I am new to Objective C and I am trying to make a basic puzzle game. I am using multiple UIImage objects, some labels and a button. It consists in moving the pieces to its correct position. If the user fails to put a piece in a place, the piece goes back to its original location.
That part works perfectly, the problem begins once I 'remove' that view and continue on the other screens. Whenever I click ANYWHERE on screen the views get multiplied endlessly. Why is that happening?
What should I do?, I am so desperate, I've tried almost everything including ignoring touches, blocking touches, etc. And this only creates more trouble.
I have already tried setting using interactions to no, ignoring interaction events, autoreleasing the view, and I have not reached a solution.
Any help will be very much appreciated. Greetings!
---> I tried posting an image but given that I am a newbie I wasn't able to, however I can send the image to anyone if needed to show you the weird effect I get.
-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
[self touchesCancelled:touches withEvent:event];
}
-(IBAction) navigationConversation: (id)sender{
//[self.view.superview setUserInteractionEnabled:NO];
//[[UIApplication sharedApplication] endIgnoringInteractionEvents];
if (nextButton.hidden == NO) {
conversation *navigationConversationController=[[conversation alloc] initWithNibName:#"conversation" bundle:nil];
[self.view addSubview:navigationConversationController.view];
if (self.view.superview == nil)
[navigationConversationController autorelease];
}
return;
}
Thank God, the problem is solved now. This are the changes I made, and this corrected the mistake. :)
-(IBAction) navigationConversation: (id)sender{
if (nextButton.hidden == NO) {
//I disabled the interactions with the puzzle view in here, thus eliminating the problem
[self.view.superview setUserInteractionEnabled:NO];
conversation *navigationConversationController=[[conversation alloc] initWithNibName:#"conversation" bundle:nil];
[self.view addSubview:navigationConversationController.view];
if (self.view.superview == nil)
[navigationConversationController autorelease];
}
return;
}
Thanks to everyone who looked! and wanted to help! I hope this works for other people having the same issues.
Related
So my problem is that after integrating gamecenter nicely into my iphone app, it won't show the achievements list!
The integration was a success I think because when I use the submitAchievement method, I do unlock achievements on the list. But I must look at the list from the GameCenter App on the iPhone, not within my own app as it doesn't work.
ikuragames first help me get the code right (thx you !!) but it still doesn't work ! :(
-(void)showAchievments
{
//NSLog(#"showAchievments");
GKAchievementViewController *achievements = [GKAchievementViewController alloc] init];
if (achievements != nil)
{
achievements.achievementDelegate = self;
[(EAGLView *)self.view achievmentsWillAppear];
[self presentModalViewController:achievements animated:YES];
}
}
- (void)achievementViewControllerDidFinish:(GKAchievementViewController *)viewController
{
//NSLog(#"achievementViewControllerDidFinish");
[glView achievmentsWillDisappear];
[self dismissModalViewControllerAnimated:YES];
}
On debug mode, I can clearly see that each line or code are "processed" and not error whatsoever is displayed. BUT, nothing appears on my screen :(
Can you please help me ? (here is some doc.)
I found the answer.
Turned out that the view controller I was sending showAchievments to was not the view controller I wanted.
I was doing something like:
[[myViewController sharedInstance] showAchievments];
But the sharedInstance method returned a brand-new, vanilla-initialised myViewController, and not the one I was already using.
Now it works perfectly, I hope this will help someone in the future.
I've made a custom zero-image, Core Graphics drawn UIButton based on Ray Wenderlich's Tutorial (the only modifications are to CoolButton's drawRect: method, altered drawing code), and it works great most of the time. However, sometimes when I click it for a short period of time, it stays in a depressed state and doesn't return to normal.
From here, the only way to get it back to a normal state is via a long press. Simply clicking means it stays depressed.
Another thing to note is that I've hooked Touch Up Inside up to a chain of a few long methods - I don't think it would take more than 0.1 seconds to complete. I've even used dispatch_async in the #selector that is hooked up to Touch Up Inside, so there shouldn't be a delay in the UI updating, I think.
I've put an NSLog in the drawRect: which fires 3 times per button press usually, and it varies what UIControlState the button is in for each press:
For some short presses, it goes Highlighted, Highlighted, Normal
for longer presses, it's Highlighted, Normal, Normal
However, for very short presses, it only fires twice, Highlighted -> Highlighted.
When it's a long press to get it back to Normal, it goes H, N, N.
This has been puzzling me for a while, and I haven't been able to work out why short presses only fire drawRect: twice, or why touchesEnded: doesn't seem to call drawRect:. Perhaps touchesEnded: isn't firing?
I really hope someone can help.
If you really want to generate the button images at runtime, generate them when the button is loaded. Then add them for different states using
[button setImage:btnImage forState:UIControlStateNormal];
You can always turn a view into an image using the following: http://pastie.org/244916
Really though, I'd recommend just making images beforehand. If you don't want to get photoshop, there's plenty of alternatives. The upcoming pixelmator update looks pretty suave, ands it's ridiculously cheap!
Well, well, that was easy. 0.15 second delay works, 0.1 doesn't.
As other said, you can simply generate an image and use that as background (if the image is static). No need photoshop, you may simply generate your image once and then take a snapshot, then cut the image out (with Anteprima) and save it as a png file :)
However, since you said the button is connected to some long methods, this may be why the button stay pressed: if you are not calling those methods in background, then the button will stay pressed since all the task are ended. Try (for a test) to connect the button with a single simple method (say NSLog something) and check if it stay pressed. If not, I suggest to detach your methods in background.
I too ran into a similar problem with a UIButton appearing to stick one state when I customize the drawRect method. My hunch is that the state of the button is changing more than once before drawRect is called. So I just added a custom property that would only be set by methods called during touchDown and touchUpInside events. I had to dispatch threads to do this because of other operations that were holding up the main thread, causing a delay in the redrawHighlighted method.
It may be a little messy, but here's what worked for me:
// CustomButton.h
#interface CustomButton : UIButton
#property (atomic) BOOL drawHighlighted;
// CustomButton.m
#implementation CustomButton
#synthesize drawHighlighted = _drawHighlighted;
- (id)initWithFrame:(CGRect)frame
{
if ((self = [super initWithFrame:frame]))
{
_drawHighlighted = NO;
[self addTarget:self action:#selector(redrawHighlighted) forControlEvents:UIControlEventTouchDown];
[self addTarget:self action:#selector(redrawNormal) forControlEvents:UIControlEventTouchUpInside];
[self addTarget:self action:#selector(redrawNormal) forControlEvents:UIControlEventTouchDragExit];
}
return self;
}
- (void)drawRect:(CGRect)frame
{
// draw button here
}
- (void)redrawNormal
{
[NSThread detachNewThreadSelector:#selector(redrawRectForNormal) toTarget:self withObject:nil];
}
- (void)redrawHighlighted
{
[NSThread detachNewThreadSelector:#selector(redrawRectForHighlighted) toTarget:self withObject:nil];
}
- (void)redrawRectForNormal
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
_drawHighlighted = NO;
[self setNeedsDisplay];
[pool release];
}
- (void)redrawRectForHighlighted
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
_drawHighlighted = YES;
[self setNeedsDisplay];
[pool release];
}
Another cheap but effective alternative I've found is to create a drawRect: that doesn't do any highlighting, and simply alter the button subclass's alpha property when the user interacts with the button.
For example:
- (BOOL)beginTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event
{
self.alpha = 0.3f;
return [super beginTrackingWithTouch:touch withEvent:event];
}
- (void)endTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event
{
self.alpha = 1.0f;
[super endTrackingWithTouch:touch withEvent:event];
}
- (void)cancelTrackingWithEvent:(UIEvent *)event
{
self.alpha = 0.3f;
[super cancelTrackingWithEvent:event];
}
- (void)drawRect:(CGRect)rect
{
// Your drawing code here sans highlighting
}
I'd like to display an activity indicator BEFORE the work undertaken by willAnimateRotationToInterfaceOrientation:duration: begins. Most of the time in my app, this work is quickly completed and there would be no need for an activity indicator, but occasionally (first rotation, i.e. before I have cached data, when working with a large file) there can be a noticeable delay. Rather than re-architect my app to cope with this uncommon case, I'd rather just show the UIActivityIndicatorView while the app generates a cache and updates the display.
The problem is (or seems to be) that the display is not updated between the willRotateToInterfaceOrientation:duration and the willAnimateRotationToInterfaceOrientation:duration: method. So asking iOS to show UIActivityIndicator view in willRotate method doesn't actually affect the display until after the willAnimateRotation method.
The following code illustrates the issue. When run, the activity indicator appears only very briefly and AFTER the simulateHardWorkNeededToGetDisplayInShapeBeforeRotation method has completed.
Am I missing something obvious? And if not, any smart ideas as to how I could work around this issue?
Update: While suggestions about farming the heavy lifting off to another thread etc. are generally helpful, in my particular case I kind of do want to block the main thread to do my lifting. In the app, I have a tableView all of whose heights need to be recalculated. When - which is not a very common use case or I wouldn't even be considering this approach - there are very many rows, all the new heights are calculated (and then cached) during a [tableView reloadData]. If I farm the lifting off and let the rotate proceed, then after the rotate and before the lifting, my tableView hasn't been re-loaded. In the portrait to landscape case, for example, it doesn't occupy the full width. Of course, there are other workarounds, e.g. building a tableView with just a few rows prior to the rotate and then reloading the real one over that etc.
Example code to illustrate the issue:
#implementation ActivityIndicatorViewController
#synthesize activityIndicatorView = _pgActivityIndicatorView;
#synthesize label = _pgLabel;
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}
- (void) willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration;
{
NSLog(#"willRotate");
[self showActivityIndicatorView];
}
- (void) willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration;
{
NSLog(#"willAnimateRotation");
[self simulateHardWorkNeededToGetDisplayInShapeBeforeRotation];
}
- (void) didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation;
{
NSLog(#"didRotate");
[self hideActivityIndicatorView];
}
- (void) simulateHardWorkNeededToGetDisplayInShapeBeforeRotation;
{
NSLog(#"Starting simulated work");
NSDate* date = [NSDate date];
while (fabs([date timeIntervalSinceNow]) < 2.0)
{
//
}
NSLog(#"Finished simulated work");
}
- (void) showActivityIndicatorView;
{
NSLog(#"showActivity");
if (![self activityIndicatorView])
{
UIActivityIndicatorView* activityIndicatorView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
[self setActivityIndicatorView:activityIndicatorView];
[[self activityIndicatorView] setCenter:[[self view] center]];
[[self activityIndicatorView] startAnimating];
[[self view] addSubview: [self activityIndicatorView]];
}
// in shipping code, an animation with delay would be used to ensure no indicator would show in the good cases
[[self activityIndicatorView] setHidden:NO];
}
- (void) hideActivityIndicatorView;
{
NSLog(#"hideActivity");
[[self activityIndicatorView] setHidden:YES];
}
- (void) dealloc;
{
[_pgActivityIndicatorView release];
[super dealloc];
}
- (void) viewDidLoad;
{
UILabel* label = [[UILabel alloc] initWithFrame:CGRectMake(50.0, 50.0, 0.0, 0.0)];
[label setText:#"Activity Indicator and Rotate"];
[label setTextAlignment: UITextAlignmentCenter];
[label sizeToFit];
[[self view] addSubview:label];
[self setLabel:label];
[label release];
}
#end
The app doesn't update the screen to show the UIActivityIndicatorView until the main run loop regains control. When a rotation event happens, the willRotate... and willAnimateRotation... methods are called in one pass through the main run loop. So you block on the hard work method before displaying the activity indicator.
To make this work, you need to push the hard work over to another thread. I would put the call to the hard work method in the willRotate... method. That method would call back to this view controller when the work is completed so the view can be updated. I would put show the activity indicator in the willAnimateRotation... method. I wouldn't bother with a didRotateFrom... method. I recommend reading the Threaded Programming Guide.
Edit in response to a comment: You can effectively block user interaction by having the willAnimateRotation... method put a non functioning interface on screen such as a view displaying a dark overlay over and the UIActivityIndicatorView. Then when the heavy lifting is done, this overlay is removed, and the interface becomes active again. Then the drawing code will have the opportunity to properly add and animate the activity indicator.
More digging (first in Matt Neuberg's Programming iPhone 4) and then this helpful question on forcing Core Animation to run its thread from stackoverflow and I have a solution that seems to be working well. Both Neuberg and Apple issue strong caution about this approach because of the potential for unwelcome side effects. In testing so far, it seems to be OK for my particular case.
Changing the code above as follows implements the change. The key addition is [CATransaction flush], forcing the UIActivityIndicatorView to start displaying even though the run loop won't be ended until after the willAnimateRotationToInterfaceOrientation:duration method completes.
- (void) willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration;
{
NSLog(#"willRotate");
[self showActivityIndicatorView];
[CATransaction flush]; // this starts the animation right away, w/o waiting for end of the run loop
}
- (void) willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration;
{
NSLog(#"willAnimateRotation");
[self simulateHardWorkNeededToGetDisplayInShapeBeforeRotation];
[self hideActivityIndicatorView];
}
- (void) didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation;
{
NSLog(#"didRotate");
}
Try performing you work on a second thread after showing the activity view.
[self showActivityIndicatorView];
[self performSelector:#selector(simulateHardWorkNeededToGetDisplayInShapeBeforeRotation) withObject:nil afterDelay:0.01];
Either execute the heavy lifting in a background thread and post the results in the foreground thread to update the UI (UIKit is only thread safe since iOS 4.0):
[self performSelectorInBackground:#selector(simulateHardWorkNeededToGetDisplayInShapeBeforeRotation) withObject:nil]
Or you can schedule the heavy lifting method to be executed after the rotation took place:
[self performSelector:#selector(simulateHardWorkNeededToGetDisplayInShapeBeforeRotation) withObject:nil afterDelay:0.4]
But these are only hacks and the real solution is to have proper background processing if your UI needs heavy processing to get updated, may it be in portrait or landscape. NSOperation and NSOperationQueue is a good place to start.
How can I disable the touch detection within the action that running, because I don't want the character flying in the sky like a superman if the player clicking and clicking within the action, the character will never land if they keep clicking.
I found the method "isDone", is that relate to this method??
player click -> action(cannot click within the action) -> action finish -> click again.....
that's what i want~
This is the best answer to your question:
[[UIApplication sharedApplication] beginIgnoringInteractionEvents];
[[UIApplication sharedApplication] endIgnoringInteractionEvents];
Disable user interactions in your view till the action completes and then enable it again.
To disable touch
[self.view setUserInteractionEnabled:NO];
To enable touch
[self.view setUserInteractionEnabled:YES];
Please try and be a bit more concise of what you want the next time.
Swift 3.0
self.view.isUserInteractionEnabled = false
In Swift 2.2
self.view.userInteractionEnabled = false
Just gonna make a wild assumption that you're talking about the specific Action class in Cocos2D. If that's true, then you should know that every Action has an "isDone" Bool you can check to see if it's done. Let me know if that's what you're asking and I'll post an example, but there's a huge chance you could be talking about something else because your wording is so confusing ;)
You could always put a transparent UIView over top of the area you want to "disable" tap input for, have it listen for taps, and have it ignore them. Remove the UIView (or hide it) when you want input to be listened to again.
Why don't you use some kind of (simple version) boolean to remember i.e. isInAction = true and after the action finished isInAction = false...
So when someone clicks, u use something like
if (!isInAction) {
isInAction=true;
try {
doYourAction;
} catch {
...
} finally {
isInAction=false;
}
}
// The Code is some kind of pseudocode, because I haven't yet programmed for the IPhone, just to visualize what I mean.
Perhaps I didn't understand your question but is this what you're looking for?
- (BOOL)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
[Superman Fly];
self.isTouchEnabled = NO;
}
- (void)SupermanLanded{
self.isTouchEnabled = YES;
}
I am totally stumped, here's the situation:
My app uses the Core Location framework to get the current location of the user and then pings my server at TrailBehind for interesting places nearby and displays them as a list. No problems.
To conserve batteries, I turn off the GPS service after I get my data from the server. If the user moves around while using the app and wants a new list he clicks "Refresh" on the navigation controller and the CLLocation service is again activated, a new batch of data is retrieved from the server and the table is redrawn.
While the app is grabbing data from my server I load a loading screen with a spinning globe that says "Loading, please wait" and I hide the navigation bar so they don't hit "back".
So, the initial data grab from the server goes flawlessly.
The FIRST time I hit refresh all the code executes to get a new location, ping the server again for a new list of data and updates the cells. However, instead of loading the table view as it should it restores the navigation controller bar for the table view but still shows my loading view in the main window. This is only true on the device, everything works totally fine in the simulator.
The SECOND time I hit refresh the function works normally.
The THIRD time I hit refresh it fails as above.
The FOURTH time I hit refresh it works normally.
The FIFTH time I hit refresh it fails as above.
etc etc, even refreshes succeed and odd refreshes fail. I stepped over all my code line by line and everything seems to be executing normally. I actually continued stepping over the core instructions and after a huge amount of clicking "step over" I found that the table view DOES actually display on the screen at some point in CFRunLoopRunSpecific, but I then clicked "continue" and my loading view took over the screen.
I am absolutely baffled. Please help!! Many thanks in advance for your insight.
Video of the strange behavior:
Relevant Code:
RootViewControllerMethods (This is the base view for this TableView project)
- (void)viewDidLoad {
//Start the Current Location controller as soon as the program starts. The Controller calls delegate methods
//that will update the list and refresh
[MyCLController sharedInstance].delegate = self;
[[MyCLController sharedInstance].locationManager startUpdatingLocation];
lv = [[LoadingViewController alloc] initWithNibName:#"Loading" bundle:nil];
[self.navigationController pushViewController:lv animated:YES];
[super viewDidLoad];
}
- (void)updateClicked {
//When the location is successfully updated the UpdateCells method will stop the CL manager from updating, so when we want to update the location
//all we have to do is start it up again. I hope.
[[MyCLController sharedInstance].locationManager startUpdatingLocation];
[self.navigationController pushViewController:lv animated:YES];
//LV is a class object which is of type UIViewController and contains my spinning globe/loading view.
}
-(void)updateCells {
//When the Core Location controller has updated its location it calls this metod. The method sends a request for a JSON dictionary
//to trailbehind and stores the response in the class variable jsonArray. reloadData is then called which causes the table to
//re-initialize the table with the new data in jsonArray and display it on the screen.
[[MyCLController sharedInstance].locationManager stopUpdatingLocation];
if(self.navigationController.visibleViewController != self) {
self.urlString = [NSString stringWithFormat:#"http://www.trailbehind.com/iphone/nodes/%#/%#/2/10",self.lat,self.lon];
NSURL *jsonURL = [NSURL URLWithString:self.urlString];
NSString *jsonData = [[NSString alloc] initWithContentsOfURL:jsonURL];
NSLog(#"JsonData = %# \n", jsonURL);
self.jsonArray = [jsonData JSONValue];
[self.tableView reloadData];
[self.navigationController popToRootViewControllerAnimated:YES];
[jsonData release];
}
}
CLController Methods: Basically just sends all the data straight back to the RootViewController
// Called when the location is updated
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation
{
NSLog(#"New Location: %# \n", newLocation);
NSLog(#"Old Location: %# \n", oldLocation);
#synchronized(self) {
NSNumber *lat = [[[NSNumber alloc] init] autorelease];
NSNumber *lon = [[[NSNumber alloc] init] autorelease];
lat = [NSNumber numberWithFloat:newLocation.coordinate.latitude];
lon = [NSNumber numberWithFloat:newLocation.coordinate.longitude];
[self.delegate noteLat:lat];
[self.delegate noteLon:lon];
[self.delegate noteNewLocation:newLocation];
[self.delegate updateCells];
}
}
The first thought is that you may not want to send startUpdatingLocation to the CLLocationManager until after you've pushed your loading view. Often the first -locationManager:didUpdateToLocation:fromLocation: message will appear instantly with cached GPS data. This only matters if you're acting on every message and not filtering the GPS data as shown in your sample code here. However, this would not cause the situation you've described - it would cause the loading screen to get stuck.
I've experienced similarly weird behavior like this in a different situation where I was trying to pop to the root view controller when switching to a different tab and the call wasn't being made in the correct place. I believe the popToRootViewController was being called twice for me. My suspicion is that your loading view is either being pushed twice or popped twice.
I recommend implementing -viewWillAppear:, -viewDidAppear:, -viewWillDisappear: and -viewDidDisappear: with minimal logging in your LoadingViewController.
- (void)viewWillAppear:(BOOL)animated {
NSLog(#"[%# viewWillAppear:%d]", [self class], animated);
[super viewWillAppear:animated];
}
- (void)viewDidAppear:(BOOL)animated {
NSLog(#"[%# viewDidAppear:%d]", [self class], animated);
[super viewDidAppear:animated];
}
- (void)viewWillDisappear:(BOOL)animated {
NSLog(#"[%# viewWillDisappear:%d]", [self class], animated);
[super viewWillDisappear:animated];
}
- (void)viewDidDisappear:(BOOL)animated {
NSLog(#"[%# viewDidDisappear:%d]", [self class], animated);
[super viewDidDisappear:animated];
}
Then, run a test on your device to see if they are always being sent to your view controller and how often. You might add some logging to -updateClicked to reveal double-taps.
Another thought, while your #synchronized block is a good idea, it will only hold off other threads from executing those statements until the first thread exits the block. I suggest moving the -stopUpdatingLocation message to be the first statement inside that #synchronized block. That way, once you decide to act on some new GPS data you immediately tell CLLocationManager to stop sending new data.
Can you try and debug your application to see where the control goes when calling updateCells? Doesn't seem to be anything apparently wrong with the app.
Make sure that there are no memory warnings while you are in the LoadingViewController class. If there is a memory warning and your RootViewController's view is being released, then the viewDidLoad will be called again when you do a pop to RootViewController.
Keep breakpoints in viewDidLoad and updateCells. Are you sure you are not calling LoadingViewController anywhere else?
So, I never did get this to work. I observe this behavior on the device only every time I call popViewController programatically instead of allowing the default back button on the navigation controller to do the popping.
My workaround was to build a custom loading view, and flip the screen to that view every time there would be a delay due to accessing the internet. My method takes a boolean variable of yes or no - yes switches to the loading screen and no switches back to the normal view. Here's the code:
- (void)switchViewsToLoading:(BOOL)loading {
// Start the Animation Block
CGContextRef context = UIGraphicsGetCurrentContext();
[UIView beginAnimations:nil context:context];
[UIView setAnimationTransition: UIViewAnimationTransitionFlipFromLeft forView:self.tableView cache:YES];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
[UIView setAnimationDuration:.75];
// Animations
if(loading) {
if (lv == nil) { lv = [[LoadingViewController alloc] initWithNibName:#"Loading" bundle:nil]; }
[self.view addSubview:lv.view];
[self.view sendSubviewToBack:self.tableView];
self.title = #"TrailBehind";
}
else {
[lv.view removeFromSuperview];
}
// Commit Animation Block
[UIView commitAnimations];
//It looks kind of dumb to animate the nav bar buttons, so set those here
if(loading) {
self.navigationItem.rightBarButtonItem = nil;
self.navigationItem.leftBarButtonItem = nil;
self.title = #"TrailBehind";
}
else {
UIBarButtonItem *feedback = [[UIBarButtonItem alloc] initWithTitle:#"Feedback" style:UIBarButtonItemStylePlain target:self action:#selector(feedbackClicked)];
self.navigationItem.rightBarButtonItem = feedback;
UIBarButtonItem *update = [[UIBarButtonItem alloc] initWithTitle:#"Move Me" style:UIBarButtonItemStylePlain target:self action:#selector(updateClicked)];
self.navigationItem.leftBarButtonItem = update;
[feedback release];
[update release];
}
}
Looking at your original code, I suspect this block very much:
- (void)viewDidLoad {
...
lv = [[LoadingViewController alloc] initWithNibName:#"Loading" bundle:nil];
[self.navigationController pushViewController:lv animated:YES];
[super viewDidLoad];
}
viewDidLoad is called every time the NIB is loaded, which can happen multiple times, especially if you run low on memory (something that seems likely given your remark that it only happens on device). I recommend that you implement -didReciveMemoryWarning, and after calling super, at the very least print a log so you can see whether it's happening to you.
The thing that bothers me about the code above is that you're almost certainly leaking lv, meaning that there may be an increasing number of LoadingViewControllers running around. You say it's a class variable. Do you really mean it's an instance variable? ivars should always use accessors (self.lv or [self lv] rather than lv). Do not directly assign to them; you will almost always do it wrong (as you are likely dong here).
I came across this while searching for the exact same issue, so while I'm sure you've already solved your problem by now, I figured I'd post my solution in case someone else runs across it...
This error seems to be caused when you assign two IBActions to the same UIButton in interface builder. It turned out that the button I used to push the view controller onto the stack was assigned to two IBActions, and each one was pushing a different controller onto the navigationController's stack (although you'll only end up seeing one of them - perhaps the last one to be called). So anyway, pressing the back button on the topmost view doesn't really dismiss it (or maybe it's dismissing the 2nd, unseen controller), and you have to press twice to get back.
Anyway, check your buttons and be sure they're only assigned to a single IBAction. That fixed it for me.