I have been trying to find out what is causing this crash.
My main view controller has some code like this to start camera picker.
pickerControl = [[UIImagePickerController alloc] init];
pickerControl.sourceType = UIImagePickerControllerSourceTypeCamera;
pickerControl.allowsEditing = NO;
pickerControl.wantsFullScreenLayout = YES;
pickerControl.showsCameraControls = NO;
pickerControl.cameraOverlayView = overlay;
pickerControl.delegate = self;
overlay.delegate = self;
[self presentViewController:pickerControl animated:NO completion:nil];
The overlay is a view with a few buttons at the bottom. one of them is calling back to take picture.. and the call back will call takePicture like below..
[pickerControl takePicture];
I dont know what is causing it, but it crashes immediately after calling takePicture. It doesn't happen all the time.. but it crashes more often.
Please help to understand what is going wrong.
You're asking about beta software that's accessible only after consenting to a non-disclosure agreement. So I'm going to ignore the iOS 7 aspect of the question.
As to getting a crash log, if you already know which method call is crashing then you're not going to get much out of it. But what you can do is use C's signal to install exception handlers for the various exceptions you want to trace.
Upon receiving such an exception, use [NSThread callStackSymbols] to get an array of call stack symbols — a backtrace in effect. You can then hastily write that to disk and, next run, read it back and notify yourself of it accordingly. Services like Crashlytics accumulate them and post them to a server. You could just open an MFMailComposer and send them to yourself as an attachment.
Using the Crashlytics SDK or a similar product directly would allow you to get live, traced crash reports regardless of whether the build has yet been submitted to Apple and without requiring Xcode to do any parsing.
Related
I'm just looking into CefSharp and am confused about NewScreenshot. I've found lots of references to it as well as example code, but none of it works. I found it marked as obsolete in the 63.0 docs...
Has NewScreenshot been removed? If so, what replaces it (how can I tell that the screen has rendered)? For my purposes a blocking (non-async) method would work fine.
Update:
Searching the source for the latest version of CefSharp I find no reference to NewScreenshot.
I started with the Minimal Example that #amaitland referred to. I made a few changes, adapting it for my use. As part of that change I moved the Shutdown() call to the program's destructor.
When I ran the project I received a mystifying error about calling Shutdown() from a thread different than the thread from which Initialize() was called.
Looking through the code I saw ScreenshotAsync and, as I wasn't (knowingly) using another thread, suspected it may be involved. I looked for another way to get my SVG image and found NewScreenshot. Which of course didn't solve my problem, which was that the GC was running my destructor in a different thread (I had no idea that could happen).
At any rate, by this time I'd shucked ScreenshotAsync for NewScreenshot which is how I ended up here.
I set a breakpoint in my handler (which I haven't included as it's never called). Here's what I hope is the relevant code. I've omitted the init code but I believe it's unchanged from the example.
public static void Main()
{
private const string url = "https://www.google.com/";
browser = new ChromiumWebBrowser();
browser.Paint += OnBrowserPaint;
browser.Load(url)
Console.ReadKey();
}
In stepping through the code in the debugger, I set a breakpoint on browser.Load(url). If I examine browser.Paint, I find errors:
Here's the tooltip for DeclaringMethod:
I have no idea if this is related to my event handler not firing, but want to point it out in the event it is involved.
I appreciate your other suggestions but feel I need to find out why an event that should be firing is not.
I'll be happy to reduce and upload the project if it will help. Oh, and thanks for your help!
iOS 6 MKMapView seems to be using the tons of memory, when we starts zooming and playing around with the Map View in our application(for around 7-10 mins), When we come out of the controller which has MKMapView, its some how not releasing the total memory(I am using ARC in my App). I am allocating and initializing the MKMapView thru NIB.
Controller 1 -->Controller 2 (has MKMapView)
1.5MB -->40-60MB (I have used the Instruments to find out leaks, but of no use)
When i come back to Controller1 the live bytes seems to be 7-10MB, after every visit to controller 2 there is around 2-3MB of increment in the Live Bytes, after some time it crashes the application, in console it says "Received Memory Warning". can any one please help? If you need any more info please let me know. Thanks in Advance.
This is because of the way MKMapView works. There's an operation pending, so MapKit is retaining the MKMapView and it hasn't actually been deallocated yet. That isn't itself a problem. The problem is that it's still sending messages to your delegate.
The workaround is simple: As part of your view controller's cleanup set the map view's delegate to nil, which will prevent MKMapView from sending messages to it.
This is documented in MKMapViewDelegate Protocol Reference:
Before releasing an MKMapView object for which you have set a delegate, remember to set that object’s delegate property to nil. One place you can do this is in the dealloc method where you dispose of the map view.
Edit: Give Oscar an upvote as well, just below, who provided the documentation quote here.
Given ARC, I suggest this means you should set your map view's delegate to nil in your view controller's dealloc.
You can do some thing like this which resolves my issue . Change the type of map helps it too.
- (void)applyMapViewMemoryHotFix{
switch (self.mapView.mapView.mapType) {
case MKMapTypeHybrid:
{
self.mapView.mapView.mapType = MKMapTypeStandard;
}
break;
case MKMapTypeStandard:
{
self.mapView.mapView.mapType = MKMapTypeHybrid;
}
break;
default:
break;
}
self.mapView.showsUserLocation = NO;
self.mapView.delegate = nil;
[self.mapView removeFromSuperview];
self.mapView = nil;
}
-(void)viewDidDisappear:(BOOL)animated
{
[self applyMapViewMemoryHotFix];
}
Regularly during my application run, I get
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at mx.managers::SystemManager/stageEventHandler()[C:\autobuild\3.4.0\frameworks\projects\framework\src\mx\managers\SystemManager.as:5649]
This is the full stack trace. Obviously, I guess there is something wrong, but I can't understand what.
Is there any way for me to find the origin of that bad behaviour ?
EDIT
Having added my SDK sources to my debugger, I can now say precisely which line it is :
private function stageEventHandler(event:Event):void
{
if (event.target is Stage)
mouseCatcher.dispatchEvent(event); // This is line 5649
}
mouseCatcher is indeed null. The current event target is indeed a Stage object, and event type contains the "deactivate" String. As event occurs at application startup (before I try to do any kind of user interaction), I guess it's a kind of initialization bug, but where ? and why ?
Look at the source code, this is always your best option. The 3.4 SDK is open source (datavisualization and the flash player itself aside) and you probably already have the source for it in your FlashBuilder/FlexBuilder install/sdks folder. Use grep or windows grep to find the file in question (or find, whatever floats your boat). Open the SystemManager file and check what's happening at that line, check for calls to the method (if it's public use grep again, if it's private you just need to look within the SystemManager). Try to understand why it gets to this point, as pointed out by some others it's likely a timing related issue where you're trying to access something before it has been assigned, in this case the SystemManager, you probably need to defer whatever action you're taking that is causing the error to a later part of the life-cycle (if you're using initialize event or pre-initialize try on creationComplete instead since that will be dispatched after the createChildren method is called).
Note: Mine is located here
C:\CleanFS\SDKs\flex\3.4.0.9271\frameworks\projects\framework\src\mx\managers
In my copy of SystemManager with the version of the SDK I have that line number doesn't make any sense since it's a block closure not an executable line so you'll have to look at your specific version.
It looks like you are using the Flex 3.4 SDK. Are you listening for the ADDED_TO_STAGE event when the application loads? Or doing anything with the Stage object on load? If so, you might be hitting a bug specific to the 3.4 SDK:
http://bugs.adobe.com/jira/browse/SDK-23332
The most obvious solution is to swap out the 3.4 SDK for a later version (3.4A, 3.5 or 3.6). You can do that here: http://opensource.adobe.com/wiki/display/flexsdk/Download+Flex+3
All of your code should be backwards compatable with the newer Flex 3 SDKs.
I can't seem to find the answer to what I would have thought was a common problem.
What I want to do this is:
1. Show the Open File Dialog
2. Process the file selected
3. During processing the file, report progress to the User
I have a file defined, and am using the browseForOpen and AddEventListener:
public var fileInput:File = new File();
fileInput.browseForOpen("Open file",[filter]);
fileInput.addEventListener(Event.SELECT, onFileSelect);
// Step 2 - function gets called to process the file
private function onFileSelect(e:Event):void
{
// Step 3 - do some processing, and at intervals report progress to the screen
}
My issue is - any changes to the screen within the event listener do not get done until the function is complete.
Any help would be appreciated,
Thanks
Start a timer perhaps and let it check status of a variable(that denotes processing progress) as a separate running function it would not be predisposed to waiting on the parent function.
[ to be clear Im saying call a sperate function from the timer.]
But I am inclined to agree with Flextras.com in that most times I have done this the processing was milliseconds so just didnt get seen.
In Step 3, if you are doing some cpu intensive job(like huge xml parsing), then you might be seeing this NOT updating problem. As Flex is single threaded, you better make use of Green threading concept.
You can read about Green Threading here.
I am using MVVM Light and am using Messages to communicate between ViewModels to let a ViewModel know when it is ok to execute something. My problem is that I register for a message and then it receives it multiple times. so to keep from my program executing something more than once I have to create boolean flags to see if it has already been recieved. Any idea why it does this and how I can stop it?
Make sure you unregister your message handlers once you do not need them anymore. The Messenger keeps a reference to the registered methods and this prevents them from being garbage collected.
Therefore, for ViewModels: make sure that you call Cleanup once you done (or implement IDisposable and call Cleanup from there).
For Views (Controls, Windows, or similar) call Messenger.Unregister in an event that occurs on the teardown of the view, e.g. the Unloaded event.
This is a known behaviour of the MVVM and has been discussed in several places.
Very old question but I solved the problem by doing this:
static bool isRegistered = false;
and then, in the constructor:
if( !isRegistered )
{
Messenger.Default.Register<MyMessage>(this, OnMessageReceived);
isRegisterd = true;
}
I have seen this issue before. It had to do with the Messenger.Default.Register being called more than once. The MVVMLight Messenger class will register the same item 'x' number of times. This is why when you call the Send you get it many times.
Anyone know how to prevent MVVMLight from registering multiple times?
really old but thought I would answer just in case somebody needs it. I was fairly new to silverlight at the time and the issue ended up being a memory leak as the viewModel, which had multiple instances, was still in memory.
As other contributors mentioned, the same message is being registered multiple times. I have noticed this behavior taking place while navigating to View X then navigating back to View Z where the message is registered in the constructor of the Z ViewModel. One solution is to set the NavigationCacheMode property to Required
<Page
........
........
NavigationCacheMode="Required">