I am trying to learn how to drop pins on a map in iOS 6. I have a code which compiles and runs but which obviously leaks memory -- but when I release (or autoRelease) the mapData object my app crashes. The error is
An instance 0x1b7ac0 of class AddressAnnotation was deallocated while key value observers were still registered with it. Observation info was leaked, and may even become mistakenly attached to some other object. Set a breakpoint on NSKVODeallocateBreak to stop here in the debugger.
There is an earlier post on just this error, also with respect to MapKit:
Setting breakpoint at NSKVODeallocateBreak
But it does not help me:
First, I don't really understand the answer, but also it seems the answer is not relevant to my problem because I am not setting an observer in any way (that I know of, that is!) For example, nowhere in my code do I have the lines
[addressAnnotation addObserver:self forKeyPath:kSelectedAnnotationObserverKeyPath options:NSKeyValueObservingOptionNew context:#"selectedOrDeselected"];
or anything else remotely similar, which were suggested to be the problem.
Having said that, I should also say I do not really understand the concept of the observer -- I have of course created a custom class MapData, which is an NSObject <MKAnnotation> and I suppose that this could also be a source of the problem. But I am basically plumb stupefied.
I have tried to set the suggested symbolic break point but it is not helpful to me: I see I have a BAD ACCESS condition but that is all I really understand!
The code I have written is this:
- (void) showRecordsOnMap
{
NSMutableArray *projectMapAnnotationsArray;
projectMapAnnotationsArray = [[NSMutableArray alloc] init];
int i = 0;
for (i = 0; i < [currentProject.recordArray count]; i++)
{
Record *record = [[[Record alloc] init]autorelease];
record = [currentProject.recordArray objectAtIndex:i];
CLLocationCoordinate2D newCoordinate;
newCoordinate.latitude = record.latitude;
newCoordinate.longitude = record.longitude;
int tag = 0;
NSString *title;
title = [[[NSString alloc] init] autorelease];
title = [NSString stringWithFormat:#"Record %d",record.record_ID];
NSString *subtitle;
subtitle = [[[NSString alloc] init] autorelease];
subtitle = [NSString stringWithFormat:#"Record %d",record.record_ID];
MapData *mapData =[[MapData alloc] initWithCoordinate:newCoordinate withTag:tag withTitle:title withSubtitle:title];
[projectMapAnnotationsArray addObject:mapData];
//[mapData release];
}
[projectMap addAnnotations:projectMapAnnotationsArray];
[projectMapAnnotationsArray release];
}
and then the next needed bit
- (MKAnnotationView *) mapView:(MKMapView *)mapView
viewForAnnotation:(MapData *)annotation
{
static NSString *record = #"record";
//the result of the call is being cast (MKPinAnnotationView *) to the correct
//view class or else the compiler complains
MKPinAnnotationView *annotationView = (MKPinAnnotationView *)[projectMap
dequeueReusableAnnotationViewWithIdentifier:record];
if(annotationView == nil)
{
annotationView = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:record] autorelease];
}
//if((annotation).tag == 2) annotationView.pinColor = MKPinAnnotationColorRed;
//else annotationView.pinColor = MKPinAnnotationColorGreen;
annotationView.pinColor = MKPinAnnotationColorGreen;
//pin drops when it first appears
annotationView.animatesDrop=TRUE;
//tapping the pin produces a gray box which shows title and subtitle
annotationView.canShowCallout = YES;
return annotationView;
}
This code runs, so long as the mapData object is not released. But clearly I need to release it. As another clue, if I uncomment
// if((annotation).tag == 2) annotationView.pinColor = MKPinAnnotationColorRed;
// else annotationView.pinColor = MKPinAnnotationColorGreen;
I get another error:
[MKUserLocation tag]: unrecognized selector sent to instance 0x9fcb010
2013-05-22 23:05:13.726 Geo360[1175:c07] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[MKUserLocation tag]: unrecognized selector sent to instance 0x9fcb010'
but it seems to me that this second error is a simpler stupidity on my part that I at least know how to go about finding. But the error "class AddressAnnotation" has me totally lost. Any help is greatly appreciated!
Edit:
Hi All -- Thank you for taking the time to help. I am still confused. Attached is the code for the MapData object as suggested by AnnaKarenina. Verbumdei suggested I put the array in ViewDidLoad method as a strong property -- I had played with that but I also want to be able to refresh the map pins with an array that may have more data or fewer data, so it seemed to me I needed to make the array anew each time. Perhaps not? AnnaKarenina suggested there may be a release problem in MapData and now that I look at it I am a bit suspicious that I am not releasing tag -- but on the other hand, doing so generates a warning!
Thank you again for helping... still not solved.
MapData.h:
#import <Foundation/Foundation.h>
#import <CoreLocation/CoreLocation.h>
#import <MapKit/MapKit.h>
#interface MapData : NSObject <MKAnnotation>
{
NSString *_title;
NSString *subtitle;
NSUInteger tag;
CLLocationCoordinate2D _coordinate;
}
#property (nonatomic, readonly) CLLocationCoordinate2D coordinate;
#property (nonatomic, copy) NSString *title;
#property (nonatomic, copy) NSString *subtitle;
#property(nonatomic) NSUInteger tag;
// Getters and setters
- (id)initWithCoordinate:(CLLocationCoordinate2D)c withTag:(NSUInteger)t withTitle:(NSString *)tl withSubtitle:(NSString *)s;
#end
and MapData.m:
#import "MapData.h"
#implementation MapData
#synthesize coordinate;
#synthesize title;
#synthesize subtitle;
#synthesize tag;
-(id)initWithCoordinate:(CLLocationCoordinate2D)c withTag:(NSUInteger)t withTitle:(NSString *)tl withSubtitle: (NSString *)s
{
if(self = [super init])
{
coordinate = c;
tag = t;
title = tl;
subtitle = s;
}
return self;
}
- (void) dealloc
{
[title release];
[subtitle release];
[super dealloc];
}
#end
Regarding the crash with EXC_BAD_ACCESS, this is most likely due to this code in the MapData initWithCoordinate method:
title = tl;
subtitle = s;
By initializing the instance variables this way, the strings are not retained by the MapData object. When you call [mapData release], the strings are deallocated and then later when the map view tries to access the annotation's title and subtitle, it crashes.
Change the initialization to:
title = [tl copy];
subtitle = [s copy];
and un-comment the [mapData release];
Regarding the "deallocated while key value observers were still registered..." warning message, this is possibly due to invalid coordinates being used for an annotation (see Warning in Custom Map Annotations iPhone). For each annotation, make sure the latitude is from -90 to 90 and the longitude is from -180 to 180.
Regarding the "[MKUserLocation tag]: unrecognized selector" crash, this is unrelated to both of the above issues. This error happens because the viewForAnnotation delegate method is called by the map view for all annotations -- not just the ones you add. This means it is also called for the user location blue dot that the map view itself creates. That user location annotation is of type MKUserLocation while your custom annotation is of type MapData. When the map view calls viewForAnnotation for the user location, that code crashes because the MKUserLocation class does not have a tag property.
The simplest way to handle this is at the top of the viewForAnnotation method, check if the annotation is of type MKUserLocation and return nil for the view (which tells the map view to display the default view which is a blue dot for the user location).
Also, do not change the type declaration of the annotation parameter in the viewForAnnotation method to your custom type (even though it "works"). As explained, the method is called for MKUserLocation as well as your custom class (or classes). Keep it the generic type id<MKAnnotation> which means "an object that implements the MKAnnotation protocol". Then, to access properties of your custom class, cast annotation to your custom class type.
So the top of the viewForAnnotation method should be like this:
- (MKAnnotationView *)mapView:(MKMapView *)mapView
viewForAnnotation:(id<MKAnnotation>)annotation
{
if ([annotation isKindOfClass:[MKUserLocation class]])
return nil; //show standard blue dot view for user location
Then change these lines:
if((annotation).tag == 2) annotationView.pinColor = MKPinAnnotationColorRed;
else annotationView.pinColor = MKPinAnnotationColorGreen;
to this:
if ([annotation isKindOfClass:[MapData class]])
{
MapData *mapData = (MapData *)annotation;
if (mapData.tag == 2)
annotationView.pinColor = MKPinAnnotationColorRed;
else
annotationView.pinColor = MKPinAnnotationColorGreen;
}
There are also a few other things (not related to the crash or errors):
This pattern is wrong:
Record *record = [[[Record alloc] init]autorelease];
record = [currentProject.recordArray objectAtIndex:i];
The alloc+init+autorelease is pointless because the variable is then immediately reassigned to another object which has already been allocated. Instead, just declare and assign the local variable:
Record *record = [currentProject.recordArray objectAtIndex:i];
The same applies to how title and subtitle are set in the same method.
In showRecordsOnMap, tag is always 0. Perhaps your code isn't finished yet but be sure to set a different value for each annotation. If you leave the tag as zero for all annotations, the code you put in viewForAnnotation to set the pin color based on tag will not work as expected.
In this line you are passing title for both the title and subtitle parameters:
MapData *mapData =[[MapData alloc] initWithCoordinate:newCoordinate
withTag:tag withTitle:title withSubtitle:title];
In viewForAnnotation, after dequeuing an existing annotation view, you should update the re-used view's annotation property to the current one (add the else part):
if (annotationView == nil)
{
annotationView = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:record] autorelease];
}
else
{
//We're re-using a view from another annotation
//that's no longer on screen.
//Update the view's annotation to the current one...
annotationView.annotation = annotation;
}
While the annotations are shown in the map, you must not release the MapData objects. If you want to release the MapData objects, you need to remove the annotations first from the map.
I would suggest you make the projectMapAnnotationsArray as a strong property of the view controller. Allocate it in the viewDidLoad method. Then you can just release it in the dealloc method of the view controller.
Inside the showRecordsOnMap method, you can just add the objects to the projectMapAnnotationsArray without releasing the array itself.
Related
I'm doing my first steps in finding memory leaks in xCode 4.5 and using the Leaks instrument. I found a couple of issues and seemed to fix them, but this one eludes me.
Here is the code:
RUBEImageInfo* imgInfo = [[[RUBEImageInfo alloc] init] autorelease];
NSString *nm = [NSString stringWithUTF8String:img->name.c_str()];
imgInfo->name = nm;
[imgInfo->name retain]; // I'm using it outside of this method
Leaks reports a leak in the second line, with the percentage next to the "i" at %100.
So I tried two things:
One, I marked nm with autohrleas like this:
NSString *nm = [[NSString stringWithUTF8String:img->name.c_str()] autorelease];
Two, I also tried calling release on nm after it's assignment to imgInfo->name so the code looks like this:
imgInfo->name = nm;
[imgInfo->name retain];
[nm release];
But in both cases the app crashes with BAD_ACCESS when I run it, and call [imgInfo->name UTF8String].
What am I missing?
EDIT following Rob's answer:
This is the RUBEImageInfo class:
#import "cocos2d.h"
#interface RUBEImageInfo : NSObject {
#public CCSprite* sprite; // the image
#public NSString* name; // the file the image was loaded from
#public class b2Body* body; // the body this image is attached to (can be NULL)
#public float scale; // a scale of 1 means the image is 1 physics unit high
#public float angle; // 'local angle' - relative to the angle of the body
#public CGPoint center; // 'local center' - relative to the position of the body
#public float opacity; // 0 - 1
#public bool flip; // horizontal flip
#public int colorTint[4]; // 0 - 255 RGBA values
}
#end
And the .m:
#import "RUBEImageInfo.h"
#implementation RUBEImageInfo
// Nothing much to see here. Just make sure the body starts as NULL.
-(id)init
{
if( (self=[super init])) {
body = NULL;
}
return self;
}
-(void) dealloc {
[name release];
[super dealloc];
}
#end
A couple of reactions:
Instruments identified where the leaked object was allocated, but in this case, this code might not be the source of the leak. You should:
ensure you release the name in the dealloc method of RUBEImageInfo; and
also, if you're setting name a second time, make sure you release the previous name object before you set it to a new object.
Your life will be much easier if you use declared properties rather than dereferencing class instance variables. For example, if name was declared as:
#property (nonatomic, copy) NSString *name; // you could use `retain`, too, but `copy` is safer when dealing with strings
Then you would set the name property as so:
RUBEImageInfo* imgInfo = [[[RUBEImageInfo alloc] init] autorelease];
NSString *nm = [NSString stringWithUTF8String:img->name.c_str()];
imgInfo.name = nm;
// this is no longer needed as the `name` setter will take care of memory semantics
// [imgInfo->name retain]; // I'm using it outside of this method
By using the setter accessor method (i.e. the "dot syntax" of imgInfo.name), it will take care of a lot of routine memory semantics of releasing any previous object that name may have referenced, and it will do the necessary copy or retain. Obviously, the RUBEImageInfo method dealloc still needs to release name, but at least it simplifies the memory semantics of the name property of RUBEImageInfo objects.
Since you are using manual reference counting, I'd encourage you to investigate the "static analyzer" (invoked by selecting "Analyze" from Xcode's "Product" menu). The Leaks tool in Instruments will tell you what leaked, but it doesn't tell you where the leak happened; it has no way of knowing; it can only show you where the leaked object was allocated and you'll have to hunt down the logic error yourself. The static analyzer can sometimes point out errors that lead to leaks, but more importantly, show you where the leak was caused, rather than just where the leaked object was originally instantiated. You should have a clean bill of health from the static analyzer before you even bother running Instruments.
Looking at your code sample, if you're not going to use declared properties (not sure why you wouldn't, as it makes life easier, but to each his own), I'd suggest making sure you initialize all of your objects in init and release all of them in dealloc:
#implementation RUBEImageInfo
-(id)init
{
if ((self=[super init])) {
body = NULL;
name = nil;
sprite = nil;
// I might initialize other class instance variables here, too, but that's up to you
}
return self;
}
-(void) dealloc {
[name release];
// shouldn't you release `body` and `sprite`, too?
[super dealloc];
}
#end
Then your code that sets the name instance variable would make sure to release the previous object before setting the new object. Thus the initial instantiation might look like:
RUBEImageInfo* imgInfo = [[[RUBEImageInfo alloc] init] autorelease];
NSString *nm = [NSString stringWithUTF8String:img->name.c_str()];
imgInfo->name = [nm retain]; // retain the new object
But if you update it later, you should:
NSString *nm = [NSString stringWithUTF8String:someNewImg->name.c_str()];
[imageInfo->name release]; // release the old one
imgInfo->name = [nm retain]; // retain the new object
NSLog is returning the output 'Null" instead of a string that I would have expected. I suspect that this is a problem with private instance variables and such, but since I am not familiar with Object-oriented programming I cannot determine the cause.
//The viewDidLoad method in MainGameDisplay.m:
- (void)viewDidLoad
{
[super viewDidLoad];
Engine *engine = [[Engine alloc] init];
[engine setPlayerName: viewController];
}
The string is entered by a UITextField, the property being
//ViewController.h
#property (strong, nonatomic) IBOutlet UITextField *PlayerNameTextView;
The method works fine and returns the correct string if [engine setPlayerName: self] is placed into ViewController, but anywhere outside the location that *PlayerNameTextView is causes this problem.
//Engine.m
#implementation Engine
{
ViewController *firstPage;
}
NSString *Player;
-(void) setPlayerName: (ViewController *) name
{
Player = [[name PlayerNameTextView] text];
NSLog(#"%#", Player);
}
NSLog return type is void as you can see in it's documentation. There is no reason to expect any return value for a call to it, since it does not return anything.
Make sure that 'name' is properly initialized. Try putting an assert(name != nil) right before the NSLog. Or better yet, set a breakpoint at the NSLog and inspect the variables.
Another suggestion: Why not make the method -(void) setPlayerName:(NSString*)name? This is more straightforward than passing around pointers to view controllers, and would be easier to debug.
After many hours wasted, I officially turn to the experts for help!
My problem lies with using a NSMutableArray as an instance variable, and trying to both add objects and return the array in a method in my class. I am obviously doing something fundamentally wrong and would be grateful for help...I have already tried all the suggestions from other similar questions on stackoverflow, read apples documentation, and basically all combinations of trial and error coding I can think of. The mutable array just alway returns (null). I've even tried creating properties for them, but still the array returns (null) and then I also am running into memory management problems due to the retain while setting the property, and the init in the init method for the class.
Here is what I am trying to do:
1) Loop through a series of UISwitches and if they are 'switched on', add a string to the NSMutableArray
2) Assign this mutable array to another array in another method
Any help much appreciated,
Andy
And for some code...
fruitsViewController.h
#import <UIKit/UIKit.h>
#interface fruitsViewController : UIViewController
{
NSMutableArray *fruitsArr;
UISwitch *appleSwitch;
UISwitch *orangeSwitch;
}
#property (nonatomic,retain) NSMutableArray *fruitsArr; // ADDED ON EDIT
#property (nonatomic,retain) IBOutlet UISwitch *appleSwitch;
#property (nonatomic,retain) IBOutlet UISwitch *orangeSwitch;
- (IBAction)submitButtonPressed:(id)sender;
#end
fruitsViewController.m
#import "fruitsViewController.h"
#implementation fruitsViewController
#synthesize fruitsArr; // ADDED ON EDIT
#synthesize appleSwitch, orangeSwitch;
/* COMMENTED OUT ON EDIT
-(id)init
{
if (self = [super init]) {
// Allocate memory and initialize the fruits mutable array
fruitsArr = [[NSMutableArray alloc] init];
}
return self;
}
*/
// VIEW DID LOAD ADDED ON EDIT
- (void)viewDidLoad
{
self.fruitsArr = [[NSMutableArray alloc] init];
}
- (void)viewDidUnload
{
self.fruitsArr = nil;
self.appleSwitch = nil;
self.orangeSwitch = nil;
}
- (void)dealloc
{
[fruitsArr release];
[appleSwitch release];
[orangeSwitch release];
[super dealloc];
}
- (IBAction)submitButtonPressed:(id)sender
{
if ([self.appleSwitch isOn]) {
[self.fruitsArr addObject:#"Apple"; // 'self.' ADDED ON EDIT
}
if ([self.orangeSwitch isOn]) {
[self.fruitsArr addObject:#"Orange"; // 'self.' ADDED ON EDIT
}
NSLog(#"%#",self.fruitsArr); // Why is this returning (null) even if the switches are on?!
[fruitsArr addObject:#"Hello World";
NSLog(#"%#",self.fruitsArr); // Even trying to add an object outside the if statement returns (null)
}
#end
It seems like your init function is never called. If you're initializing this view controller from a NIB, you need to use initWithCoder. If not, just declare your fruitsArr in viewDidLoad.
Use view did load instead of init...
- (void)viewDidLoad
{
fruitsArr = [[NSMutableArray alloc] init];
}
Change that init for viewDidLoad and see what happens
Is your init method ever being called (in complicationsViewController). Add a NSLog to check this, you might be calling initWithNib: maybe.
At viewDidUnload you should remove self.fruitsArr = nil;, or, if you want to keep it, then initialize the fruitsArr in viewDidLoad (and remove it from init).
because fruitsArr don't be init.
you should do this first:
fruitsArr = [[NSMutableArray alloc] init];
so, I think you don't run - (id)init before you use fruitsArr.
UIView *view; //1
UISegmentedControl *scopeBar; //2
NSMutableArray *array; //3
#property (nonatomic, retain) IBOutlet UIView *view;
#property (nonatomic, retain) UISegmentedControl *scopeBar;
#property (nonatomic, retain) NSMutableArray *array;
.m
#synthesize view, scopeBar, array;
for (id subView in [view subviews]) {
if ([subView isMemberOfClass:[UISegmentedControl class]]) {
scopeBar = (UISegmentedControl *)subView;
}
}
array = [[NSMutableArray alloc] init];
- (void)dealloc {
}
I think that only the third of the variables has to be released in the dealloc method.
Is that right?
Yes, (array needs to be released) because you alloc it. So, it's programmer's responsibility to release it. So -
- (void)dealloc {
[ array release ] ;
// Any other resources alloc, init, new should be released
}
For more info on what to release, Memory management - ObjectiveC
And I think you will find good suggestions in this question about your query
Why should we release?
Contrary to some of the answers, you have to release your outlet (view) as well, and not only in the dealloc but also in the viewDidUnload, the easiest way is to set it to nil :
self.view = nil;
Also note that if you don't access your properties but your instance variables (i.e. without self. prefix) your retain attribute won't help you and you are not retaining the object. That means that as soon as scopeBar would be removed out of the subViews of the view, it will be released and you end up accessing a zombie.
As a rule of thumb, it's best to use the properties accessor everywhere except in the init methods so that you don't have to deal with the memory management explicitly. Setting them to nil in the dealloc and viewDidUnload in case of outlets should be enough then.
Also, don't do what Jenifer suggested and once you've called a release on a variable, don't set the property to nil, that would overrelease it.
I think that only the third of the variables has to be released in the dealloc method. Is that right?
// no. your dealloc should look like this:
- (void)dealloc {
// note: *not* using accessors in dealloc
[view release], view = nil;
[scopeBar release], scopeBar = nil;
[array release], array = nil;
[super dealloc];
}
// your assignment of `scopeBar` should look like this:
...
self.scopeBar = (UISegmentedControl *)subView;
...
// you want to retain the view, as advertised.
// consider avoiding an ivar if you can easily access it.
// your assignment of `view` should look like this:
...
self.view = theView;
...
// you want to retain the view, as advertised.
// consider avoiding an ivar if you can easily access it.
// your assignment of `array` should look like this in your initializer:
// note: *not* using accessors in initializer
...
// identical to `array = [[NSMutableArray alloc] init];`
array = [NSMutableArray new];
...
// and the assignment of `array` should look like this in other areas:
...
self.array = [NSMutableArray array];
...
// you're likely to be best suited to declare your array as
// follows (assuming you really need a mutable array):
...
NSMutableArray *array; // << the declaration of the ivar
...
...
// the declaration of the public accessors.
// note the array is copied, and passed/returned as NSArray
#property (nonatomic, copy) NSArray *array;
...
// finally, the implementation manual of the properties:
- (NSArray *)array {
// copy+autorelease is optional, but a good safety measure
return [[array copy] autorelease];
}
- (void)setArray:(NSArray *)arg {
NSMutableArray * cp = [arg mutableCopy];
// lock? notify?
NSMutableArray * prev = array;
array = cp;
[prev release], prev = nil;
// unlock? notify? update?
}
other answers assume that dangling pointers (e.g., you still hold a pointer to view, although the view may have changed behind your back) are allowable.
they should not be allowed in real programs. they are extremely dangerous, and it can very difficult to reproduce errors they cause. therefore, you must ensure you own a reference to the pointers you maintain/hold.
you should also use the accessors in the public interface for the subclasser's sake - in case they override them. if you don't want to allow/support that, consider simply using a private variable.
As i think you should release and set them nil because you have made them properties so do this:-
in your dealloc
[array release];
self.array=nil;
self.scopeBar=nil;
self.view=nil;
I am semi-new to Objective-c and confused with why my NSMutableDictionary is not retaining information. I am declaring my variable in the header file:
#interface view_searchResults : UIViewController <UITableViewDataSource, UITableViewDelegate> {
NSMutableDictionary *imageDicationary;
}
#property (nonatomic, retain) NSMutableDictionary *imageDictionary;
Then in my .m file, I have the following:
#synthesize imageDictionary;
-(UIImage *)getImageForURL:(NSURL*)url {
UIImage*image;
image = [UIImage imageWithData:[NSData dataWithContentsOfURL:url]];
[imageDictionary setObject:image forKey:#"test"];
if([imageDictionary objectForKey:#"test"]){
NSLog(#"Exists");
}
}
There is obviously other code to support this, but I can confirm that a URL is being passed, and the file is downloading correctly elsewhere. Also, I can confirm that this function is being executed, and I am not referring to the NSMutableDictionary anywhere else in the document.
Thanks!
Where do you create your NSMutable dictionary? If this really is all the code you have you need to create the dictionary:
#implementation view_searchResults
- (id) init;{
self = [super init];
if(self) {
imageDicationary = [NSMutableDictionary alloc] init]; // should also be released in dealloc.
}
return self;
}
If this is the error then the reason you are not causing a crash is because in objective-C it is valid to send a message to the nil object - it just does nothing.
You havent told us whether the "Exists" NSLog is executed, you also are NOT returning the image.
In other words, I fail to see your problem
Has imageDictionary been initialized? (alloc/init?)