessionManager.DoRequests(qbRequest);// <<- EXCEPTION: INVALID TICKET PARAMETER !!!
However - if I just put a delay in there it works fine. e.g.
System.Threading.Thread.Sleep(1000);
var qbResponses = sessionManager.DoRequests(qbRequest);// <<- WORKS FINE!!
I found this out because anytime I would set a breakpoint in the code to debug the problem - the problem would go away. So then I learned that I could just put a 1 second Sleep in there and simulate the same behavior. (btw - half second delay doesn't help - still throws exception)
This has got me scratching my head. I initialize the sessionManager at the start of the app and reuse it throughout my code. And it works everywhere else in this app but here. I have looked at the raw XML (for both request and response) and don't see anything wrong in there. The response just has an error: "The data file is no longer open. Cannot continue." but nothing to indicate why. (and the data file is open, after this exception I can use it for any number of OTHER things)
I suspect it has something to do with WHEN this code is called. I have a listener that listens for messages from the XDMessaging add-in (used for inter-process communication). When the listener receives a message the event calls this code. But this code is called in the same app (and same thread) as tons of OTHER QBFC code I have that does very similar stuff without a problem. And if it was a threading issue I would think the error would happen regardless of if I Sleep() for a second or not.
Anybody have any ideas?
What version of QBSDK are you using and what version of QuickBooks? I tested using QBSDK 13 (though I specified version 7 when creating the message request), with version 14.0 Enterprise R5P. I experienced no problems or exceptions without having a delay. Perhaps there's something going on with your SessionManager since it appears that you've already opened the connection and began the session elsewhere?
Here's my code that had no problem:
QBSessionManager SessionMananger = new QBSessionManager();
SessionMananger.OpenConnection2("Sample", "Sample", ENConnectionType.ctLocalQBD);
SessionMananger.BeginSession("", ENOpenMode.omDontCare);
IMsgSetRequest MsgRequest = SessionMananger.CreateMsgSetRequest("US", 7, 0);
MsgRequest.Attributes.OnError = ENRqOnError.roeStop;
var qbQuery = MsgRequest.AppendCustomerQueryRq();
qbQuery.IncludeRetElementList.Add("ListID");
qbQuery.IncludeRetElementList.Add("Phone");
qbQuery.IncludeRetElementList.Add("AltPhone");
qbQuery.IncludeRetElementList.Add("Fax");
IMsgSetResponse MsgResponse = SessionMananger.DoRequests(MsgRequest);
for (int index = 0; index < MsgResponse.ResponseList.Count; index++)
{
IResponse response = MsgResponse.ResponseList.GetAt(index);
if (response.StatusCode != 0)
{
MessageBox.Show(response.StatusMessage);
}
}
I'm developing an application with adobe air 3 for ios and having low memory errors frequently.
After ios 5 update os started to kill my app after some low memory warnings.
But the thing is profiler says app uses 4 to 9 megs of memory.
There are a lot of bitmap copy operations around and sometimes instantiates new bitmaps from embedded bitmaps.
I highly optimized everything and look for leaks etc.
I watch profiler for memory status and seems like GC clears everything. everything looks perfect but app continues to get low memory errors and gets killed by os.
Is there anything wrong with this code below. Because my assumption is this ClassReference never gets off from memory even the profiles says memory is cleared.
I used clone method to pass value instead of pass by ref. so I guess GC can collect that local variable. I tried with and without clone nothing changes.
If the code below runs 10-15 times with different tile Id's app crashes but with same ID's it continues working.
Is there anyone who is familiar with this kind of thing?
tmp is bitmapData
if (isMoving)
{
tmp=getProxyImage(x,y); //low resolution tile image
}
else
{
strTmp="main_TILE"+getTileID(x,y);
var ClassReference:Class = getDefinitionByName(strTmp) as Class; //full resolution tile image //something wrong here
tmp=new ClassReference().bitmapData.clone(); //something wrong here
ClassReference=null;
}
return tmp.clone();
Thanks for reading. I hope some one has a solution for this.
You are creating three copies of your bitmapdata with this. They will likely get garbage collected eventually, but you probably run out of memory before that happens.
(Here I assume you have embedded your bitmapdata using the [Embed] tag)
tmp = new ClassReference()
// allocates no new memory, class reference already exists
var ClassReference:Class = getDefinitionByName(strTmp) as Class;
// creates a new BitmapAsset from the class reference including it's BitmapData.
// then you clone this bitmapdata, giving you two
tmp = new ClassReference().bitmapData.clone();
// not really necessary since ClassReference goes out of scope anyway, but no harm done
ClassReference=null;
// Makes a third copy of your second copy and returns it.
return tmp.clone();
I would recommend this (assuming you need unique bitmapDatas for each tile)
var ClassReference:Class = getDefinitionByName(strTmp) as Class;
return new ClassReference().bitmapData.clone();
If you don't need unique bitmapDatas, keep static properties with the bitmapDatas on some class and use the same ones all over. That will minimize memory usage.
EDIT: guys, my question was about using the Instruments to see leaks, and the code as an example and side question, but you answered the side question and not the main problem.... Thank you for the answers, but I really need to find out how to work the Instruments with the simulator....
I am learning IOS development, In one of the codes I'm studying i think there is huge memory leak so I've tried learning how to use instruments. As i am learning right now, I am trying to use instruments with the simulator, but all the manuals i found are for connecting to a device and then using instruments and not with the simulator. every thing I've tried doesn't show any leaks in Instruments.
The app doesn't crash because i am guessing the memory leak is not that big, but when i am adding the following code it does crash, why is that, Even when i added the release every time, still crashes....what is wrong with the simulator? or with the code? working with xcode3, not 4.
for (int i = 0; i < 1000000; i++) {
NSString *testLeak = [[NSString alloc] initWithString:#"test1223"];
NSLog(#"%#",testLeak);
[testLeak release];
}
And again, the app crashes and the simulator doesn't show any leaks, even when i put the "attach process" on "iPhone simulator".
NSString *testLeak = [[NSString alloc] initWithString:#"test1223"];
The problem is that you are not actually allocating anything. NSString is internally smart enough to recognize that the above expression does not need to allocate anything because the constant string #"test1223" can neither mutate nor ever be deallocated. Thus, it just returns that string.
If you were to NSLog(#"%p", testLeak); you'd see the same address over and over.
Change the NSString to NSMutableString and you'll likely see the thousands of copies. Maybe; NSMutableString could be optimized to just point to the immutable copy until a mutation operation is performed (implementation detail). Or you could allocate an instance of some class of your own creation.
Keep in mind that Leaks doesn't necessarily show you all leaks; it can't because of the way it works.
For this kind of analysis, Heapshot analysis is very effective.
If it is crashing as described, please (a) post the crash log and (b) file a bug with your app (built for the simulator) attached to http://bugreport.apple.com/.
In general Instruments + Simulator will not be terribly useful; the simulator is only an approximation of what is running on the device.
[something release] doesn't actually free the memory the instant it is called - it just decreases the reference count of an object. If the count is 0, a [something dealloc] is called, and that frees the memory. I guess you are allocating memory faster than the system can free it... besides, doing 1.000.000 allocs in rapid succession instead of single huge one is probably as bad a coding practice as they come...
It may be that some stuff is getting autorelease'd, and that is using a ton of the heap. Try changing your code to this:
for (int i = 0; i < 1000000; i++) {
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
NSString *testLeak = [[NSString alloc] initWithString:#"test1223"];
NSLog(#"%#",testLeak);
[testLeak release];
[pool drain];
}
Thank you all, I actualy Found the answer around 4 am yestorday...
when you want to test leaks on the emulator:
rum -> run with Performance Tool ->Leaks
If you select the simulator on the top right as the device to run the app on, It will lounch the simulator and the instruments and start the leak recorder, all in one click....
Have fun :-)
Erez