NSString ARRAY crashing..

[vogueestylee]

hi there, I have a code

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    page = 0;
    NSString *filePath = [[NSBundle mainBundle] pathForResource:@"text" ofType:@"txt"];
    
    NSError *error;
	NSString* content = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:&error];
	allLines = [content componentsSeparatedByString: @"\n"];
	NSString *myText = [allLines objectAtIndex:page];
    
    
    textField.text = myText;
  
}

-(IBAction)next:(id)sender{
    page++;
    textField.text = [allLines objectAtIndex:page];

}

it is running ok but when click on the next button it crash.. the allLines NSArrazy is "global" defined in .h file.. so what is wrong..? thanx for advices...

[Duncan C]

Originally Posted by vogueestylee

hi there, I have a code

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    page = 0;
    NSString *filePath = [[NSBundle mainBundle] pathForResource:@"text" ofType:@"txt"];
    
    NSError *error;
	NSString* content = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:&error];
	allLines = [content componentsSeparatedByString: @"\n"];
	NSString *myText = [allLines objectAtIndex:page];
    
    
    textField.text = myText;
  
}

-(IBAction)next:(id)sender{
    page++;
    textField.text = [allLines objectAtIndex:page];

}

it is running ok but when click on the next button it crash.. the allLines NSArrazy is "global" defined in .h file.. so what is wrong..? thanx for advices...

You need to read up on Cocoa memory management.

the method componentsSeparatedByString returns an autoreleased array. An autoreleased object is one that is temporary, and will go away if nobody retains it (or takes ownership of it.)

The cleanest way to fix your code is to change allLines to a retained property by adding this line to your header:

@property (nonatomic, retain) NSArray *allLines;

and adding

@synthesize allLines;

to your .m file.

Then, when you assign a value to allLines, use "property notation":

	self.allLines = [content componentsSeparatedByString: @"\n"];

By saying "self.allLines" you use the setter, which retains the object for you.

Then, in your dealloc method, add the line

self.allLines = nil;

That triggers the setter to release any old value stored in allLines before your object gets deallocated.

[vogueestylee]

Duncan C - your answer is simply PRO! thank you!

just for the future - how to get a number of lines in NSArray? some integer number how many lines of text are there..?

this is working for me: NSLog(@"%@", allLines);
but how to make a sum of objects?

[apatsufas]

Take a look at the NSArray documentation here

You will see that NSArray has a method count which does what you want.

[vogueestylee]

apatsufas - nice page, I got it, for others:

int mcount =[allLines count];
    
    NSLog (@"array = %i", mcount);

[Duncan C]

Originally Posted by vogueestylee

apatsufas - nice page, I got it, for others:

int mcount =[allLines count];
    
    NSLog (@"array = %i", mcount);

Nice page?

That is the online version of the Xcode documentation. There is a full set of documentation that covers all this sort of thing built into Xcode.

Using the Xcode help system to search for documents on different APIs:

Pull down the help menu and select "Documentation and API reference"

Tap on the magnifying glass in the upper left corner, by the input box, and select "show find options" if it isn't active already.

Make the following change to the find options:

• Under "Match type", select "contains". That lets you search for partial names. It's slower, but much more useful. You can type part of a method or class name and Xcode will find it.
• Under doc sets, select the version of iOS you are using for development (iOS 5 perhaps) This narrows the search to the current SDK version, speeds up searching, and avoids duplicate search results.
• Under Languages, select "C" and "Objective C". You need C because some of the Core Foundation frameworks are C. You want to turn off Java and JavaScript so your search results aren't cluttered with things you don't care about.

Now type in "NSArray" into the search field. The list of matches will be shown on the left side. You should see an entry under "Reference" for NSArray. Select it to open the NSArray class reference.