Change button text with random values using Objective-C

Question

I am new to Objective-C and X-Code and basically programming in iOS so this may be a very simple question. Anyway, I'm trying to make a logo quiz wherein the logos and the choices are generated in random order i.e. (Logo 1) --- Choices: A B C D for the first try. Then the next time the user opens the app, Logo 4 appears first with choices A D B C. (I hope that's clear). I've managed to randomly display the logos but can't figure out how to do the same for the choices which would modify the value of 4 buttons below the logo.

From what I've search, you use something like:

 [btnA setTitle:@"answer" forState:UIControlStateNormal];

My problem is, I'm thinking of putting the choices into an array as well so I tried something such as this:

[btnA setTitle:[answerArray objectAtIndex:i] forState:UIControlStateNormal];]

Similar to what I've done for the logos but I'm not getting any values for the button. Is there something I'm missing here? I don't get any errors either. Here's a part of my code that might better explain what I've been trying to do:

NSMutableArray *answerList = [[NSMutableArray alloc] initWithObjects:
                               @"AnswerA",
                               @"AnswerB",
                               @"AnswerC",
                               nil];
answerArray = answerList;
int i = arc4random() % [answerArray count];
[self.btn1 setTitle:[answerArray objectAtIndex:i] forState:UIControlStateNormal];
[self.btn2 setTitle:[answerArray objectAtIndex:i] forState:UIControlStateNormal];
[self.btn3 setTitle:[answerArray objectAtIndex:i] forState:UIControlStateNormal];

answerArray must contain objects of kind NSString or NSMutableString... if this is ok, then kindly post more code — Anoop Vaidya, Jan 18 '13 at 09:33
Thanks for that suggestion. I think that's one of the points where I went wrong, I'll update my post to show more code. — user1597438, Jan 18 '13 at 09:36
when did you init your buttons? from a nib? self.btn1 might be nil when you set the titles — Di Wu, Jan 18 '13 at 09:42
I didn't init the buttons since I didn't there was a need for it. And sorry, I'm not exactly sure what a nib is. Just started coding in Objective-C yesterday. — user1597438, Jan 18 '13 at 09:51
nib is historical name for xib.... and i assume you are familiar with xib.. — Anoop Vaidya, Jan 18 '13 at 09:59

score 1 · Answer 1 · edited May 23 '17 at 12:18

1

Just Shuffle your buttonTitleArray which is MutableArray without repeating any same logo quiz using this link.

Also Shuffle logo quiz's choice to make it interactive with above link.

edited May 23 '17 at 12:18

Community

1
1

answered Jan 18 '13 at 09:42

Paresh Navadiya

38,095
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I don't understand the idea of shuffling mutable arrays yet but I'll try this one once I understand how it works. Thanks for the answer. – user1597438 Jan 18 '13 at 09:52

score 1 · Accepted Answer · answered Jan 18 '13 at 09:47

1

See following code - it can generate random title from set of 100:

-(int)getRandomNumber:(int)fromVal to:(int)toVal {
    return (int)fromVal + arc4random() % (toVal-fromVal+1);
}

-(void) setButtonTitle
{
    NSArray * buttonTitleArray = [NSArray arrayWithObjects:@"title1", @"title2",... @"title100", nil};
    int x = [getRandomNumber :0 :100];
    NSString * title = [buttonTitleArray objectAtIndex:x];
    [button setTitle:title :forState:UIControlStateNormal];
}

answered Jan 18 '13 at 09:47

Nirav Bhatt

6,940
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what if random number from 0 to 100 is greater than buttonTitleArray's count? – Paresh Navadiya Jan 18 '13 at 10:00
change argument values to getRandomNumber. – Nirav Bhatt Jan 18 '13 at 10:33
I tried this solution and I got an error around int x = [getRandomNumber :0 :100];. It said that getRandomNumber is undeclared. I'm pretty sure I added -(int)getRandomNumber:(int)fromVal to:(int)toVal in the .h file so I'm not exactly sure what I'm missing here. – user1597438 Jan 21 '13 at 01:08
Actually, never mind. I just figured it out, I had an image over the button so obviously the texts won't appear. I just changed into into background. (I feel like shooting myself for that.) Thank you again – user1597438 Jan 21 '13 at 02:33

Change button text with random values using Objective-C

2 Answers2