Memory Management with code

Question

hi i have 2 classes one is plisreader which is following code

//
//  PlistReader.h
//  NationalAntemsAndFlags
//
//  Created by mac on 12/17/11.
//  Copyright (c) 2011 __MyCompanyName__. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "CountryClass.h"

@interface PlistReader : NSObject
{
    NSDictionary *temp;
}
@property (nonatomic,retain) NSDictionary *temp;

-(int)LengthOfPList;
-(id)GetTheObjectById:(NSString*)ObjId;
-(void)initWithFileName:(NSString*)fileName;
- (id)getCountryInfoById:(int)id;
@end

//implementation file

//
//  PlistReader.m
//  NationalAntemsAndFlags
//
//  Created by mac on 12/17/11.
//  Copyright (c) 2011 __MyCompanyName__. All rights reserved.
//

#import "PlistReader.h"

@implementation PlistReader
@synthesize temp;


-(id)init
{
    if(self =[super init])
    {

    }
    return self;
}
-(void)initWithFileName:(NSString*)fileName
{
    // Data.plist code
    // get paths from root direcory

    NSArray *paths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES);
    // get documents path
    NSString *documentsPath = [paths objectAtIndex:0];
    // get the path to our Data/plist file
    NSString *plistPath = [documentsPath stringByAppendingPathComponent:[fileName stringByAppendingString:@"plist"]];

    // check to see if Data.plist exists in documents
    if (![[NSFileManager defaultManager] fileExistsAtPath:plistPath])
    {
        // if not in documents, get property list from main bundle
        plistPath = [[NSBundle mainBundle] pathForResource:fileName ofType:@"plist"];
    }

    // read property list into memory as an NSData object
    NSData *plistXML = [[NSFileManager defaultManager] contentsAtPath:plistPath];
    NSString *errorDesc = nil;
    NSPropertyListFormat format;
    // convert static property liost into dictionary object
    temp =(NSDictionary *)[NSPropertyListSerialization propertyListFromData:plistXML mutabilityOption:NSPropertyListMutableContainersAndLeaves format:&format errorDescription:&errorDesc];
    if (!temp)
    {
        NSLog(@"Error reading plist: %@, format: %d", errorDesc, format);
    }
    // assign values

}

-(int)LengthOfPList
{
    return temp.count;
}
-(id)GetTheObjectById:(NSString*)ObjId
{

   return [temp objectForKey:ObjId];

}
-(id)getCountryInfoById:(int)objId
{

    NSString *objsId = [NSString stringWithFormat:@"%d",objId];
    NSDictionary *CDirectory = (NSDictionary*) [self GetTheObjectById:objsId];
    int count = CDirectory.count;
    if(count>0)
    {
        CountryClass *objCountry = [[CountryClass alloc] init];   
        objCountry.Name= [CDirectory objectForKey:@"Name"];
        objCountry.LocationX =[[CDirectory objectForKey:@"PositionX"] intValue];
        objCountry.LocationY = [[CDirectory objectForKey:@"PositionY"] intValue];
        objCountry.ImageUrl = [CDirectory objectForKey:@"ImageUrl"];
        objCountry.AnthemUrl =[CDirectory objectForKey:@"AnthemUrl"];
        objCountry.ShortDetail =[CDirectory objectForKey:@"short Info"];
        objCountry.completeDetails = [CDirectory objectForKey:@"Details"];
        id ObjCountryInfo= objCountry;
        [objCountry release];
        return ObjCountryInfo;
    }
    return NULL;
}

-(void)dealloc
{
    NSLog(@"dealloc plist");
    [temp release];
    [super dealloc];
}




@end

and the other is country class which has following code

//
//  CountryClass.h
//  NationalAntemsAndFlags
//
//  Created by mac on 12/17/11.
//  Copyright (c) 2011 __MyCompanyName__. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface CountryClass : NSObject
{
    NSString *Name ;
    NSString *ImageUrl;
    NSString *AnthemUrl;
    NSString *ShortDetail;
    NSString *completeDetails;
    int LocationX ;
    int LocationY ;


}
@property (nonatomic,retain) IBOutlet NSString *Name;
@property (nonatomic,retain) IBOutlet NSString *ImageUrl;
@property (nonatomic,retain) IBOutlet NSString *AnthemUrl;
@property (nonatomic,retain) IBOutlet NSString *ShortDetail;
@property (nonatomic,retain) IBOutlet NSString *completeDetails;
@property (nonatomic) IBOutlet int LocationY;
@property (nonatomic) IBOutlet int LocationX;



@end

implementation file

//
//  CountryClass.m
//  NationalAntemsAndFlags
//
//  Created by mac on 12/17/11.
//  Copyright (c) 2011 __MyCompanyName__. All rights reserved.
//

#import "CountryClass.h"

@implementation CountryClass

@synthesize Name,ImageUrl,AnthemUrl,ShortDetail,completeDetails,LocationX,LocationY;


@end

so i called this in my scene like this

-(void)LoadData:(int)countryId
{
    CId = countryId;
    PlistReader *pList =[[PlistReader alloc]init];
    [pList initWithFileName:@"CountryDetails"];   

    CountryClass *objcountry = (CountryClass*) [pList getCountryInfoById:countryId];

    NSString *tempLongDetails = objcountry.completeDetails;
    NSString *tempShortDetails = objcountry.ShortDetail;
    NSString *fileName =  objcountry.ImageUrl ;
    CCSprite *flag ;

    NSString * fullPath = [[NSBundle mainBundle] pathForResource: [fileName stringByDeletingPathExtension]
                                                             ofType: [fileName pathExtension]
                                                           inDirectory: @"CountryFlags"];


    NSLog(fullPath);
    if (fullPath)
    {
       UIImage  *theImage = [UIImage imageWithContentsOfFile: fullPath];
       if (theImage)
       {
            flag = [CCSprite spriteWithCGImage: [theImage CGImage] key: fileName];
           // flag = [CCSprite spriteWithFile:fileName];
            flag.position = ccp(200, 265);
           flag.scale = .255;
       }
    }



    TextViewTopFlagData = [[UITextView alloc]init];
    TextViewTopFlagData.text = tempShortDetails;
    TextViewTopFlagData.frame = CGRectMake(260,17, 105, 75);
    TextViewTopFlagData.backgroundColor = [UIColor clearColor];
    [TextViewTopFlagData setEditable:NO];


    TextViewDownFlagData = [[UITextView alloc]init];
    TextViewDownFlagData.text = tempLongDetails;
    TextViewDownFlagData.frame = CGRectMake(22,240, 242, 61);
    TextViewDownFlagData.backgroundColor = [UIColor clearColor];
    [TextViewDownFlagData setEditable:NO];
    [[[CCDirector sharedDirector]openGLView]addSubview:TextViewTopFlagData];
    [[[CCDirector sharedDirector]openGLView]addSubview:TextViewDownFlagData];
    [self addChild:flag];

}

@end

but at the end of the function objcountry will be empty or out of reference can any one explain me that why this is happaning

Please only include code that actually references the problem you are talking about, this is far too long. — jrturton, Dec 19 '11 at 16:40
i thought may be people can't understand what i am trying to say that why i put all the code here main problem is that objcountry lost value or destroyed at the end of the function so why is happening that — precious.logic, Dec 19 '11 at 16:45
@precious.logic You can edit this question using the "edit" link below it. No need to delete and repost. — Adam Lear, Dec 22 '11 at 05:20

score 0 · Answer 1 · edited May 23 '17 at 12:20

Just glancing though your code, this jumps out at me :

temp =(NSDictionary *)[NSPropertyListSerialization propertyListFromData:plistXML mutabilityOption:NSPropertyListMutableContainersAndLeaves format:&format errorDescription:&errorDesc];

You need to retain it, like this :

temp = [(NSDictionary *)[NSPropertyListSerialization propertyListFromData:plistXML mutabilityOption:NSPropertyListMutableContainersAndLeaves format:&format errorDescription:&errorDesc] retain];

This won't help your bug but it's good practice not to retain properties that have a mutable subclass (i.e. NSString has NSMutableString, NSSet has NSMutableSet, NSDictionary has NSMutableDictionary). It's better (safer) to copy them instead. i.e.

@property (nonatomic, retian) NSString *name; // worse
@property (nonatomic, copy) NSString *name; // better

For the reasons why, read the accepted answer here

thanks bro it's good information i will try it then tell you if it work or not but thanks — precious.logic, Dec 19 '11 at 18:01

score 0 · Answer 2 · answered Dec 22 '11 at 00:07

Is there a meaning this function is returning (id) instead of (CountryClass*)

-(id)getCountryInfoById:(int)objId
{

    NSString *objsId = [NSString stringWithFormat:@"%d",objId];
    NSDictionary *CDirectory = (NSDictionary*) [self GetTheObjectById:objsId];
    int count = CDirectory.count;
    if(count>0)
    {
        CountryClass *objCountry = [[CountryClass alloc] init];   
        objCountry.Name= [CDirectory objectForKey:@"Name"];
        objCountry.LocationX =[[CDirectory objectForKey:@"PositionX"] intValue];
        objCountry.LocationY = [[CDirectory objectForKey:@"PositionY"] intValue];
        objCountry.ImageUrl = [CDirectory objectForKey:@"ImageUrl"];
        objCountry.AnthemUrl =[CDirectory objectForKey:@"AnthemUrl"];
        objCountry.ShortDetail =[CDirectory objectForKey:@"short Info"];
        objCountry.completeDetails = [CDirectory objectForKey:@"Details"];
        id ObjCountryInfo= objCountry;
        [objCountry release];
        return ObjCountryInfo;
    }
    return NULL;
}

Your problem is that you release the objCountry before returning it and referencing it to an id-object.

    id ObjCountryInfo= objCountry;
    [objCountry release];
    return ObjCountryInfo;

My suggestion is not to release the countryObject in this method (release it when you are done with it) and changing the return-type to CountryClass*

Memory Management with code

2 Answers2