My iPhone app is either crashing due to to a zombie, or leaking memory.. I've narrowed it down to 3 lines of code and can reliably get one of the two things to happen by commenting/uncommenting the code. The bugs occur when navigation between a list of results (tableView) and a details page containing a map and a few labels, memory leak happens the first time I navigation from the map back to the list of results, the zombie occurs after maybe 5/6 times navigating to different results and back.
#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
#define METERS_PER_MILE 1609.344
#interface ResDetailsPageVC : UIViewController <MKMapViewDelegate, UIAlertViewDelegate> {
UISegmentedControl *mapTypeSwitcher;
MKMapView *mapView;
UILabel *nameLabel;
UIButton *addressLabel;
UILabel *telephoneLabel;
NSString *address;
}
#property (nonatomic, retain) IBOutlet UISegmentedControl *mapTypeSwitcher;
#property (nonatomic, retain) IBOutlet MKMapView *mapView;
#property (nonatomic, retain) IBOutlet UILabel *nameLabel;
#property (nonatomic, retain) IBOutlet UIButton *addressLabel;
#property (nonatomic, retain) IBOutlet UILabel *telephoneLabel;
- (IBAction)segmentedControlIndexChanged;
- (IBAction)callButtonClick;
- (IBAction)addressClick;
- (void) callNumber;
#end
#synthesize mapView;
#synthesize mapTypeSwitcher;
#synthesize nameLabel, addressLabel, telephoneLabel;
- (void)dealloc {
// if these lines are commented out - memory leak
// if not - zombie?!
/*self.telephoneLabel = nil;
self.addressLabel = nil;
self.nameLabel = nil;*/
self.mapView = nil;
self.mapTypeSwitcher = nil;
[super dealloc];
}
Somewhere some other piece of code is using the same object whose address is stored in one of those three properties, but that other piece of code has not properly retained the object.
I recommend this to you:
- (void)dealloc {
[telephoneLabel release]; telephoneLabel = nil;
[addressLabel release]; addressLabel = nil;
....
[super dealloc];
}
Related
I'm trying to change the text of a UILabel with text from an array upon a button click, but it doesn't do anything.
#interface Test01AppDelegate : NSObject <UIApplicationDelegate> {
UILabel *helloLabel;
UIButton *hellobutton;
NSMutableArray *madWords;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet UIButton *hellowButton;
#property (nonatomic, retain) IBOutlet UILabel *hellowLabel;
#property (nonatomic, retain) NSMutableArray *madWords;
- (void) madArrays;
- (IBAction)helloYall;
#end
and
#import "Test01AppDelegate.h"
#implementation Test01AppDelegate
#synthesize window = _window;
#synthesize hellowButton;
#synthesize hellowLabel;
#synthesize madWords;
- (void) madArrays {
[madWords addObject:#"Part A"];
[madWords addObject:#"Part B"];
[madWords addObject:#"Part C"];
[madWords addObject:#"Part D"];
}
- (IBAction)helloYall {
[self madArrays];
self.hellowLabel.text = [madWords objectAtIndex:0];
}
I can set the helloLabel text with
#"some text here";
and it works fine. Also, I tried copying the "madArrays" method into the "helloYall" method and it still didn't work. As I said, I can manually set the text and it works, but I'd like to pull the info from an array. Eventually, I'd like to loop through the array to grab the text on each button press, but one step at a time. Thanks.
You never create the madWords array. You need to add:
self.madWords = [NSMutableArray array];
at the top of:
- (void) madArrays {
would probably be a good place. Other possibly good places would be i the class init method or the view controller viewWillAppear method.
// Or you can try this in your init Method:
//first allocate the ivar
- (void)myInitMethod {
madArrays = [[NSMutableArray]alloc]init];
}
//then you can do anything directly to the ivar or throughout de setter
- (void)doAnythingWithiVar {
// do your stuff
}
//when you are done you can dealloc your ivar
- (void)dealloc {
[madArrays release];
[super dealloc];
}
It looks like madArrays is still nil when you come to populate it. At some point you need something like [self setMadArrays:[[NSMutableArray alloc] init]];. Also, don't forget to release madArrays in the dealloc before calling super as you'll have a memory leak.
I want to call a function in a viewController from my appDelegate but with the following code, it doesn't get called. What am I doing wrong?
AppDelegate.h:
#import <UIKit/UIKit.h>
#import "DetailsToTransfer.h"
#class AccountDetailTransferViewController;
#interface AccountDetailTransferAppDelegate : NSObject <UIApplicationDelegate> {
DetailsToTransfer *objDetailsToTransfer;
}
#property (nonatomic, retain) DetailsToTransfer *objDetailsToTransfer;
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet AccountDetailTransferViewController *viewController;
-(void)sendToTransferScreen:(NSArray *)detailsArray;
#end
AppDelegate.m:
....
-(void)sendToTransferScreen:(NSArray *)detailsArray {
[objDetailsToTransfer setLabels:detailsArray];
objDetailsToTransfer = [[DetailsToTransfer alloc]initWithNibName:#"DetailsToTransfer" bundle:nil];
[self.window addSubview:objDetailsToTransfer.view];
}
DetailsToTransfer.h:
#import <UIKit/UIKit.h>
#interface DetailsToTransfer : UIViewController {
NSArray *accountDetailsArray;
UILabel *nameLabel;
UILabel *accountLabel;
IBOutlet UIButton *btnTransfer;
IBOutlet UIButton *btnBack;
}
#property (nonatomic, retain) NSArray *accountDetailsArray;
#property (nonatomic, retain) IBOutlet UILabel *nameLabel;
#property (nonatomic, retain) IBOutlet UILabel *accountLabel;
-(IBAction)sendDetails;
-(IBAction)goBack;
-(void)setLabels:(NSArray *)array;
#end
DetailsToTransfer.m
....
-(void)setLabels:(NSArray *)array {
NSLog(#"Setting Labels");
self.nameLabel.text = [array objectAtIndex:0];
self.accountLabel.text = [array objectAtIndex:1];
}
....
I would like to add that all the properties have been synthesized and that I'm calling the method in the appDelegate properly (i checked using NSLogs)
In AppDelegate.m:
Looks as if you are calling a method on your object before the object has been created. Until you have alloc / init your object, there will be no labels to set text.
Try changing your method to this:
-(void)sendToTransferScreen:(NSArray *)detailsArray {
if (!objDetailsToTransfer) {
objDetailsToTransfer = [[DetailsToTransfer alloc]initWithNibName:#"DetailsToTransfer" bundle:nil];
[objDetailsToTransfer setLabels:detailsArray];
[self.window addSubview:objDetailsToTransfer.view];
}
}
The problem might be that you are trying to set the values on a object that hasn't been created yet. I also provided an if statement to prevent the object from being created multiple times.
I have following code, instrument indicate that the pushViewController method has 32 bytes memory leak on device. Could you please kindly help check what rule I break? Should I change some "retain" to "assign" for declaration? Thanks in advance!
#interface GuideNewsViewController : UIViewController <UITableViewDataSource, UITableViewDelegate> {
#private
NSFetchedResultsController *fetchedResultsController;
NSManagedObjectContext *managedObjectContext;
UITableView *tableView;
NewsListViewController *newsListViewController;
}
#property (nonatomic, retain) NSManagedObjectContext *managedObjectContext;
#property (nonatomic, retain, readonly) NSFetchedResultsController *fetchedResultsController;
#property (nonatomic, retain) UITableView *tableView;
#property (nonatomic, retain, readonly) NewsListViewController *newsListViewController;
#implementation GuideNewsViewController
......
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
Member *member = [fetchedResultsController objectAtIndexPath:indexPath];
self.newsListViewController.managedObjectContext = self.managedObjectContext;
self.newsListViewController.title = member.memberName;
self.newsListViewController.author = member;
**// leak here**
[self.navigationController pushViewController:self.newsListViewController animated:YES];
}
......
#end
#interface NewsListViewController : UIViewController <UITableViewDataSource, UITableViewDelegate> {
#private
NSFetchedResultsController *fetchedResultsController;
NSManagedObjectContext *managedObjectContext;
UITableView *tableView;
Member *author;
}
#property (nonatomic, assign) NSManagedObjectContext *managedObjectContext;
#property (nonatomic, retain) UITableView *tableView;
#property (nonatomic, assign, readonly) NSFetchedResultsController *fetchedResultsController;
#property (nonatomic, assign) Member *author;
#end
Just a guess but, what happen if you change your newsListViewController from retain to assign?
I barely write retain, readonly together.
When does self.newsListViewController be released ? I don't think that point causes problem.
Generally, I pushViewController with following manner.
MySelfViewController *childView = [[MySelfViewController alloc] init];
// set up necessary properties of childView
...
// navigationController will release childView when it pops view controller.
[self pushViewController:childView animated:YES];
// release childView after pushViewController
[childView release];
If childView have to notify self something happened, it can use delegate to notify self.
Edit 1:
An example is as following.
// MySelfViewController.h
#protocol MySelfProtocol <NSObject>
- (void)notifySomethingHappened;
#end
#interface MySelfViewController : UIViewController {
id <MySelfProtocol> _delegate;
}
/// client init childview by pass self as parameter.
/// ex: Inside view controller A, he calls by
/// childView = [[MySelfViewController alloc] initWithDelegate:self];
- (id)initWithDelegate:(id)delegate;
/// other member methods
#end
// MySelfViewController.m
#implement MySelfViewController
- (id)initWithDelegate:(id)delegate
{
if (self = [super init])
{
/// assign policy.
/// childView should not retain parent view or delegate.
/// It is possible to let delegate never run dealloc.
_delegate = delegate;
/// custom initialization
....
}
return self;
}
- (void)someThingHappen
{
[_delegate notifySomethingHappend];
}
#end
I am trying to load a UIView with multiple data. The problem is data is not displays in first load but loads it in subsequent clicks. Can you help me trace the problem.
FirstViewController.h
#import <UIKit/UIKit.h>
#class SecondViewController;
#interface FirstViewController : UIViewController {
IBOutlet SecondViewController *mySecondViewController;
IBOutlet UIImageView *myimage1;
IBOutlet UIImageView *myimage2;
IBOutlet UILabel *mylabel1;
IBOutlet UILabel *mylabel2;
}
#property (nonatomic, retain) IBOutlet SecondViewController *mySecondViewController;
#property (nonatomic, retain) IBOutlet UIImageView *myimage1;
#property (nonatomic, retain) IBOutlet UIImageView *myimage2;
#property (nonatomic, retain) IBOutlet UILabel *mylabel1;
#property (nonatomic, retain) IBOutlet UILabel *mylabel2;
- (IBAction)bringNextView:(id)sender;
- (IBAction)bringNextView2: (id)sender;
#end
FirstViewController.m
#import "FirstViewController.h"
#import "SecondViewController.h"
#implementation FirstViewController
#synthesize mySecondViewController,myimage1, myimage2, mylabel1, mylabel2;
- (IBAction)bringNextView:(id)sender {
mySecondViewController.name.text = #"Paul";
mySecondViewController.myimageview.image = [UIImage imageNamed:#"Paul.png"];
mySecondViewController.statmsg.text = #"Doing iPhone Development";
[[self navigationController] pushViewController:mySecondViewController animated:YES];
}
SecondViewController.m
#import "SecondViewController.h"
#implementation SecondViewController
#synthesize myimageview, name, statmsg
- (void)viewDidLoad {
[self setTitle:#"Details"];
[super viewDidLoad];
}
Properties are not coming for the first time. But are displays after returning from view and then loading view again.
I am loading SecondViewController from FirstViewController.
Hi I have solved this. Actually I was pushing my view controller after setting up the property and that caused this issue.
Instead of :
mySecondViewController.name.text = #"Paul";
mySecondViewController.myimageview.image = [UIImage imageNamed:#"Paul.png"];
mySecondViewController.statmsg.text = #"Doing iPhone Development";
[[self navigationController] pushViewController:mySecondViewController animated:YES];
It should be :
[[self navigationController] pushViewController:mySecondViewController animated:YES];
mySecondViewController.name.text = #"Paul";
mySecondViewController.myimageview.image = [UIImage imageNamed:#"Paul.png"];
mySecondViewController.statmsg.text = #"Doing iPhone Development";
I have a method tied to four buttons. I want to create an array containing each button, and later retrieve and interact w/ a button from the array. The code I was tinkering with below. When I try to get a button from the array and send it a message, it goes kablooie.
Any thoughts on what I'm doing wrong?
Hack_DumpViewController.h
#import <UIKit/UIKit.h>
#interface Hack_DumpViewController : UIViewController {
IBOutlet UIButton *redButton;
IBOutlet UIButton *greenButton;
IBOutlet UIButton *blueButton;
IBOutlet UIButton *yellowButton;
NSArray *buttonMapping;
}
- (IBAction) changeToYo:(id)sender;
#property (nonatomic, retain) UIButton *redButton;
#property (nonatomic, retain) UIButton *greenButton;
#property (nonatomic, retain) UIButton *blueButton;
#property (nonatomic, retain) UIButton *yellowButton;
#property (nonatomic, retain) NSArray *buttonMapping;
#end
Hack_DumpViewController.m
#import "Hack_DumpViewController.h"
#implementation Hack_DumpViewController
#synthesize redButton;
#synthesize greenButton;
#synthesize yellowButton;
#synthesize blueButton;
#synthesize buttonMapping;
- (IBAction) changeToYo:(id)sender {
NSLog(#"changing numbers!");
for (UIButton *b in buttonMapping) {
[b setTitle:#"yo!"];
}
NSLog(#"changed to numbers!");
}
- (void)viewDidLoad {
buttonMapping = [[NSArray alloc] initWithObjects:greenButton, redButton, yellowButton, blueButton, nil];
}
[NSArray arrayWithObjects:...] returns an autoreleased array, so by the time you use it, it no longer exists and you end up messaging an invalid pointer. What you want is [[NSArray alloc] initWithObjects:...] (remembering to release it in your dealloc).
Why not tag the views in interface builder and then treat them like an array, much easier