NSArray Troubles

[Peak Mobile]

Hi everyone,

I'm having trouble initializing an array, populating a UITextView with an object from the array (all of the objects are NSStrings) and then being able to switch which object is displayed with a next and a previous button. Here is my code:

The header file:

#import <UIKit/UIKit.h>

@interface WordsPage : UIViewController {
    IBOutlet UITextView *wordsText;
    IBOutlet UIButton *prevButton;
    IBOutlet UIButton *nextButton;
    NSArray *WordsArray;
    
}

@property (retain, nonatomic) UITextView *wordsText;
@property (retain, nonatomic) UIButton *prevButton;
@property (retain, nonatomic) UIButton *nextButton;
@property (retain, nonatomic) NSArray *WordsArray;

-(IBAction)nextButton:(id)sender;
-(IBAction)prevButton:(id)sender;
-(void)updateText;

@end

And my implemenation file:

#import "WordsPage.h"

@implementation WordsPage
@synthesize wordsText;
@synthesize prevButton;
@synthesize nextButton;
@synthesize WordsArray;



int num;

NSString *words1 = @"Words string 1";
NSString *words2 = @"Words string 2";
NSString *words3 = @"Words string 3";
NSString *words4 = @"Words string 4";
NSString *words5 = @"Words string 5";
NSString *words6 = @"Words string 6";

//ERROR Initializer element is not a compile-time constant
static NSArray *WordsArray = [[NSArray alloc] initWithObjects:
                        words1,
                        words2,
                        words3,
                        words4,
                        words5,
                        words6, nil];   //ERROR Initializer element is not a constant

    
    
-(IBAction)prevButton:(id)sender {
    num--;
    if (num<0) num=5;
    [self updateText];
    
}


-(IBAction)nextButton:(id)sender {
    num++;
    if (num>5) num=0;
    [self updateText];
    
}

-(void)updateText {
        wordsText.text = [WordsArray objectAtIndex:num];
}

- (void)viewDidLoad {

    
    int num = 0;
    
    wordsText.text = [WordsArray objectAtIndex:num];
    
    self.navigationItem.title=@"Words Page ";
    [super viewDidLoad];
}


-(void)dealloc {
    [wordsText release];
    [favButton release];
    [nonfavButton release];
    [WordsArray release];
    [super dealloc];
}

@end

Any ideas of what I am doing wrong?

Thanks!

-Andrew

[Duncan C]

Originally Posted by Peak Mobile

Hi everyone,

I'm having trouble initializing an array, populating a UITextView with an object from the array (all of the objects are NSStrings) and then being able to switch which object is displayed with a next and a previous button. Here is my code:

The header file:

#import <UIKit/UIKit.h>

@interface WordsPage : UIViewController {
    IBOutlet UITextView *wordsText;
    IBOutlet UIButton *prevButton;
    IBOutlet UIButton *nextButton;
    NSArray *WordsArray;
    
}

@property (retain, nonatomic) UITextView *wordsText;
@property (retain, nonatomic) UIButton *prevButton;
@property (retain, nonatomic) UIButton *nextButton;
@property (retain, nonatomic) NSArray *WordsArray;

-(IBAction)nextButton:(id)sender;
-(IBAction)prevButton:(id)sender;
-(void)updateText;

@end

And my implemenation file:

#import "WordsPage.h"

@implementation WordsPage
@synthesize wordsText;
@synthesize prevButton;
@synthesize nextButton;
@synthesize WordsArray;



int num;

NSString *words1 = @"Words string 1";
NSString *words2 = @"Words string 2";
NSString *words3 = @"Words string 3";
NSString *words4 = @"Words string 4";
NSString *words5 = @"Words string 5";
NSString *words6 = @"Words string 6";

//ERROR Initializer element is not a compile-time constant
static NSArray *WordsArray = [[NSArray alloc] initWithObjects:
                        words1,
                        words2,
                        words3,
                        words4,
                        words5,
                        words6, nil];   //ERROR Initializer element is not a constant

    
    
-(IBAction)prevButton:(id)sender {
    num--;
    if (num<0) num=5;
    [self updateText];
    
}


-(IBAction)nextButton:(id)sender {
    num++;
    if (num>5) num=0;
    [self updateText];
    
}

-(void)updateText {
        wordsText.text = [WordsArray objectAtIndex:num];
}

- (void)viewDidLoad {

    
    int num = 0;
    
    wordsText.text = [WordsArray objectAtIndex:num];
    
    self.navigationItem.title=@"Words Page ";
    [super viewDidLoad];
}


-(void)dealloc {
    [wordsText release];
    [favButton release];
    [nonfavButton release];
    [WordsArray release];
    [super dealloc];
}

@end

Any ideas of what I am doing wrong?

Thanks!

-Andrew

The values assigned to static variables have to be constants.

Make wordsArray a retained property, not a static var, and initialize it in your init method.

use code like this:

self.wordsArray = [NSArray arrayWithObjects: 
  words1,
  words2,
  words3,
  words4,
  words5,
  words6,
  nil];

and make sure to set self.wordsArray to nil in your dealloc method.

[Peak Mobile]

Aren't I retaining the array from the @property line of code in the header file? How do I retain it from the implementation file?

And can you explain the init method? I have not seen that before. Or are you refering to the ViewDidLoad method?

Thanks,

Andrew

[Domele]

1. No, you aren't using your property. You are using whole entirely different variable and to top it off, you made it a constant.

2. The init method he posted does the exact same thing as initWithObjects: except it returns an autoreleased object instead of one with a retain count of 1.

[Peak Mobile]

It took me forever, but I finally got it working! Thank you for your help, guys!