I am developing iPhone Application.
MyApplicationData.h
#import <Foundation/Foundation.h>
#interface MyApplicationData : NSObject {
NSMutableArray* appData;
}
#property (retain) NSMutableArray* appData;
-(void)loadData;
-(void)addAppDataItemPrice:(NSString*)price itemCategory:(NSString*)category itemDate:(NSDate*)date;
-(void)forDebug;
+(id)instance;
#end
MyApplicationData.m
#import "MyApplicationData.h"
#implementation MyApplicationData
+ (id)instance
{
static MyApplicationData* _instance = nil;
if (!_instance) {
_instance = [[MyApplicationData alloc] init];
}
return _instance;
}
-(void)loadData{
appData = [NSMutableArray array];
NSLog(#"%#",appData);
}
-(void)forDebug{
}
-(void)addAppDataItemPrice:(NSString*)price itemCategory:(NSString*)category itemDate:(NSDate*)date{
NSLog(#"%#", appData);
[appData addObject:#"1"];
NSLog(#"%#", appData);
}
#end
another class
[[MyApplicationData instance] loadData];
one another class
[[MyApplicationData instance] addAppDataItemPrice:price itemCategory:category itemDate:date];
log
[Session started at 2009-11-03 21:04:41 +0900.]
2009-11-03 21:04:44.742 XXX[24002:207] (
)
2009-11-03 21:04:46.612 XXX[24002:207] (null)
It is not executed. What is the cause?
I think this line might be the cause:
appData = [NSMutableArray array];
try this instead:
appData = [[NSMutableArray alloc] init]
You'll want to make sure you release it as well when your MyApplicationData instance is destroyed (not critical in this case since it's a singleton, but still good practice)
It looks like your array is getting autoreleased after the method:
[[MyApplicationData instance] loadData];
I think it should be a member of the class, you can use the property syntax to help.
Set it up in the header file as:
#property (nonatomic, retain) NSMutableArray *appdata;
Then in the implementation:
#synthesize appdata;
Assign it as follows:
-(void)loadData{
self.appData = [NSMutableArray array];
}
Don't forget to release it in your dealloc method
When you set it in your code you can call it like the following:
[self.appData addObject:#"1"];
Related
Hey guys, I have this code within a function inside a class that is a subclass of NSOperation:
//...
#implementation DataLoader
#synthesize addedAnnotations;
#synthesize addedOverlays;
#synthesize loaderFunc;
#synthesize DLDelegate;
//...
-(id)initWithFunction:(LoaderFunc)func withDelegate:(id)delegate {
if (self = [super init]) {
self.addedOverlays = nil;
self.addedAnnotations = nil;
self.loaderFunc = func;
self.DLDelegate = delegate;
return self;
}
return nil;
}
//...
//inside a function
for (ParkingAnnotations *annotation in fetchedObjects) {
ParkingAnnotation *parkingAnnot = [[ParkingAnnotation alloc] init];
workingCoordinate.latitude = [[annotation latitude] doubleValue];
workingCoordinate.longitude = [[annotation longitude] doubleValue];
[parkingAnnot setCoordinate:workingCoordinate];
[parkingAnnot setTitle:[annotation valueForKey:#"lotName"]];
[parkingAnnot setAnnotationType:[annotation iconTypeRaw]];
[self.addedAnnotations addObject:parkingAnnot];//parkingAnnot not added to array here
[parkingAnnot release];
}
//...
Added annotations is an NSMutable array, I have been walking through this code with the debugger and for some reason the parkingAnnot object is not getting added to the array. Here is the relevant header code for the class:
//...
#interface DataLoader : NSOperation {
NSMutableArray *addedAnnotations;
NSMutableArray *addedOverlays;
LoaderFunc loaderfunc;
id <DataLoaderProtocol> DLDelegate;
}
#property (nonatomic, retain) NSMutableArray* addedAnnotations;
#property (nonatomic, retain) NSMutableArray* addedOverlays;
#property (nonatomic) LoaderFunc loaderFunc;
#property (assign) id DLDelegate;
//...
It is an astonishing problem because the function in which I am experiencing the problem was copied from my MapViewController and is essentially the same, but instead of mapView addAnnotation: I am adding to an NSMutable array instead. Any idea of what's up? Thanks in advance!
Where are you actually instantiating the addedAnnotations array? I only see it being assigned nil in your initialize function, maybe it should change to something like:
self.addedAnnotations = [[[NSMutableArray alloc] init] autorelease];
I've built a singleton object to manage some data in my app
#interface MyCommon : NSObject {
NSArray *quizz;
int iCurrentQuestion;
};
+ (MyCommon *)singleton;
#property (retain) NSArray *quizz;
#property (assign) int iCurrentQuestion;
#end
MyCommon.m
#import "MyCommon.h"
// MyCommon.m:
#implementation MyCommon
static MyCommon * MyCommon_Singleton = nil;
#synthesize iCurrentQuestion;
+ (MyCommon *)singleton
{
if (nil == MyCommon_Singleton)
{
MyCommon_Singleton = [[MyCommon alloc] init];
NSLog(#"allocating MyCommon_Singleton at %#",MyCommon_Singleton);
}
else {
NSLog(#"accessing singleton : %#", MyCommon_Singleton);
}
return MyCommon_Singleton;
}
- (NSArray*) getQuizz{
return quizz;
}
- (void) setQuizz:(NSArray *)array {
quizz = [NSArray arrayWithArray:array];
NSLog(#"setQuizz : %#",quizz);
}
There is no problem for writing the quizz object (setQuizz), however when I try to access it for reading, I get a crash : the quizz looks invalid and Xcode notify me an invalid CFArrayRef
I don't know what's wrong with my code.
You provide a custom setter for quizz but it doesn't comply with how the property is declared.
You're not retaining quizz when you're setting a new value. It's likely to be released just after, leading to a crash when you access it.
You should write
- (void)setQuizz:(NSArray *)array {
if (quizz != array) {
NSArray *tmp = quizz;
quizz = [array retain]; // retain the new value
[tmp release]; // release the old one
}
NSLog(#"setQuizz : %#",quizz);
}
this is way more code than it needs to be. First if you are going to be providing your own method you should declare so in the #property declaration which you didn't. Also your not properly retaining your variables. Additionally you should be using dispatch_once() for a thread safe & fast way to guarantee the singleton is only created once.
#interface MyCommon : NSObject {}
#property(nonatomic, retain) NSArray *quiz;
#property (assign) int iCurrentQuestion;
+ (MyCommon *)singleton;
#end
#implementation MyCommon
#synthesize quiz;
#synthesize iCurrentQuestion;
-(id)init {
self = [super init];
if(self) {
quiz = [[NSMutableArray alloc init];
iCurrentQuestion = 0;
}
return self;
}
+ (MyCommon *)singleton {
static MyCommon *singleton = nil;
static dispatch_once_t pred;
dispatch_once(&pred, ^{
singleton = [[MyCommon alloc] init];
});
return singleton;
}
#end
then you just do
[MyCommon singleton].quiz = //some array
I have an NSMutableArray defined as a property, synthesized and I have assigned a newly created instance of an NSMutableArray. But after this my application always crashes whenever I try adding an object to the NSMutableArray.
Page.h
#interface Page : NSObject
{
NSString *name;
UIImage *image;
NSMutableArray *questions;
}
#property (nonatomic, copy) NSString *name;
#property (nonatomic, retain) UIImage *image;
#property (nonatomic, copy) NSMutableArray *questions;
#end
Page.m
#implementation Page
#synthesize name, image, questions;
#end
Relevant code
Page *testPage = [[Page alloc] init];
testPage.image = [UIImage imageNamed:#"Cooperatief leren Veenman-11.jpg"];
testPage.name = [NSString stringWithString:#"Cooperatief leren Veenman-11.jpg"];
testPage.questions = [[NSMutableArray alloc] init];
[testPage.questions addObject:[NSNumber numberWithFloat:arc4random()]];
The debugger reveals that the moment I use testPage.questions = [[NSMutableArray alloc] init]; the type of testPage.questions changes from NSMutableArray* to __NSArrayL* (or __NSArrayI*, not sure). I suspect this to be the problem, but I find it extremely odd. Anyone know what's happening here?
The problem is that you've declared the property as copy. This means your setter is going to be implemented something like this:
- (void) setQuestions:(NSMutableArray *)array {
if (array != questions) {
[questions release];
questions = [array copy];
}
}
The kicker here is that if you -copy an array (whether immutable or mutable), you will always get an immutable NSArray.
So to fix this, change the property to be retain instead of copy, and also fix this memory leak:
testPage.questions = [[NSMutableArray alloc] init];
It should be:
testPage.questions = [NSMutableArray array];
#property (nonatomic, copy) This setter declaration "copy" probably cast to NSArray why not retain or assign? I would retain anyway
You can also create a mutable copy method like so:
- (void)setQuestions:(NSMutableArray *)newArray
{
if (questions != newArray)
{
[questions release];
questions = [newArray mutableCopy];
}
}
This is really twisting my mind… I'm trying to access an NSMutableArray in an IBAction which I defined in viewDidLoad. Unfortunately I keep getting a EXC_BAD_ACCESS.
I'm new to all this so I'd really appreciate some insight in what I'm doing wrong.
Below find the corresponding code excerpts.
CounterViewController.h:
#interface CounterViewController : UIViewController{
NSMutableArray *countHistoryArray;
}
#property(nonatomic, retain) NSMutableArray *countHistoryArray;
CounterViewController.m:
#implementation CounterViewController
#synthesize countHistoryArray;
- (void)viewDidLoad {
[super viewDidLoad];
//Fill array with some dummy data
self.countHistoryArray = [[NSMutableArray alloc] init];
NSDate *now = [[[NSDate alloc] init] autorelease];
CurrentCount *historicCount = [[[CurrentCount alloc]
initWithCount:[NSNumber numberWithInteger:22]
description:#"Testcount"
dateAndTime:now] autorelease];
[self.countHistoryArray addObject: historicCount];
//Do some logging - everything is working fine here!
NSLog(#"%#", [self.countHistoryArray description]);
}
//Later on we click on a button and want to use the array
- (IBAction)doSomeStuff {
//Let's look at the array again - and now it crashes with EXC_BAD_ACCESS
NSLog(#"%#", [self.countHistoryArray description]);
}
Thanks a lot!
Manuel
EDIT Additional code as asked for by #jamapag
CurrentCount.h
#import <Foundation/Foundation.h>
#interface CurrentCount : NSObject {
NSNumber *counterLevel;
NSString *description;
NSDate *dateAndTime;
}
- (id)initWithCount:(NSNumber *)newCounterLevel description:(NSString *)newDescription dateAndTime:(NSDate *)newDateAndTime;
#property(nonatomic, copy) NSNumber *counterLevel;
#property(nonatomic, copy) NSString *description;
#property(nonatomic, copy) NSDate *dateAndTime;
#end
CurrentCount.m
#import "CurrentCount.h"
#implementation CurrentCount
#synthesize counterLevel;
#synthesize description;
#synthesize dateAndTime;
- (id)initWithCount:(NSNumber *)newCounterLevel description:(NSString *)newDescription dateAndTime:(NSDate *)newDateAndTime{
self = [super init];
if(nil != self){
self.counterLevel = newCounterLevel;
self.description = newDescription;
self.dateAndTime = newDateAndTime;
}
return self;
}
-(void) dealloc{
self.counterLevel = nil;
self.description = nil;
self.dateAndTime = nil;
[super dealloc];
}
#end
Are you sure that your code actually looks like this?
- (IBAction)doSomeStuff {
//Let's look at the array again - and now it crashes with EXC_BAD_ACCESS
NSLog(#"%#", [self.countHistoryArray description]);
}
Your question title says "NSMutableArray count causes EXC_BAD_ACCESS" - if that line of code actually says NSLog(#"%#", [self.countHistoryArray count]);, you'll almost certainly get a crash, since NSLog will attempt to treat a primitive type (the type returned by -[NSArray count]) as an object. In order to use -[NSArray count] in NSLog, use %u instead of %#:
- (IBAction)doSomeStuff {
// This time it should work!
NSLog(#"Array Count = %u", [self.countHistoryArray count]);
}
Remove autorelease from:
currentCount *historicCount = [[[CurrentCount alloc]
initWithCount:[NSNumber numberWithInteger:22]
description:#"Testcount"
dateAndTime:now] autorelease];
It looks like you are accidentally releasing countHistoryArray somewhere. Try removing all calls to it except for those two you showed. Additionally you can try enabling zombies to debug the problem.
Oh and by the way you probably don't really want a public NSMutableArray property and if you do you probably want it to be copy, not retain. Otherwise incapsulation kinda goes down the drain.
I know this question has already been solved and accepted but its for others who are or will face this issue.
I was facing the same issue, I tried all solutions but no solution worked for me. The project I am working on is NON-ARC.
I tried and made a simple change in property
Previously my property for NSMUTABLEARRAY was
#property (nonatomic, assign) NSMutableArray * dataArray;
I changed it to:
#property (nonatomic, retain) NSMutableArray * dataArray;
Changed it from ASSIGN to RETAIN
And it solved my problem
I am getting errors when trying to add items to a NSMutableArray which is encapsulated within an object.
Code follows:
#import <Foundation/Foundation.h>
#interface TestObject : NSObject {
NSMutableArray *myArray;
}
#property (nonatomic, retain) NSMutableArray *myArray;
#end
#import "TestObject.h"
#implementation TestObject
#synthesize myArray;
- (id) init {
if(self= [super init]){
// Initialise the Mutable Array
myArray = [[NSMutableArray alloc] init];
}
return self;
}
- (void) dealloc {
[super dealloc];
[myArray release];
}
#end
Calling:
TestObject *testObject = [[TestObject alloc] init];
NSString *someString = #"blah blah blah";
NSLog(#"%#", someString);
[testObject.myArray addObject:someString];
NSLog(#"Test Object Array Count: %#", [testObject.myArray count]);
[testObject release];
Can anyone tell me why this throws an error when calling count?
I have also tried the copy the Mutable Array to a local variable and get the same result when calling count on the local variable.
Warning warning warning!!!
[super dealloc] is the last thing you should do in your -dealloc method, not the first!
It's a good thing it just showed a warning, when I have done the same it has crashed.
The reason is that %# is an object placeholder. But the count method returns NSInteger which is a primitive datatype and the placeholder for it is %d, as you have correctly noted in the comment.