this is my code:
array = [[NSMutableArray alloc] init];
NSArray *paths = NSSearchPathForDirectoriesInDomains
(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
//make a file name to write the data to using the
//documents directory:
NSString *fullFileName = [NSString stringWithFormat:#"%#/file", documentsDirectory];
array = [NSKeyedUnarchiver unarchiveObjectWithFile:fullFileName];
What's Wrong in my code?
This is the error
[__NSArrayM count]: message sent to deallocated instance 0xd5864e0
The statement
array = [NSKeyedUnarchiver unarchiveObjectWithFile:fullFileName];
will give you back an autorelease object that will be deallocated at the first appropriate moment. So, when you later access its count method, the object is not there anymore. This is what is causing the crash.
A way to fix this is properly managing your array so that it stays there as long as you need it. If you are using ARC, this could mean managing the object through a strong property; if you are not using ARC, this involves using retain. You do not specify how array is declared so I cannot be more precise.
Since you say that the property is declared as:
#property (nonatomic,retain) NSMutableArray *array
simply doing:
self.array = [NSKeyedUnarchiver unarchiveObjectWithFile:fullFileName];
should fix the problem.
Related
I've been stuck on this for ever and I finally figured it out and now just out of the blue it stopped working again...
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *filePath = [NSString stringWithFormat:#"%#/scoreCards.dgs",documentsDirectory];
NSMutableArray *savedArrayOfScorecards = [[NSMutableArray alloc]init];
savedArrayOfScorecards = [NSMutableArray arrayWithContentsOfFile:filePath];
[savedArrayOfScorecards addObject:currentScoreCard];
[savedArrayOfScorecards writeToFile:filePath atomically:YES];
The file scoreCards.dgs is not even getting created...
What am I doing wrong?
There could be a couple things going wrong here.
1) The kind of data you're storing in the array might not be encodable or archive-able to a file. And the code snippet you included doesn't give a good hint as to what kind of data you're trying to save. If you have custom objects in your array (i.e. things that are not NSString, NSNumber, NSDate, etc.), then that's definitely the problem. There are plenty of questions here on StackOverflow that might help you solve this issue.
2) Your array's filepath could be bogus. For example, you're not checking to see if "documentsDirectory" is nil or valid or writeable.
3) Also possible, but not likely, "savedArrayOfScorecards" might be a nil array. You should do error checking to make sure "savedArrayOfScorecards" was instantiated and that there is more than one object in the array.
Your problem is, that although you create an array, before reading the file it is getting nil-ed on your call to:
savedArrayOfScorecards = [NSMutableArray arrayWithContentsOfFile:filePath];
So, because this savedArrayOfScorecards is now nil, your call to write it to a file is not doing anything.
You should load the array to another variable, and check it being nil, and create the new array only if the one read from the file is nil. Something like this:
NSMutableArray *savedArrayOfScorecards = [NSMutableArray arrayWithContentsOfFile:filePath];
if (!savedArrayOfScorecards) {
savedArrayOfScorecards = [[NSMutableArray alloc]init];
}
Are you sure the file exists when loading it?
savedArrayOfScorecards = [NSMutableArray arrayWithContentsOfFile:filePath];
This line creates a new NSMutableArray from the file. If the file does not exist, it returns nil. writeToFile is then sent to nil and nothing would happen.
Add a check to see if it's nil and create a new array if it is:
NSMutableArray *savedArrayOfScorecards = [NSMutableArray arrayWithContentsOfFile:filePath];
if(savedArrayOfScorecards == nil) savedArrayOfScorecards = [NSMutableArray array];
[savedArrayOfScorecards addObject:currentScoreCard];
[savedArrayOfScorecards writeToFile:filePath atomically:YES];
NSMutableArray is not a property-list-compliant format. You must use an NSArchiver to make it plist compliant.
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *filePath = [NSString stringWithFormat:#"%#/scoreCards.dgs",documentsDirectory];
NSMutableArray *savedArrayOfScorecards = [[NSMutableArray alloc]init];
savedArrayOfScorecards = [NSMutableArray arrayWithContentsOfFile:filePath];
[savedArrayOfScorecards addObject:#"ALLLAALLAAALLA"];
NSMutableData *data = [NSMutableData data];
NSKeyedArchiver *archive = [[NSKeyedArchiver alloc]initForWritingWithMutableData:data];
[archive encodeObject:savedArrayOfScorecards forKey:#"Scorecards"];
[archive finishEncoding];
BOOL result = [data writeToFile:filePath atomically:YES];
NSLog(result ? #"YES" : #"NO");
The correct answers are already here, just adding a better solution:
NSFileManager* fileManager = [NSFileManager defaultManager];
NSMutableArray* array;
if ([fileManager fileExistsAtPath:filePath]) {
array = [NSMutableArray arrayWithContentsOfFile:filePath];
NSAssert(array != nil, #"Invalid data in file.");
}
else {
array = [[NSMutableArray] alloc] init];
}
[array addObject:currentScoreCard];
[array writeToFile:filePath atomically:YES];
My score is displaying just not in the correct order. I've been trying to make a method that uses #selector(compare:) but have had no such luck.
Here's the code I'm working with and I'm wanting to display it from highest to lowest. I'm also wanting to have it so that if you load the app for the first time it creates an empty array so that if the user tries to look at the highscores it doesn't crash the app.
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *scoresListPath = [documentsDirectory stringByAppendingPathComponent:#"scores.plist"];
scoresList = [[NSMutableArray arrayWithContentsOfFile:scoresListPath] retain];
if (scoresList == nil) {
scoresList = [[NSMutableArray array] retain];
}
and
- (void)addHighScore:(float)finalScore {
[scoresList addObject:[NSNumber numberWithFloat:finalScore]];
[scoresList sortUsingSelector:#selector(compare:)];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *scoresListPath = [documentsDirectory stringByAppendingPathComponent:#"scores.plist"];
[scoresList writeToFile:scoresListPath atomically:YES];
}
The reason your code is failing is because arrayWithContentsOfFile: returns an immutable array even though it is called on NSMutableArray. You should make a mutable copy of the array that you read of the file like this,
scoresList = [[NSArray arrayWithContentsOfFile:scoresListPath] mutableCopy];
This will give you an NSMutableArray object which can be added to.
Not sure about lowest but,you can use GKLeaderBoardViewController class for counting Highest Score.For more details I suggested you to read below link.Thanks
http://developer.apple.com/library/ios/#documentation/GameKit/Reference/GKLeaderboardViewController_Ref/Reference/Reference.html
I was trying to use a plist to store an array with the below code:
NSString *name = firstName.text;
NSString *path = [[NSBundle mainBundle] pathForResource:#"Names" ofType:#"plist"];
NSMutableArray *namesArray = [[NSMutableArray alloc] initWithContentsOfFile:path];
[namesArray addObject:name];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
[paths release];
NSString *docDirPath = [documentsDirectory stringByAppendingPathComponent:#"Names.plist"];
[namesArray writeToFile:docDirPath atomically:YES];
namesArray = [[NSMutableArray alloc] initWithContentsOfFile:docDirPath];
This code seems to work. Using NSLog, I have found that after this code executes the plist contains what I want it to, however, my program crashes because it generates an EXC_BAD_ACCESS on a device, and on the simulator it just crashes without an explanation. Does anyone know why that might happen?
NSArray *paths = NSSearchPathForDirectoriesInDomains
(NSDocumentDirectory, NSUserDomainMask, YES); //Auto-released array
NSString *documentsDirectory = [paths objectAtIndex:0];
[paths release]; //Oh noes!
You don't own the reference to paths, so don't release it. Remove [paths release] and I'll bet you're fine. You're crashing because the autorelease pool is releasing paths after you've already done it yourself.
Quoth the guide:
You only release or autorelease objects you own. You take ownership of an object if you create it using a method whose name begins with “alloc” or “new” or contains “copy” ... or if you send it a retain message.
Have you checked, at which place it is giving EXC_BAD_ACCESS error.
In your code there are two wrong things; those are.
The Plist file consists a dictionary not an array, Here in the code you are copying the file data to an array. and saving the array to the plist file.
Second one is you are releasing the "paths" array, with out completion of usage of it. you have to release that array at the end of the statements; like after updating the array to the file.
Regards,
Satya
I've looked through the SDK documentation and through other questions that have been asked, and I am still a little confused on how exactly to do this. I had been previously been working with the following code, though it does not give the desired result of a .plist file. Besides mentioning the IBAction in the header files in this code in the .m file, is there anything else that needs to be added or anothe method I should be taking? Thanks!
My Code:
- (IBAction)fedDog {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent:#"dogsFedDays.plist"];
NSMutableArray *dogsFedSave = [NSMutableArray arrayWithCapacity: 100];
for (int i = 0; i < 100; i++) {
NSDictionary *myDict = [[NSDictionary alloc] initWithObjectsAndKeys:
date[i], #"string",
fed[i], #"Yes",
nil];
[dogsFedSave addObject:myDict];
[myDict release];
}
if (![dogsFedSave writeToFile:path atomically:YES])
NSLog(#"not successful in completing this task");
}
I'm assuming that -writeToFile is returning NO so you're seeing your NSLog statement (correct me if I'm wrong). If that's the case, then the issue must be that some object in either your date array, or fed array is not any of the allowed object types for property lists which includes: NSString, NSData, NSArray, or NSDictionary. NSNulls are not allowed. From the docs for writeToFile:
This method recursively validates that
all the contained objects are property
list objects before writing out the
file, and returns NO if all the
objects are not property list objects,
since the resultant file would not be
a valid property list.
I seem to have a fundamental gap in my memory management understanding. The code below is located within a singleton that gets called multiple times within my app to parse data that is downloaded from the web. For each article I download, I allocate a mutable string, then do tons of parsing, then write the file to the file system for later display in a UIWebView.
But every time I enter this method, I allocate a new "articleString". And I never release this string. I think this is a leak, but if I add a release at the bottom of this method (after the file is written), my app crashes the next time this method is called. I don't understand why it crashes, since another NSMutableString is allocated next time it is called.
UPDATE: I do release articleString in the dealloc method. But it still seems that I should release at the end of this method, since I alloc every time I enter.
UPDATE: articleString is defined as follows in the header:
#property (nonatomic, retain) NSMutableString *articleString;
the parseArticle method below is a placeholder for a series of methods that manipulate articleString.
self.articleString = [[NSMutableString alloc] initWithData:articleData encoding:NSUTF8StringEncoding];
//Parse the article for display
[self parseArticle];
//Write the article string to a file for later display
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent:#"article.html"];
NSLog(#"%#", articleString);
[articleString writeToFile:path atomically:YES];
I like to let properties handle this for me. If the articleString property is set to retain then this is simple.
self.articleString = [[[NSMutableString alloc] initWithData:articleData encoding:NSUTF8StringEncoding] autorelease];
[self doStuff];
Then
- (void)dealloc {
self.articleString = nil;
[super dealloc]
}
article string will get released and properly retain when you set a new one. And it will be cleaned up on dealloc.