ios - Objective-C calling instance method within Singleton -

-

i created singleton class named datamanager. i've set caching. however, when attempting call cache instance methods within instance method of datamanager, i'm getting exc_bad_access error on line:

nsmutablearray *stops = [[datamanager sharedinstance] getcacheforkey:@"stops"];

datamanager.h

@interface datamanager : nsobject {     fmdatabase *db;     nsmutabledictionary *cache; }  + (datamanager *)sharedinstance; // ... more methods - (id)getcacheforkey:(nsstring *)key; - (void)setcacheforkey:(nsstring *)key withvalue:(id)value; - (void)clearcache;

datamanager.m

- (nsarray *)getstops:(nsinteger)archived {     nsmutablearray *stops = [[datamanager sharedinstance] getcacheforkey:@"stops"];     if (stops != nil) {         nslog(@"stops: %@", stops);         return stops;     }      stops = [nsmutablearray array];     // set stops...      [[datamanager sharedinstance] setcacheforkey:@"stops" withvalue:stops];      return stops; }

it seems occur when called view controller. first view controller no error, second view controller, error.

this first attempt @ singleton, i'm sure making simple mistake. failing see myself.

note: i've tried [self getcache...] same result.

update

here singleton implementation. adapted http://www.galloway.me.uk/tutorials/singleton-classes/

+ (datamanager *)sharedinstance {     @synchronized(self) {         if (!instance) {             instance = [[super allocwithzone:null] init];         }     }      return instance; }  + (id)allocwithzone:(nszone *)zone {     return [[self sharedinstance] retain]; }  - (id)copywithzone:(nszone *)zone {     return self; }  - (id)retain {     return self; }  - (unsigned)retaincount {     return uint_max; }  - (oneway void)release {     // never release }  - (id)autorelease {     return self; }  - (id)init {     if (self = [super init]) {                 if (db == nil){             bourbonappdelegate *appdelegate = (bourbonappdelegate *)[[uiapplication sharedapplication] delegate];             [appdelegate createeditablecopyofdatabaseifneeded];             db = [[fmdatabase alloc] initwithpath:[appdelegate getdbpath]];         }          if (![db open]) {             nsassert(0, @"failed open database.");             [db release];              return nil;         }          [db settraceexecution:yes];                 [db setlogserrors:true];          cache = [nsmutabledictionary dictionary];         nslog(@"cache: %@", cache);     }      return self; }

your cache object autoreleased, it's no longer in memory when try access it.

use [nsmutabledictionary alloc] init] instead of [nsmutabledictionary dictionary] instance retained.


Comments

Post a Comment

Popular posts from this blog

c# - SVN Error : "svnadmin: E205000: Too many arguments" -

-
i trying reposotries using c# code process svncommand = null; var psi = new processstartinfo("svnadmin"); psi.redirectstandardoutput = true; psi.redirectstandarderror = true; psi.useshellexecute = false; psi.arguments= @"dump c:\repositories\myrepo > c:\temp\myrepodumpfile.dump"; using (svncommand = process.start(psi)) { var myoutput = svncommand.standardoutput; var myerror = svncommand.standarderror; debug.write("output :" + environment.newline + environment.newline + myoutput.readtoend() + environment.newline + "error :" + environment.newline + environment.newline + myerror.readtoend()); svncommand.close(); } when use dump command commandline svnadmin dump c:\repositories\myrepo > c:\temp\myrepodumpfile.dump it works fine when try ...
Read more

c# - Copy ObservableCollection to another ObservableCollection -

-
how copy observablecollection item observablecollection without reference of first collection? here observablecollection item value changes affecting both collections. code private observablecollection<ratemodel> _allmetalrate = new observablecollection<ratemodel>(); private observablecollection<ratemodel> _metalrateondate = new observablecollection<ratemodel>(); public observablecollection<ratemodel> allmetalrate { { return this._allmetalrate; } set { this._allmetalrate = value; notifypropertychanged("metalrate"); } } public observablecollection<ratemodel> metalrateondate { { return this._metalrateondate; } set { this._metalrateondate = value; notifypropertychanged("metalrateondate"); } } foreach (var item in metalrateondate) allmetalrate.add(item); what causing , how can solve it? you need clone object referenced item before it's a...
Read more

All overlapping substrings matching a java regex -

-
is there api method returns (possibly overlapping) substrings match regular expression? for example, have text string: string t = 04/31 412-555-1235; , , have pattern: pattern p = new pattern("\\d\\d+"); matches strings of 2 or more characters. the matches are: 04, 31, 412, 555, 1235. how overlapping matches? i want code return: 04, 31, 41, 412, 12, 55, 555, 55, 12, 123, 1235, 23, 235, 35. theoretically should possible -- there obvious o(n^2) algorithm enumerates , checks substrings against pattern. edit rather enumerating substrings, safer use region(int start, int end) method in matcher . checking pattern against separate, extracted substring might change result of match (e.g. if there non-capturing group or word boundary check @ start/end of pattern). edit 2 actually, it's unclear whether region() expect zero-width matches. specification vague, , experiments yield disappointing results. for example: string line = "xx90xx"; strin...
Read more