Mutable arrays

[KyleTomson]

I thought I would run this by everybody, it is driving me nuts. This shouldn't be so hard, but I feel like I'm missing something simple: Here is my code:

//temp array to hold file paths
NSMutableArray *slideShowFilesTemp = [NSMutableArray arrayWithCapacity:200];

// (I have tried to initialize slideShowFilesTemp this way too)
//NSMutableArray *slideShowFilesTemp;
//slideShowFilesTemp = [[NSMutableArray alloc] init];

//Audioclip file name
NSString *recorderFilePath;
recorderFilePath = [[NSString stringWithFormat:@"%@/%@.caf", DOCUMENTS_FOLDER, questionCorrectAnswerAudioFileName] retain];

//get image path
NSString *imageSelectionName;
imageSelectionName = [sentenceArray objectAtIndex:imageLocationPointer];
NSBundle *bundle3 = [NSBundle mainBundle];
NSString *imagePath1 = [bundle3 pathForResource@"%@", imageSelectionName) ofType:@"png"];

[slideShowFilesTemp addObject:recorderFilePath];
[slideShowFilesTemp addObject:imagePath1];

[self.slideShowFiles addObjectsFromArray:slideShowFilesTemp];

slideShowFiles is a mutable array and has accessor methods. What I am trying to do is keep track of the recorded filepath and the associated image and put them into a MutableArray for access later. This code is in a -IBAction routine that is run when you hit a button.

If I look at what goes into slideShowFilesTemp, it is exactly as I want it. However, when I do a NSLog of the slideShowFiles Mutable array, it comes back as a nil.

If I use the following code: "self.slideShowFiles = slideShowFilesTemp;", then slideShowFiles has exactly the same objects as slideShowFilesTemp, however it just overwrites whatever was in slideShowFiles (as I would expect). I want to add what it in slideShowFilesTemp to the back of slideShowFiles.

Am I not initializing slideShowFilesTemp correctly? I have tried it two ways as shown above. Any suggestions or pointers would be appreciated.

Kyle

[smasher]

Where do you set slideShowFiles? If slideShowFiles is nil then this line:

[self.slideShowFiles addObjectsFromArray:slideShowFilesTemp];

is the same as calling

[nil addObjectsFromArray:slideShowFilesTemp];

Which has no effect. I'm guessing that you need to set slideshowfiles somewhere, like

self.slideShowFiles = [NSMutableArray array];

[KyleTomson]

Originally Posted by smasher

Where do you set slideShowFiles? If slideShowFiles is nil then this line:

[self.slideShowFiles addObjectsFromArray:slideShowFilesTemp];

is the same as calling

[nil addObjectsFromArray:slideShowFilesTemp];

Which has no effect. I'm guessing that you need to set slideshowfiles somewhere, like

self.slideShowFiles = [NSMutableArray array];

I set slideShowArrays in the .h file. I declare it as a NSMutable array and set its property and then synethisize it in the .m file. All pretty standard stuff. I didn't think I would have to set it as a NSMutableArray again. I will give it a try.

This may seem like a dumb question, but if I declare slideShowFiles in my .h file and then synthesize accessor methods, why do I have to set it again?

Just trying to understand what is going on. I really appreciate the help!!

[thomashw]

Declaring it in your header file doesn't initialize it. Setting its property doesn't either. You need to allocate and initialize it in your code somewhere (in your init methods).

Just to give it a quick try, you could put this at the top of your code:

if( slideShowFiles == nil )
  slideShowFiles = [[NSMutableArray alloc] init];

[KyleTomson]

Originally Posted by thomashw

Declaring it in your header file doesn't initialize it. Setting its property doesn't either. You need to allocate and initialize it in your code somewhere (in your init methods).

Just to give it a quick try, you could put this at the top of your code:

if( slideShowFiles == nil )
  slideShowFiles = [[NSMutableArray alloc] init];

Thanks. I'll give that a try tonight and post back.

[KyleTomson]

Originally Posted by KyleTomson

Thanks. I'll give that a try tonight and post back.

Worked like a champ. Thanks for the help.

[thomashw]

Originally Posted by KyleTomson

Worked like a champ. Thanks for the help.

No problem. But make sure you're doing the initializing in your init methods. You don't want to have uninitialized instance variables after an instance of the class has been initialized.