I have a strange issue .
I am currently working on a mail app and it used to crash randomly without and error or logs in my console . I checked my Crash Log it showed me Low Memory warning with jettisoned written next to my App.
So I suspect it's an memory issue and went back to trace my memory usage of my application.
I used allocation instrument to detect the overall usage and my application crashed when it's heap size was just 4.59 MB.
Instruments point towards a function where I am using MBProgressHUD indicator.
The culprit is this one line :
[appDelegate showHUDActivityIndicatorOnView:self.parentViewController.view whileExecuting:#selector(refreshInBackground) onTarget:self withObject:nil withText:#"Loading"];
If I replace this with
[self refreshInBackground] everything works fine no issues ..
Here is the code :
-(void) showHUDActivityIndicatorOnView:(UIView*)view whileExecuting:(SEL)method
onTarget:(id)target withObject:(id)object withText:(NSString*)label{
self.HUD = [[MBProgressHUD alloc] initWithView:view] ;
self.navigationController.navigationItem.hidesBackButton = YES;
[view addSubview:self.HUD];
self.HUD.delegate = nil;
self.HUD.labelText = label;
[self.HUD showWhileExecuting:method onTarget:target withObject:object animated:YES];
}
self.HUD is a property which is being retained.
With a slight modification is showWhileExecuting method as follows :
- (void)showWhileExecuting:(SEL)method onTarget:(id)target withObject:(id)object animated:(BOOL)animated {
MyAppdelegate *appDelegate = (MyAppdelegate *)[UIApplication sharedApplication].delegate;
if(!appDelegate.isRequestActive)
{
methodForExecution = method;
targetForExecution = [target retain];
objectForExecution = [object retain];
// Launch execution in new thread
taskInProgress = YES;
[NSThread detachNewThreadSelector:#selector(launchExecution) toTarget:self withObject:nil];
// Show HUD view
[self show:animated];
}
else {
[self done];
}
}
currently I have removed this from my app and it works fine now and it does not crashes even with the usage of 20 - 30 MB heap Memory .
I am not looking for an specific answer or solution here . What I am looking for ways to debug / techniques to debug the issue so that I can get to know what caused my app to crash .
Is it memory overflow . If that's the case then how can I use 20-30 MB right now.
If it's not an memory issue why does my crash reporter shows jettisoned next to my App name .
the culprit line ([appDelegate showHUDActivityIndicatorOnView:self.parentViewController.view whileExecuting:#selector(refreshInBackground) onTarget:self withObject:nil withText:#"Loading"])
Every time when I call this function some memory increases , because of some elements being cached . But when memory reached 4.5 MB ...this line cause it to crash
How do I get to the root cause of this issue . How do I figure out why iOS is killing my app the reason for jettisoned written next to my app
Any help or suggestions would be really appreciated .
Ok. The problem is I was adding the HUD progress bar on my view using
[view addSubview:self.HUD];
I forgot to remove it from the super view in its delegate method:
- (void)hudWasHidden:(MBProgressHUD *)hud
{
// Remove HUD from screen when the HUD was hidded
[HUD removeFromSuperview]; // app crashes at 4.59 MB if you comment this
[HUD release];
HUD = nil;
}
Because of this several views were added every time on one UIView ... I guess there is an upper limit for the number of child subviews on top of each UIView .... apple should mention this in their documentation ...
If you're not using ARC, you have for sure a leak every time you assign the property:
self.HUD = [[MBProgressHUD alloc] initWithView:view] ;
Change your code in this way:
MBProgressHUD *progressHUD = [[MBProgressHUD alloc] initWithView:view] ;
self.HUD = progressHUD;
[progressHUD release];
I can't make the static analyzer 'like' this code, but at the same time I cannot autorelease the object that gets stored into controller, so it is useless for the caller. With these 2 static methods I've tried to make it easier to display an activity controller over any view (without blocking tabs).
PZActivityOverlayController *view = [PZActivityOverlayController displayOverView:self.view];
// Later on, when complete
[PZActivityOverlayController remove:view];
Original code:
+ (PZActivityOverlayController *)displayOverView:(UIView *)aView {
PZActivityOverlayController *controller = [[PZActivityOverlayController alloc] initWithFrame:aView.superview.bounds labelText:#"Loading"];
[controller viewWillAppear:YES];
[aView.superview insertSubview:controller.view aboveSubview:aView];
return controller; // Potential leak of object stored into controller
}
+ (void)remove:(PZActivityOverlayController *)display {
[display viewWillDisappear:YES];
[display.view removeFromSuperview];
[display release]; // However it won't leak because it gets released here
}
Perhaps I have the chain of responsibility wrong here, but it's only for convenience. The alternative would be writing what's in the body of these methods everywhere (which violates DRY too much for me).
There's a rule (say, convention) - nonautoreleased objects are returned by methods alloc&init..., new, retain, copy. All the rest methods are HAVE TO return autoreleased object.
In your case I'd rewrite the code above:
....
return [controller autorelease];
}
+ (void)remove:(PZActivityOverlayController *)display {
[display viewWillDisappear:YES];
[display.view removeFromSuperview];
}
...
PZActivityOverlayController *view = [[PZActivityOverlayController displayOverView:self.view] retain];
// Later on, when complete
[PZActivityOverlayController remove:view];
[view release];
Hi
I am adding a "post comment section in my iPhone APP"
rest all things are working fine but when I tap on "postController textView" a keyboard is suppose to appear from the bottom but it is not appearing However the cursor is displaying and the text that I am passing using postController.textView.text = #"" is also displaying.
Please suggest the areas to be looked for fixing this bug.
-(void)showCommentView
{
TTPostController *postController = [[TTPostController alloc] init];
// self must implement the TTPostControllerDelegate protocol
postController.delegate = self;
self.popupViewController = postController;
// assuming self to be the current UIViewController
postController.superController = self;
postController.textView.text=#"temporary text";
[postController showInView:self.view animated:YES];
[postController release];
}
above is the code that is giving call to the Three20 PostController
below is the calling method which is unchanged...
-(IBAction)postComment:(id)sender
{
[UserManager instance]authenticateUserAndProceed:self withSelector:#selector(showCommentView)];
}
-(void)showCommentView
{
TTPostController *postController = [[TTPostController alloc] init];
// self must implement the TTPostControllerDelegate protocol
postController.delegate = self;
self.popupViewController = postController;
// assuming self to be the current UIViewController
postController.superController = self;
postController.textView.text=#"temporary text";
[postController showInView:self.view animated:YES];
[postController release];
}
changed method
-(void)authenticateUserAndProceed:(id)parent withSelector:(SEL)selector
{
theParentViewController = parent;
self.theFunctionToCall = selector;
if(userid == nil)
{
GetUserInfoViewController *guivc = [[GetUserInfoViewController alloc] init];
[parent presentModalViewController:guivc animated:YES];
guivc.delegate = self;
[guivc release];
}
else {
//////////////////// below line was replaced///////////
// 2. [theParentViewController performSelector:selector];
// with below code
UIAlertView *alert =[[UIAlertView alloc]initWith Title........
[alert show];
}
}
PROBLEM SUMMARY:
as soon as the user registered, he was not able to the kyboard for the TTPostController
CHANGE SUMMARY:
As soon as the user is registered the call to
[theParentViewController performSelector:selector];
is not sent directly but the call goes to ann alertview which inter calls it.
EFETCS SUMMARY:
the user will see a "you are registered successfully" (kind of) alertview.
tapping OK on which, he will be sent to TTPostController. (this time the keyboard is appearing)
I kept the line# 2 in the AlertViewDelegate method.
I was amazed o see it working just by not calling the line 2 directly.
this worked for me.
I welcome any new and better idea to implement the same
I have a problem with removing a subview, or more precisely with checking if it is still there after having deleted it.
My app first adds a subview to self.view.
[self.view addSubview:tabsClippedView];
Then it adds another subview to this subview (to which it adds several buttons as subviews, but I guess this is unimportant in this context):
[tabsClippedView addSubview:tabsView];
Finally, I have a method which allows the tabsView to be deleted and then created again. I need to do this so as to update the number of buttons in that tabsView (as the user can delete buttons). The method looks basically like this:
[self.tabsView removeFromSuperview];
After that I call a method called showTabs (which I already called in the very beginning of the app in order to add the subViews). This is where it all becomes problematic and where my app crashes (I get no error in the debug console, so I don't really know what the issue is...):
if ([tabsClippedView isDescendantOfView:self.view]) {
NSLog(#"There is already a tabsClippedView.");
} else {
NSLog(#"There is no tabsClippedView. I'll add one...");
[self initTabsClippedView];
}
This is where the app crashes: when trying to assess if tabsView isDescendantOfView (I don't get any of the following logs):
if ([tabsView isDescendantOfView:tabsClippedView]) {
NSLog(#"There is already a tabsView");
} else {
NSLog(#"There is no tabsView for the buttons. I'll add one including buttons.");
[self initTabs];
}
I'd be grateful for any suggestions where the problem could be.
EDIT:
These are the methods to set up my views:
-(void) initTabsClippedView { // sets up tabsClippedView
NSLog(#"initTabsClippedView method started...");
CGRect tabsClippedFrame = CGRectMake(258,30,70,81*6);
tabsClippedView = [[[UIView alloc] initWithFrame:tabsClippedFrame] autorelease];
tabsClippedView.clipsToBounds = true;
[self.view addSubview:tabsClippedView];
NSLog(#"initTabsClippedView method ended.");
}
-(void) initTabs {
NSLog(#"initTabs started. Adding buttons to tabsClippedView...");
CGRect tabsFrame = CGRectMake(-30,0,50,480);
tabsView = [[[UIView alloc] initWithFrame:tabsFrame] autorelease];
[tabsClippedView addSubview:tabsView];
// sets up buttons in tabsClippedView
And this is where I delete the tabsClippedView (triggered by a button found in tabsClippedView):
-(void)tabDelete:(id)sender
{
UIButton *button = (UIButton *)sender;
[UIView animateWithDuration:0.75
delay:0
options:UIViewAnimationOptionCurveEaseIn
animations:^{
button.transform = CGAffineTransformMakeTranslation(-30, 0);
}
completion:^(BOOL finished){
[UIView animateWithDuration:0
delay:0
options:UIViewAnimationOptionCurveEaseIn
animations:^{
[self.tabsView removeFromSuperview];
//...
}
completion:^(BOOL finished){
NSLog(#"tabsView removed from Superview. Objects Deleted.");
[self showTabs];
NSLog(#"TabDelete finished. Button removed and tabsView updated accordingly.");
}
];
}];
And this is the showTabs method which was already called when I started the app:
-(void)showTabs {
NSLog(#"showTabs started...");
currentView = #"Tabs";
if ([tabsClippedView isDescendantOfView:self.view]) {
NSLog(#"There is already a tabsClippedView.");
} else {
NSLog(#"There is no tabsClippedView. I'll add one...");
[self initTabsClippedView];
}
if ([tabsView isDescendantOfView:tabsClippedView]) {
NSLog(#"There is already a tabsView");
} else {
NSLog(#"There is no tabsView for the buttons. I'll add one including buttons.");
[self initTabs];
}
Is it possible that you are getting EXC_BAD_ACCESS? Is it possible that the app is crashing because tabsView is deallocated when you send isDescendantOfView: to it. If you run with breakpoints enabled it should tell you the reason for the crash. If it is an EXC_BAD_ACCESS problem you should try NSZombie.
To activate NSZombie do the following:
Get info of the executable.
Go to the arguments tab.
In the "Variables to be set in the environment:" section add:
Name: NSZombieEnabled
Value: YES
Then run your app as usual and when it crashes it should tell you which deallocated object received what message.
EDIT: Just saw your edit. I think I nailed it. You're autoreleasing the views when you create them, so when they are removed from their superviews they are no longer retained and thus deallocated. You're app crashes because you're trying to run methods on deallocated views.
EDIT 2: Thought I should tell you that there is a better solution than the one posted by Praveen S.
Change your code as follows:
[tabsClippedView release];
tabsClippedView = [[UIView alloc] initWithFrame:tabsClippedFrame];
and
[tabsView release];
tabsView = [[UIView alloc] initWithFrame:tabsFrame];
The above code does the same thing as the code posted by Praveen S, but without the autorelease. An autorelease is more expensive than a regular release and should only be used when needed and in this case it isn't.
Rather than releasing before you allocate a new view you probably want to release the view when you're done with it:
[tabsView removeFromSuperview];
[tabsView release];
tabsView = nil;
or simply
[tabsView removeFromSuperview];
self.tabsView = nil;
and then instead of:
if ([tabsView isDescendantOfView:tabsClippedView]) ...
you can use:
if (tabsView) ...
As you might have noticed, there really is no need for you to retain the view. You could just as well do the following:
tabsView = [[UIView alloc] initWithFrame:tabsFrame];
[tabsClippedView addSubview:tabsView]; // This retains tabsView
[tabsView release];
and then to remove the view you would use:
[tabsView removeFromSuperview]; // This will release the tabsView
tabsView = nil;
Also remember to set the views to nil in viewDidUnload.
EDIT 3: Why self made such a difference:
What you need to understand is how properties and reference counting works. There are books and such you could read about it. I'm sure Google can provide you with some good references as well.
The difference between
self.tabsView = [[UIView alloc] initWithFrame:frame];
and
tabsView = [[UIView alloc] initWithFrame:frame];
is that self.tabsView is accessing the properties setter, while tabsView is accessing the instance variable directly.
A nonatomic, retain property's implementation looks something like the following:
- (void)setTabsView:(UIView *)view
{
if (view != tabsView) {
[tabsView release];
tabsView = [view retain];
}
}
So the property is taking care of the memory management for you. In my solution I take care of the memory management myself and thus I don't need the property to do it for me, so I don't use it.
I hope this explains why self made such a difference.
Change your code as follows:
self.tabsClippedView = [[[UIView alloc] initWithFrame:tabsClippedFrame] autorelease];
and
self.tabsView = [[[UIView alloc] initWithFrame:tabsFrame] autorelease];
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.