EXC_BAD_ACCESS in main( ) - objective-c

I got an EXC_BAD_ACCESS in main(), here is my code:
int main(int argc, char *argv[])
{
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
int retVal = UIApplicationMain(argc, argv, nil, #"TestBedAppDelegate");
[pool release];
return retVal;
}
#interface TestBedAppDelegate : NSObject <UIApplicationDelegate>
#end
#implementation TestBedAppDelegate
- (void)applicationDidFinishLaunching:(UIApplication *)application {
UIWindow *window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:[[TestBedViewController alloc] init]];
[window addSubview:nav.view];
[window makeKeyAndVisible];
}
#end
- (void) action: (id) sender
{
[self highRetainCount];
}
#implementation TestBedViewController
- (void) highRetainCount
{
UIView *view = [[[UIView alloc] init] autorelease];
printf("Count: %d\n", [view retainCount]);
NSArray *array1 = [NSArray arrayWithObject:view];
printf("Count: %d\n", [view retainCount]);
[array1 autorelease]; // If comment this line, everything will be OK
}
#end
The program stopped at main():
int retVal = UIApplicationMain(argc, argv, nil, #"TestBedAppDelegate");
As the comment says, after commenting out [array1 autorelease];, everything was OK.
So here is my question:
EXC_BAD_ACCESS often indicates using an object already released. Clearly there's something to do with [array1 autorelease];, but I can't understand their relationship.
Why stopped at this position -- main() -- instead of somewhere else?
Newbie question :)

arrayWithObject: returns an object you do not own. Therefore it is wrong for you to subsequently send it autorelease.
See the Basic Memory Management Rules, specifically:
You must not relinquish ownership of an object you do not own
and
You own any object you create
You create an object using a method whose name begins with “alloc”, “new”, “copy”, or “mutableCopy” (for example, alloc, newObject, or mutableCopy).
Also, as a more general point, don't use retainCount. Unless you happen to be doing low-level hacking of the runtime or something, you don't need it, and it won't return anything of use to you.

Related

NSTextField doesn't respond to keyboard input

I tried to write a single-window application using Objective-C in OS X 10.8 to test some thing. Everything works fine except that the NSTextField I created does not respond to keyboard input. The code is as follows:
#import <Cocoa/Cocoa.h>
#interface customizedView:NSView
+(customizedView *)aCustomizedView; // changed method name to follow convention
#end
#implementation customizedView
+(customizedView *)aCustomizedView{
customizedView *newView = [[[customizedView alloc] initWithFrame:NSMakeRect(0,0,400,300)] autorelease];
NSTextField *tf = [[[NSTextField alloc] initWithFrame:NSMakeRect(200,150,150,50)] autorelease];
[newView addSubview: tf positioned:NSWindowBelow relativeTo:newView];
return newView;
}
-(void)windowWillClose:(NSNotification *)aNot{
[NSApp terminate:self];
}
#end
void setup(){
NSWindow *aWindow = [[[NSWindow alloc] initWithContentRect:NSMakeRect(0,0,400,300) styleMask:NSTitledWindowMask | NSClosableWindowMask | NSResizableWindowMask backing:2 defer:NO] autorelease];
customizedView *aView = [customizedView aCustomizedView];
[aWindow setContentView:aView];
[aWindow setDelegate:aView];
[aView setNeedsDisplay:YES];
[aWindow makeKeyAndOrderFront:nil];
}
int main(int argc, char **argv){
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSApplication *NSApp = [NSApplication sharedApplication];
setup();
[NSApp run]; [NSApp release]; [pool release];
exit(EXIT_SUCCESS);
}
Compile using
gcc -w filename.m -o tmp -framework Cocoa
Everything works except that I cannot input using keyboard to input into the textfield in my customized NSView. Paste using mouse is okay. So far I still have no ideal why this happens and I give my thanks in advance to all who read this tip sincerely.

NSMutableArray to NSString and Passing NSString to Another View IOS5.1

I have an NSMutableArray of names. I want the pass the data (selected name) inside of NSMutableArray as text to another view's label.
FriendsController.m:
- (void)viewDidLoad {
[super viewDidLoad];
arrayOfNames=[[NSMutableArray alloc] init];
arrayOfIDs=[[NSMutableArray alloc] init];
userName=[[NSString alloc] init];
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
long long fbid = [[arrayOfIDs objectAtIndex:indexPath.row]longLongValue];
NSString *user=[NSString stringWithFormat:#"%llu/picture",fbid];
[facebook requestWithGraphPath:user andDelegate:self];
userName=[NSString stringWithFormat:#"%#",[arrayOfNames objectAtIndex:indexPath.row]];
FriendDetail *profileDetailName = [[FriendDetail alloc] initWithNibName: #"FriendDetail" bundle: nil];
profileDetailName.nameString=userName;
[profileDetailName release];
}
- (void)request:(FBRequest *)request didLoad:(id)result {
if ([result isKindOfClass:[NSData class]]) {
transferImage = [[UIImage alloc] initWithData: result];
FriendDetail *profileDetailPicture = [[FriendDetail alloc] initWithNibName: #"FriendDetail" bundle: nil];
[profileDetailPicture view];
profileDetailPicture.profileImage.image= transferImage;
profileDetailPicture.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
[self presentModalViewController:profileDetailPicture animated:YES];
[profileDetailPicture release];
}
}
In FriendDetail.h
NSString nameString;
IBOutlet UILabel *profileName;
#property (nonatomic, retain) UILabel *profileName;
#property (nonatomic, retain) NSString *nameString;
In FriendDetail.m
- (void)viewDidLoad
{
[super viewDidLoad];
profileName.text=nameString;
}
nameString in second controller(FriendDetail) returns nil. When i set a breakpoint in firstcontroller I see the string inside of nameString is correct but after that it returns to nil somehow.
-----------------------EDIT----------------------------------------
According to answers I have improved my code little bit
FriendsController.h
FriendDetail *friendController;
#property (strong, nonatomic) FriendDetail *friendController;
FriendsController.m
- (void)viewDidLoad
{
[super viewDidLoad];
arrayOfNames=[[NSMutableArray alloc] init];
arrayOfIDs=[[NSMutableArray alloc] init];
arrayOfThumbnails=[[NSMutableArray alloc] init];
userName=[[NSString alloc] init];
friendController= [[FriendDetail alloc] initWithNibName: #"FriendDetail" bundle: nil];
}
-(void)request:(FBRequest *)request didLoad:(id)result{
if ([result isKindOfClass:[NSData class]])
{
transferImage = [[UIImage alloc] initWithData: result];
friendController.nameString=userName;
[friendController view];
friendController.profileImage.image= transferImage;
friendController.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
[self presentModalViewController:friendController animated:YES];
}
//this is how i take facebook friends list
if ([result isKindOfClass:[NSDictionary class]]){
items = [[(NSDictionary *)result objectForKey:#"data"]retain];
for (int i=0; i<[items count]; i++) {
NSDictionary *friend = [items objectAtIndex:i];
long long fbid = [[friend objectForKey:#"id"]longLongValue];
NSString *name = [friend objectForKey:#"name"];
NSLog(#"id: %lld - Name: %#", fbid, name);
[arrayOfNames addObject:[NSString stringWithFormat:#"%#", name]];
[arrayOfIDs addObject:[NSNumber numberWithLongLong:fbid]];
}
}
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
long long fbid = [[arrayOfIDs objectAtIndex:indexPath.row]longLongValue];
NSString *user=[NSString stringWithFormat:#"%llu/picture",fbid];
userName=[NSString stringWithFormat:#"%#",[arrayOfNames objectAtIndex:indexPath.row]];
[facebook requestWithGraphPath:user andDelegate:self];
[username retain]
}
Now when i select row first time it sends name. When i come back to tableview and select another name it shows the old name.
If I delete [username retain] in didSelectRowAtIndexPath: it still sends nil to nameString
when I set break point at didSelectRowAtIndexPath: at line `
userName=[NSString stringWithFormat:#"%#",[arrayOfNames objectAtIndex:indexPath.row]]`
I can see userName = #"Adam Dart" which is correct
in my second breakpoint at line friendController.nameString=userName; I see that nameString =nil and userName = Variable is not CFString
ARC is set to NO
The value is nil because you did not pass the value in request:didLoad: function.
In function didSelectRowAtIndexPath, You create a local instance of another ViewController and set the value of nameString, but you did not present the view and release the ViewController immediately. You actually do nothing in these few lines of code:
FriendDetail *profileDetailName = [[FriendDetail alloc] initWithNibName: #"FriendDetail" bundle: nil];
profileDetailName.nameString = userName;
[profileDetailName release];
In function request:didLoad:, again you create a local instance of another ViewController with image. But this instance is only local to this function, which means no relation to the one created in didSelectRowAtIndexPath.
What you need to do is, remember the name of clicked row first in didSelectRowAtIndexPath, here you dont have to create the ViewController instance. When the request finish, set both the image and name to the controller and then present it. But you should avoid user from clicking different rows at the same time, because you don't know when the request finish.
You have two instances of FriendDetail called profileDetailPicture. Both of theses profileDetailPicture are not the same. So in your didSelectRowAtIndexPath method, the value that you assigned to the nameString will not be visible/available to the nameString of the profileDetailPicture In the request:(FBRequest *)request didLoad method.
Edit for solution:
Create an iVar or property (profileDetailPicture) in the FriendController.
Only do one allocation in the request:(...) method.
Remove the allocation statement in the didSelectRowAtIndexPath.
Any chance it has to do with the fact that you assign to profileDetailName and then immediately release it?
profileDetailName.nameString=userName;
[profileDetailName release];
You have to allocate the "first_controller" in your "second_controller"
to pass objects such as your string. and you would call the nameString differently.
example:
second_controller.h
#import "first_controller.h"
...
#interface second_controller : UIViewController{
first_controller* firstController;
}
second_controller.m
- (void)viewDidLoad {
[super viewDidLoad];
firstController = [[first_controller alloc] init];
profileName.text = firstController.nameString;
}
Which you'll have to init it correctly, because its two views sharing information.

Why do I crash? Dealloc/release + property/retain weirdness

Code in my controller:
CalcBorderBlocks *calcBB = [[CalcBorderBlocks alloc] init];
NSMutableArray *blockArray = [calcBB calc:341241133];
[calcBB release]; // Releases calcBB.
Code in CalcBorderBlocks.h:
#import <Foundation/Foundation.h>
#interface CalcBorderBlocks : NSObject {
#private
NSMutableArray *blockArray_;
}
#property(nonatomic, retain) NSMutableArray *blockArray;
- (NSMutableArray *)calc:(int)blockID;
#end
Code in CalcBorderBlocks.m:
#import "CalcBorderBlocks.h"
#implementation CalcBorderBlocks
#synthesize blockArray = blockArray_;
- (id)init {
self = [super init];
if (self) {
blockArray_ = [[NSMutableArray alloc] init]; // Retain count should be 1
}
return self;
}
- (NSMutableArray *)calc:(int)blockID {
// Do stuff
return self.blockArray;
}
- (void)dealloc {
[blockArray_ release]; // Normal cleanup, yet crashes! Works fine if I comment out this line.
[super dealloc];
}
#end
If you're doing anything with blockArray after this line:
[calcBB release]; // Releases calcBB.
Then that's the cause of the crash.
You're releasing calcBB which in turn releases blockArray in dealloc.
I suspect you need to retain blockArray, process it as required then release it afterwards.
CalcBorderBlocks *calcBB = [[CalcBorderBlocks alloc] init];
NSMutableArray *blockArray = [[calcBB calc:341241133] retain];
[calcBB release]; // Releases calcBB.
// Process blockArray as needed
[blockArray release];
This:
CalcBorderBlocks *calcBB = [[CalcBorderBlocks alloc] init];
NSMutableArray *blockArray = [calcBB calc:341241133];
[calcBB release]; // Releases calcBB.
usually means that blockArray is retained but also autoreleased. If you want to keep it alive, you'll have to retain it yourself, otherwise it will be released by the autorelease pool after a while.
Post the backtrace of the crash. More likely than not, it is because you overreleased something in the array (or the array itself somewhere else.

objective-c threading with NSobject subclass

Im using a threading class (.h/.m below) where the subclass is UIViewcontroller works without any issues.
#interface myFirstClass : UIViewController <MyOperationDelegate>{
However when I use it where the subclass is a NSobject to call a reachability class checking for internet connection, the App crashes when calling performSelectorOnMainThread? I dont understand why, there are no error when I build the App and when it crashes all i get is EXC_BAS_ACCESS. Is it not possible to do this when dealing with an NSObject? Any suggestion will be helpful for me.
#interface AppController : NSObject <MyOperationDelegate>{
myThreading.h
#protocol MyOperationDelegate
#required
-(void) updatedStatus:(NSArray*)items;
-(void) failedStatusWithError:(NSError*)error;
#end
#interface MyOperation : NSObject {
NSObject<MyOperationDelegate> * delegate;
NSOperationQueue *queue;
}
#property (retain) NSObject<MyOperationDelegate> *delegate;
-(void)load: (NSString *)stringUrlPath:(NSString *)functionAction;
#end
myThreading.m
#interface MyOperation (NSObject)
-(void)dispatchLoadingOperation:(NSDictionary *)aParameters;
#end
#implementation MyOperation
#synthesize delegate;
-(id)init
{
if ([super init]!=nil) {
queue = [NSOperationQueue new];
[queue setMaxConcurrentOperationCount:1];
}
return self;
}
-(void)load: (NSString *)stringUrlPath: (NSString *)functionAction {
[self dispatchLoadingOperation:[NSDictionary dictionaryWithObjectsAndKeys:
stringUrlPath, #"urlString", functionAction, #"action", nil]];
}
-(void)dealloc {
[queue cancelAllOperations];
self.delegate = nil;
[super dealloc];
}
-(void)dispatchLoadingOperation:(NSDictionary *)aParameters {
if([aParameters objectForKey:#"action"] == #"getStatus"){
#synchronized(self) {
NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self
selector:#selector(fetchCheckStatus:)
object:aParameters];
[queue addOperation:operation];
[operation release];
}
}
}
-(void) fetchCheckStatus:(NSDictionary *)aParameters
{
NSData* data = [[NSMutableData alloc] initWithContentsOfURL:[NSURL URLWithString:[aParameters objectForKey:#"urlString"]] ];
NSError *error;
NSString *responseString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
if (responseString != nil) {
NSMutableArray *rssItems;
[self.delegate performSelectorOnMainThread:#selector(updatedStatus:) withObject:[NSArray arrayWithObjects:rssItems, nil] waitUntilDone:NO];
} else {
[queue cancelAllOperations];
[self.delegate performSelectorOnMainThread:#selector(failedStatusWithError:) withObject:error waitUntilDone:NO];
}
[responseString autorelease];
[data release];
}
#end
The problem are these lines:
NSMutableArray *rssItems;
[self.delegate performSelectorOnMainThread:#selector(updatedStatus:) withObject:[NSArray arrayWithObjects:rssItems, nil] waitUntilDone:NO];
You declare a variable rssItems but don't set it. It will contain random garbage from the stack which will then be interpreted as a pointer. Maybe sometimes you're lucky and the value is actually a pointer to a living object, but more likely dereferencing it causes your crash.
You need to actually initialize the variable, e.g.:
NSMutableArray *rssItems = nil;
but I guess you really want:
NSMutableArray *rssItems = [NSMutableArray array];

NSCFArray leak in the NSMutablearray allocation

I am getting the leak at this allocation
filteredListContent = [[NSMutableArray alloc] initWithCapacity:[showList count]];
CODE:
-(void)reloadTable
{
EventListAppDelegate *appDelegate;
UIApplication app = [UIApplication sharedApplication];
appDelegate = (EventListAppDelegate *)[app delegate];
contactList = [appDelegate getAllContactsList];
inviteeList = [appDelegate getInviteeListForEvent:event.primaryKey];
if (isInvited == YES)
{
showList = [appDelegate getInviteeListForEvent:event.primaryKey];
}
else
{
showList = [appDelegate getAllContactsList];
}
filteredListContent = [[NSMutableArray alloc] initWithCapacity:
[showList count]];
[filteredListContent addObjectsFromArray: showList];
[self organizeContactItemsIntoIndexes];
self.title = [event.name capitalizedString];
[self getToolbar];
[theTableView reloadData];
}
- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText
{
[filteredListContent removeAllObjects];
ContactDTO *currentElement;
NSRange range;
for (currentElement in showList)
{
range = [currentElement.lastName rangeOfString:searchText
options:NSCaseInsensitiveSearch];
if(range.location == 0)
{
[filteredListContent addObject:currentElement];
}
}
[self organizeContactItemsIntoIndexes];
[theTableView reloadData];
}
- (void)dealloc
{
[filteredListContent release];
[super dealloc];
}
Your code will allocate a new instance of filteredListContent every time reloadTable is called, which will usually happen several times during the lifetime of your application. This causes a leak because the old instances are not released.
The best (and easiest) way to fix it would be to make filteredListContent a retain property:
in your class header:
#property (nonatomic, retain) NSMutableArray * filteredListContent;
in your reloadTable method:
self.filteredListContent = [NSMutableArray arrayWithCapacity:[showList count]];
Note the use of self. in the second code snippet. That syntax informs Cocoa that it should use the property accessor to set the value of filteredListContent, which will then send the appropriate retain and release messages for you.
You've posted three nearly-identical questions pertaining to memory leaks. It might be helpful for you to read through Apple's Memory Management Programming Guide.