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POHow to manage memory using classes in Objective-C?
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2010-12-29T09:07:45.947
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This is my first time creating an iPhone App and I am having difficulty with the memory management because I have never had to deal with it before. I have a UITableViewController and it all works fine until I try to scroll down in the simulator. It crashes saying that it cannot allocate that much memory. I have narrowed it down to where the crash is occurring: <pre><code> - (UITableViewCell *)tableView:(UITableView *)aTableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { // Dequeue or create a cell UITableViewCellStyle style = UITableViewCellStyleDefault; UITableViewCell *cell = [aTableView dequeueReusableCellWithIdentifier:@"BaseCell"]; if (!cell) cell = [[[UITableViewCell alloc] initWithStyle:style reuseIdentifier:@"BaseCell"] autorelease]; NSString* crayon; // Retrieve the crayon and its color if (aTableView == self.tableView) { crayon = [[[self.sectionArray objectAtIndex:indexPath.section] objectAtIndex:indexPath.row] getName]; } else { crayon = [FILTEREDKEYS objectAtIndex:indexPath.row]; } cell.textLabel.text = crayon; if (![crayon hasPrefix:@"White"]) cell.textLabel.textColor = [self.crayonColors objectForKey:crayon]; else cell.textLabel.textColor = [UIColor blackColor]; return cell; } </code></pre> Here is the getName method: <pre><code>- (NSString*)getName { return name; } </code></pre> name is defined as: <pre><code>@property (nonatomic, retain) NSString *name; </code></pre> Now sectionArray is an NSMutableArray with instances of a class that I created Term in it. Term has a method getName that returns a NSString*. The problem seems to be the part of where crayon is being set and getName is being called. I have tried adding autorelease, release, and other stuff like that but that just causes the entire app to crash before even launching. Also if I do: <pre><code>cell.textLabel.text = @"test"; //crayon; /*if (![crayon hasPrefix:@"White"]) cell.textLabel.textColor = [self.crayonColors objectForKey:crayon]; else cell.textLabel.textColor = [UIColor blackColor];*/ </code></pre> Then I get no error whatsoever and it all scrolls just fine. Thanks in advance for the help! Edit: Here is the full Log of when I try to run the app and the error it gives when it crashes: <blockquote> [Session started at 2010-12-29 04:23:38 -0500.] [Session started at 2010-12-29 04:23:44 -0500.] GNU gdb 6.3.50-20050815 (Apple version gdb-967) (Tue Jul 14 02:11:58 UTC 2009) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i386-apple-darwin".sharedlibrary apply-load-rules all Attaching to process 1429. gdb-i386-apple-darwin(1430,0x778720) malloc: * mmap(size=1420296192) failed (error code=12) error: can't allocate region ** set a breakpoint in malloc_error_break to debug gdb stack crawl at point of internal error: [ 0 ] /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/libexec/gdb/gdb-i386-apple-darwin (align_down+0x0) [0x1222d8] [ 1 ] /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/libexec/gdb/gdb-i386-apple-darwin (xstrvprintf+0x0) [0x12336c] [ 2 ] /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/libexec/gdb/gdb-i386-apple-darwin (xmalloc+0x28) [0x12358f] [ 3 ] /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/libexec/gdb/gdb-i386-apple-darwin (dyld_info_read_raw_data+0x50) [0x1659af] [ 4 ] /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/libexec/gdb/gdb-i386-apple-darwin (dyld_info_read+0x1bc) [0x168a58] [ 5 ] /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/libexec/gdb/gdb-i386-apple-darwin (macosx_dyld_update+0xbf) [0x168c9c] [ 6 ] /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/libexec/gdb/gdb-i386-apple-darwin (macosx_solib_add+0x36b) [0x169fcc] [ 7 ] /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/libexec/gdb/gdb-i386-apple-darwin (macosx_child_attach+0x478) [0x17dd11] [ 8 ] /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/libexec/gdb/gdb-i386-apple-darwin (attach_command+0x5d) [0x64ec5] [ 9 ] /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/libexec/gdb/gdb-i386-apple-darwin (mi_cmd_target_attach+0x4c) [0x15dbd] [ 10 ] /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/libexec/gdb/gdb-i386-apple-darwin (captured_mi_execute_command+0x16d) [0x17427] [ 11 ] /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/libexec/gdb/gdb-i386-apple-darwin (catch_exception+0x41) [0x7a99a] [ 12 ] /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/libexec/gdb/gdb-i386-apple-darwin (mi_execute_command+0xa9) [0x16f63] /SourceCache/gdb/gdb-967/src/gdb/utils.c:1144: internal-error: virtual memory exhausted: can't allocate 1420296192 bytes. A problem internal to GDB has been detected, further debugging may prove unreliable. The Debugger has exited with status 1.The Debugger has exited with status 1. </blockquote> <hr> Here is the backtrace that I get when I set the breakpoint for malloc_error_break: <pre><code>#0 0x0097a68c in objc_msgSend () #1 0x01785bef in -[UILabel setText:] () #2 0x000030e0 in -[TableViewController tableView:cellForRowAtIndexPath:] (self=0x421d760, _cmd=0x29cfad8, aTableView=0x4819600, indexPath=0x42190f0) at /Volumes/Main2/Enayet/TableViewController.m:99 #3 0x016cee0c in -[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:withIndexPath:] () #4 0x016c6a43 in -[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:] () #5 0x016d954f in -[UITableView(_UITableViewPrivate) _updateVisibleCellsNow] () #6 0x016d08ff in -[UITableView layoutSubviews] () #7 0x03e672b0 in -[CALayer layoutSublayers] () #8 0x03e6706f in CALayerLayoutIfNeeded () #9 0x03e668c6 in CA::Context::commit_transaction () #10 0x03e6653a in CA::Transaction::commit () #11 0x03e6e838 in CA::Transaction::observer_callback () #12 0x00b00252 in __CFRunLoopDoObservers () #13 0x00aff65f in CFRunLoopRunSpecific () #14 0x00afec48 in CFRunLoopRunInMode () #15 0x00156615 in GSEventRunModal () #16 0x001566da in GSEventRun () #17 0x01689faf in UIApplicationMain () #18 0x00002398 in main (argc=1, argv=0xbfffefb0) at /Volumes/Main2/Enayet/main.m:14 </code></pre> <h2>--------</h2> <hr> Here is my complete source for the UITableViewController class: <pre><code>// // TableViewController.m // Enayet // // Created by Filip on 12/27/10. // Copyright 2010 __MyCompanyName__. All rights reserved. // #import "TableViewController.h" #import "EnayetAppDelegate.h" @implementation TableViewController @synthesize crayonColors; @synthesize filteredArray; @synthesize sectionArray; @synthesize searchBar; @synthesize searchDC; - (TableViewController*) initToCall:(NSMutableDictionary*) toUseArray { self = [super initWithStyle:UITableViewStylePlain]; crayonColors = toUseArray; return self; } - (NSInteger)numberOfSectionsInTableView:(UITableView *)aTableView { if (aTableView == self.tableView) return 26; return 1; } // Via Jack Lucky - (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar { [self.searchBar setText:@""]; } - (NSString *)tableView:(UITableView *)aTableView titleForHeaderInSection:(NSInteger)section { if (aTableView == self.tableView) { if ([[self.sectionArray objectAtIndex:section] count] == 0) return nil; //return [NSString stringWithFormat:@"%@", [[ALPHA substringFromIndex:section] substringToIndex:1]]; return [[ALPHA substringFromIndex:section] substringToIndex:1]; } else return nil; } - (NSInteger)tableView:(UITableView *)aTableView numberOfRowsInSection:(NSInteger)section { // Normal table if (aTableView == self.tableView) return [[self.sectionArray objectAtIndex:section] count]; // Search table NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF contains[cd] %@", self.searchBar.text]; self.filteredArray = [self.crayonColors.allKeys filteredArrayUsingPredicate:predicate]; return self.filteredArray.count; } // Convert a 6-character hex color to a UIColor object - (UIColor *) getColor: (NSString *) hexColor { unsigned int red, green, blue; NSRange range; range.length = 2; range.location = 0; [[NSScanner scannerWithString:[hexColor substringWithRange:range]] scanHexInt:&red]; range.location = 2; [[NSScanner scannerWithString:[hexColor substringWithRange:range]] scanHexInt:&green]; range.location = 4; [[NSScanner scannerWithString:[hexColor substringWithRange:range]] scanHexInt:&blue]; return [UIColor colorWithRed:(float)(red/255.0f) green:(float)(green/255.0f) blue:(float)(blue/255.0f) alpha:1.0f]; } - (UITableViewCell *)tableView:(UITableView *)aTableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { // Dequeue or create a cell UITableViewCellStyle style = UITableViewCellStyleDefault; UITableViewCell *cell = [aTableView dequeueReusableCellWithIdentifier:@"BaseCell"]; if (!cell) cell = [[[UITableViewCell alloc] initWithStyle:style reuseIdentifier:@"BaseCell"] autorelease]; NSString* crayon; // Retrieve the crayon and its color if (aTableView == self.tableView) { Term *term = (Term *) [[self.sectionArray objectAtIndex:indexPath.section] objectAtIndex:indexPath.row]; crayon = [term name]; } else { crayon = [FILTEREDKEYS objectAtIndex:indexPath.row]; } cell.textLabel.text = crayon; if (![crayon hasPrefix:@"White"]) cell.textLabel.textColor = [self.crayonColors objectForKey:crayon]; else cell.textLabel.textColor = [UIColor blackColor]; return cell; } // Grouped Tables do not support section indices (even though they kind of do) - (NSArray *)sectionIndexTitlesForTableView:(UITableView *)aTableView { if (aTableView == self.tableView) // regular table { NSMutableArray *indices = [NSMutableArray arrayWithObject:UITableViewIndexSearch]; for (int i = 0; i < 26; i++) if ([[self.sectionArray objectAtIndex:i] count]) [indices addObject:[[ALPHA substringFromIndex:i] substringToIndex:1]]; // [indices addObject:@"\ue057"]; // <-- using emoji return indices; } else return nil; // search table } - (NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index { if (title == UITableViewIndexSearch) return 0; return [ALPHA rangeOfString:title].location; } - (void)goToTwo:(Term*) toGive { EnayetAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate]; [appDelegate setTerm:toGive]; [appDelegate displayView:2]; } // Respond to user selections by updating tint colors - (void)tableView:(UITableView *)aTableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { if (aTableView == self.tableView) { [self goToTwo:[[self.sectionArray objectAtIndex:indexPath.section] objectAtIndex:indexPath.row]]; } } - (void) viewDidLoad { // Prepare the crayon color dictionary NSString *pathname = [[NSBundle mainBundle] pathForResource:@"crayons" ofType:@"txt" inDirectory:@"/"]; NSArray *rawCrayons = [[NSString stringWithContentsOfFile:pathname encoding:NSUTF8StringEncoding error:nil] componentsSeparatedByString:@"\n"]; self.crayonColors = [NSMutableDictionary dictionary]; self.sectionArray = [NSMutableArray array]; for (int i = 0; i < 26; i++) [self.sectionArray addObject:[NSMutableArray array]]; for (NSString *string in rawCrayons) { [self.crayonColors setObject:CRAYON_COLOR(string) forKey:CRAYON_NAME(string)]; NSUInteger firstLetter = [ALPHA rangeOfString:[string substringToIndex:1]].location; if (firstLetter != NSNotFound) [[self.sectionArray objectAtIndex:firstLetter] addObject:[[Term alloc] initToCall:CRAYON_NAME(string)]]; } //NSLog(@"%@", sectionArray); // Create a search bar self.searchBar = [[[UISearchBar alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, 44.0f)] autorelease]; self.searchBar.tintColor = COOKBOOK_PURPLE_COLOR; self.searchBar.autocorrectionType = UITextAutocorrectionTypeNo; self.searchBar.autocapitalizationType = UITextAutocapitalizationTypeNone; self.searchBar.keyboardType = UIKeyboardTypeAlphabet; self.tableView.tableHeaderView = self.searchBar; // Create the search display controller self.searchDC = [[[UISearchDisplayController alloc] initWithSearchBar:self.searchBar contentsController:self] autorelease]; self.searchDC.searchResultsDataSource = self; self.searchDC.searchResultsDelegate = self; } @end </code></pre> <h2>------</h2> <hr> Here is my Term.m file: <pre><code>// // Term.m // Enayet // // Created by Filip on 12/27/10. // Copyright 2010 __MyCompanyName__. All rights reserved. // #import "Term.h" @implementation Term @synthesize name; - (Term*)initToCall:(NSString*) toSetName { name = toSetName; return self; } - (NSString*)getName { return name; } -(void)dealloc { [name release]; [super dealloc]; } @end </code></pre>
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