Trouble accessing objects in NSArray using randNum - iphone

Question

I need to access an NSArray and get a value from it with:
-(IBAction) randClicked:(id)sender
{
int randNum;
//when user clicks the button
//create random number, 1 - 32
randNum = arc4random() %32;
As you see, I can display my random number here:
///using this code for testing random number when button is clicked
NSString *randValText = [[NSString alloc]initWithFormat:#"%d", randNum];
//Output random number to label
labelRandText.text = randValText;
//Call method seeImage with SEL methodSelector
SEL methodSelector = #selector(seeImage);
///set image opacity to 0
wisdomView.alpha = 0.0;
//Use NSTimer to call method
[NSTimer scheduledTimerWithTimeInterval:0 target:self selector:methodSelector userInfo:nil repeats:NO];
[randValText release];
}
But now, I need to compare the value of randNum and access an NSArray of images for it's position in the array so I can display an image in an UIImageView.
Having a difficult time trying to figure this one out. All help is greatly appreciated. Thank you for your time.
Here is the current code that I have implemented with help from Josh as of 11:13pm 7/6/2001. I think I almost have it...but something I'm doing is not working. I keep getting the warning "Method '-objectAtIndex not found (return type defaults to 'id')
//Call method seeImage with SEL methodSelector
SEL methodSelector = #selector(seeImage);
//Use NSTimer to call method
[NSTimer scheduledTimerWithTimeInterval:0 target:self selector:methodSelector userInfo:[NSNumber numberWithInt:randNum] repeats:NO];
[randValText release];
}
////This is the method to make the graphic choosen by randNum to display at the top of the screen
-(IBAction) seeImage: (NSTimer *)tim
{
CGContextRef imageContext = UIGraphicsGetCurrentContext();
int randNum = [(NSNumber *)[tim userInfo] intValue];
UIImage *imgToDisplay = [wisdomView objectAtindex:randNum];
wisdomView.image = imgToDisplay;
wisdomView.animationImages = [NSArray arrayWithObjects:
[UIImage imageNamed:#"0.png"],
[UIImage imageNamed:#"1.png"],
[UIImage imageNamed:#"2.png"],
[UIImage imageNamed:#"3.png"],
[UIImage imageNamed:#"4.png"],
[UIImage imageNamed:#"5.png"],
[UIImage imageNamed:#"6.png"],
[UIImage imageNamed:#"7.png"],
[UIImage imageNamed:#"8.png"],
[UIImage imageNamed:#"9.png"],
[UIImage imageNamed:#"10.png"],
[UIImage imageNamed:#"11.png"],
[UIImage imageNamed:#"12.png"],
[UIImage imageNamed:#"13.png"],
[UIImage imageNamed:#"14.png"],
[UIImage imageNamed:#"15.png"],
[UIImage imageNamed:#"16.png"],
[UIImage imageNamed:#"17.png"],
[UIImage imageNamed:#"18.png"],
[UIImage imageNamed:#"19.png"],
[UIImage imageNamed:#"20.png"],
[UIImage imageNamed:#"21.png"],
[UIImage imageNamed:#"22.png"],
[UIImage imageNamed:#"23.png"],
[UIImage imageNamed:#"24.png"],
[UIImage imageNamed:#"25.png"],
[UIImage imageNamed:#"26.png"],
[UIImage imageNamed:#"27.png"],
[UIImage imageNamed:#"28.png"],
[UIImage imageNamed:#"29.png"],
[UIImage imageNamed:#"30.png"],
[UIImage imageNamed:#"31.png"],nil];
wisdomView.alpha = 0;
[UIView beginAnimations:nil context:imageContext];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
[UIView setAnimationDuration:4];
[UIView setAnimationDelegate:self];
wisdomView.alpha = 1;
[UIView commitAnimations];
SEL methodSelector = #selector(hideImage);
[NSTimer scheduledTimerWithTimeInterval:4 target:self selector:methodSelector userInfo:nil repeats:NO];
}
I appreciate the help. Thank you for your time.
Here is the changed code that still doesn't work....I'm not understanding something. 1:19PM 7/7/2011
-(IBAction) seeImage:(NSTimer *)tim
{
NSArray *wisdom;
wisdom = [[NSArray alloc] initWithObjects:
[UIImage imageNamed:#"0.png"],
[UIImage imageNamed:#"1.png"],
[UIImage imageNamed:#"2.png"],
[UIImage imageNamed:#"3.png"],
[UIImage imageNamed:#"4.png"],
[UIImage imageNamed:#"5.png"],
[UIImage imageNamed:#"6.png"],
[UIImage imageNamed:#"7.png"],
[UIImage imageNamed:#"8.png"],
[UIImage imageNamed:#"9.png"],
[UIImage imageNamed:#"10.png"],
[UIImage imageNamed:#"11.png"],
[UIImage imageNamed:#"12.png"],
[UIImage imageNamed:#"13.png"],
[UIImage imageNamed:#"14.png"],
[UIImage imageNamed:#"15.png"],
[UIImage imageNamed:#"16.png"],
[UIImage imageNamed:#"17.png"],
[UIImage imageNamed:#"18.png"],
[UIImage imageNamed:#"19.png"],
[UIImage imageNamed:#"20.png"],
[UIImage imageNamed:#"21.png"],
[UIImage imageNamed:#"22.png"],
[UIImage imageNamed:#"23.png"],
[UIImage imageNamed:#"24.png"],
[UIImage imageNamed:#"25.png"],
[UIImage imageNamed:#"26.png"],
[UIImage imageNamed:#"27.png"],
[UIImage imageNamed:#"28.png"],
[UIImage imageNamed:#"29.png"],
[UIImage imageNamed:#"30.png"],
[UIImage imageNamed:#"31.png"],nil];
int randNum = [(NSNumber *)[tim userInfo] intValue];
CGContextRef imageContext = UIGraphicsGetCurrentContext();
UIImage *imgToDisplay = [wisdom objectAtIndex:randNum];
wisdomView.image = imgToDisplay;
Still getting the Method '-objectAtIndex:' not found warning and now '' may not respond to '' 'NSArray' may not respond to '-objectAtIndex'. Arrrrgggg.
Thank you for your time.

Answer 1

Tuck the generated number into the timer's user info slot:
[NSTimer scheduledTimerWithTimeInterval:0
target:self
selector:#selector(seeImage:)
userInfo:[NSNumber numberWithInt:randNum]
repeats:NO];
and then get it back out in the timer's method. By the way, timer methods are supposed to have one parameter.* The timer passes itself to the method for just such a case as this, i.e., when you need to send some info along to be used when it fires.
- (void) seeImage: (NSTimer *)tim {
// Retrieve the NSNumber, using a cast because userInfo returns id
int randNum = [(NSNumber *)[tim userInfo] intValue];
NSImage * imgToDisplay = [arrayOfImgs objectAtIndex:randNum];
// and so on...
}
*Although they do work with any number of parameters, including 0.

Answer 2

Try:
[imageArray objectAtIndex:randNum]
EDIT: based on the additional info in the comments, I think #Josh Caswell's response better answers the question.

Answer 3

//create random number, 1 - 32
randNum = arc4random() %32;
that would give you 0 - 31. check your array bounds.

Answer 4

I fixed it! Thanks Josh for the assist!
-(IBAction) seeImage
{
int randNum;
//when user clicks the button
//create random number, 0 - 31
randNum = arc4random() %32;
NSString *randValText = [[NSString alloc]initWithFormat:#"%d", randNum];
//Output random number to label - testing code
//labelRandText.text = randValText;
///set image opacity to 0
wisdomView.alpha = 0.0;
wisdom = [[NSArray alloc] initWithObjects:
[UIImage imageNamed:#"0.png"],
[UIImage imageNamed:#"1.png"],
[UIImage imageNamed:#"2.png"],
[UIImage imageNamed:#"3.png"],
[UIImage imageNamed:#"4.png"],
[UIImage imageNamed:#"5.png"],
[UIImage imageNamed:#"6.png"],
[UIImage imageNamed:#"7.png"],
[UIImage imageNamed:#"8.png"],
[UIImage imageNamed:#"9.png"],
[UIImage imageNamed:#"10.png"],
[UIImage imageNamed:#"11.png"],
[UIImage imageNamed:#"12.png"],
[UIImage imageNamed:#"13.png"],
[UIImage imageNamed:#"14.png"],
[UIImage imageNamed:#"15.png"],
[UIImage imageNamed:#"16.png"],
[UIImage imageNamed:#"17.png"],
[UIImage imageNamed:#"18.png"],
[UIImage imageNamed:#"19.png"],
[UIImage imageNamed:#"20.png"],
[UIImage imageNamed:#"21.png"],
[UIImage imageNamed:#"22.png"],
[UIImage imageNamed:#"23.png"],
[UIImage imageNamed:#"24.png"],
[UIImage imageNamed:#"25.png"],
[UIImage imageNamed:#"26.png"],
[UIImage imageNamed:#"27.png"],
[UIImage imageNamed:#"28.png"],
[UIImage imageNamed:#"29.png"],
[UIImage imageNamed:#"30.png"],
[UIImage imageNamed:#"31.png"],nil];
CGContextRef imageContext = UIGraphicsGetCurrentContext();
//pick image randNum index position
wisdomView.image = [wisdom objectAtIndex:randNum];
wisdomView.alpha = 0.0;
[UIView beginAnimations:nil context:imageContext];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
[UIView setAnimationDuration:4];
[UIView setAnimationDelegate:self];
wisdomView.alpha = 1;
[UIView commitAnimations];
SEL methodSelector = #selector(hideImage);
[NSTimer scheduledTimerWithTimeInterval:4 target:self selector:methodSelector userInfo:nil repeats:NO];
[randValText release];
}
Thank you for your time!