Random presentation of images from plist.

Question

Hello all, my name is Merlin and of course... Im new to this! LOL Ive been teaching myself Obj-C and Cocoa for the better part of 5 months now, and I have to say... I found my path. I absolutely love it and cant wait till I feel more comfortable with the methodology. But enough about me!
Im working on a Q&A based app. To get the UI to look EXACTLY the way I wanted it to, I designed all of the questions in Photoshop. These questions range in topic but normally ask you to tap on something specific in the image. Picture an image with a bunch of dogs and the prompt "tap the boxer..."
I then have 2 custom buttons in IB, one covers the entire screen name "incorrectButton" and another named "correctButton" placed over the spot in the image that is the "correct" location.
I have a HomePageViewController with a start button that loads Question1ViewController with the previously mentioned background UIImageView. Im using presentModalVC to load the question image with a nice UIModalTransCrossDissolve.
Question1ViewController...
"Tap on the boxer"...
User taps incorrect location is sent to my IncorrectResponseViewController which states "Sorry, try again" and pops automatically after a 2 second delay.
User taps correct location is sent to my CorrectResponseViewController which states "That is correct!" and unhides a nextButton. Pressing it implements nextButtonPressed which takes you to Question2ViewController (again by presenting it Modally). Question2ViewController then had a nib with question2.png loaded as the background and a new button layout to correspond to the new "correct" location.
Since the method to call this "next" question is "nextButtonPressed", I soon realized I would never be able to get past Question2 unless I created some kind of loop and store the questions in a plist or Core Data.
This is where I started to investigate loading all of my question images (or just their file names as an NSString) into a plist and using the same nib to present them all. I figured I could also store the "correctButton" coordinates as a Dictionary in that plist and call those in a setFrame method when I want to present the next question.
So I have my plist built and I think it's correct...
[TIMG]http://img.photobucket.com/albums/v686/FJMerlin/Screenshot2010-09-14at20550PM.pn g[/TIMG]
I also created a Constants file with the following keys...
#define BACKGROUNDIMAGE_KEY @"backgroundImage"
#define CORRECTBUTTONLOCATION_KEY @"correctButtonLocation"
#define XBUTTONLOC_KEY @"x"
#define YBUTTONLOC_KEY @"y"
#define WBUTTONLOC_KEY @"w"
#define HBUTTONLOC_KEY @"h"
So this is where my noobism shines through. Im having one **** of a time getting the values out of this plist and onto the screen. What I would like to do is load all (100 as of now) the questions into this plist. Then present the QuestionsViewController and have it randomly present the question Images. Upon selecting the correct location, modally present the CorrectResponseViewController with the nextButton, and have the nextButtonPressed method return you to QuestionsViewController with a new question and button layout. As of now, Im mostly concerned with getting anything out of the plist to work before I worry about randomizing the questions.
Ive attempted to call these values a few different ways.
.h
@interface Q1ViewController : UIViewController {
IBOutlet UIImageView *backgroundImage;
IBOutlet UIButton *backButton;
IBOutlet UIButton *correctButton;
IBOutlet UIButton *incorrectButton;
IBOutlet UIButton *nextButton;
NSMutableArray *questions;
NSMutableArray *buttonCorridinates;
@property (nonatomic, retain) IBOutlet UIImageView *backgroundImage;
@property (nonatomic, retain) IBOutlet UIButton *backButton;
@property (nonatomic, retain) IBOutlet UIButton *nextButton;
@property (nonatomic, retain) IBOutlet UIButton *correctButton;
@property (nonatomic, retain) IBOutlet UIButton *incorrectButton;
@property (nonatomic, retain) NSMutableArray *questions;
@property (nonatomic, retain) NSMutableArray *buttonCorridinates;
- (IBAction) backButtonPressed:(id) sender;
- (IBAction) nextButtonPressed:(id) sender;
- (IBAction) correctButtonPressed:(id) sender;
- (IBAction) incorrectButtonPressed:(id) sender;
@end
.m
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
[super viewDidLoad];
backButton.hidden = YES;
nextButton.hidden = YES;
NSString *path = [[NSBundle mainBundle] pathForResource:@"Questions" ofType:@"plist"];
NSMutableArray* tmpArray = [[NSMutableArray alloc] initWithContentsOfFile:path];
self.questions = tmpArray;
[tmpArray release];
UIImage *tmpImage = [UIImage objectForKey:BACKGROUNDIMAGE_KEY];
[backgroundImage setImage: tmpImage];
[correctButton setFrame:CGRectMake(20.0f,226.0f,192.0f,37.0f)];
[tmpImage release];
NSString *correctButtonLoc = [[NSString alloc] intValue:CORRECTBUTTONLOCATION_KEY];
[correctButton setFrame:CGRectMake(@"%@"),correctButtonLoc];
//or this.... LOL
UIImageView *tmpImage = [[UIImageView alloc] initWithImage:@"%@", BACKGROUNDIMAGE_KEY];
[backgroundImage setImage:tmpImage];
NSString *xButtonLoc = [[NSString intValue[questions objectForKey:XBUTTONLOC_KEY]];
NSString *yButtonLoc = [[NSString intValue[questions objectForKey:YBUTTONLOC_KEY];
NSString *wButtonLoc = [[NSString intValue[questions objectForKey:WBUTTONLOC_KEY];
NSString *hButtonLoc = [[NSString intValue[questions objectForKey:HBUTTONLOC_KEY];
[correctButton setFrame:CGRectMake(@"%@","%@","%@","%@") xButtonLoc, yButtonLoc, wButtonLoc, hButtonLoc];
I feel like I know what to do, I just dont know how to do it. I have the image paths stored in the plist, so I obviously need to call those paths then convert them to the actual image, am I on the right track in that thinking?
For the coordinates, I also have those stored as strings. So Im sure the same holds true. Need to convert those to ints to set my frame. But again, no matter how many time I read through the string formatting guide, I still cant seem to luck into this one.
Once I have this figured out. Ill want to have something very similar to the randomizing plist code from James' FlashCard app which I found in another thread. http://discussions.apple.com/thread.jspa?threadID=2542025
RayNewbie was kind enough to point me in the right direction to start my own thread so here I am!
I hope this isnt to long winded. I wanted to be detailed. Thanks in advance for any guidance.

Answer 1

ok, been at it for half the day already and cant seem to get the shuffleArray method to work with my code. I did tweak some things to make it more similar to the construct of James' FlashCard app.
I did away with my Correct and IncorrectViewControllers. I changed the methods for pressing those buttons to simply change the background image to the appropriate response as well as unhide the next and back buttons to allow these controls to reside in the same VC. Here is how I have it now...
@implementation QuestionsViewController
@synthesize backgroundImage;
@synthesize backButton;
@synthesize nextButton;
@synthesize correctButton;
@synthesize incorrectButton;
@synthesize questions;
@synthesize counter;
- (void)dealloc {
     [backgroundImage release];
     [backButton release];
     [nextButton release];
     [correctButton release];
     [incorrectButton release];
     [questions release];
     [super dealloc];
-(void) viewWillAppear:(BOOL)animated {
     [super viewWillAppear:animated];
     nextButton.hidden = YES;
     backButton.hidden = YES;
- (void) enableButton {
     int count = [questions count];
     nextButton.enabled = counter < count - 1 ? YES : NO;
     backButton.enabled = counter > 0 ? YES : NO;
// The designated initializer.  Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if ((self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil])) {
        // Custom initialization
    return self;
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
     [super viewDidLoad];
     NSString *path = [[NSBundle mainBundle] pathForResource:@"Questions" ofType:@"plist"];
     NSLog(@"%s: path=%@", __func__, path);
     NSMutableArray* tmpArray = [[NSMutableArray alloc]initWithContentsOfFile:path];
     self.questions = tmpArray;
     [tmpArray release];
     [self reset];     
- (void)shuffleArray:(NSMutableArray*)array {
     int total = [array count];
     if (total <= 1)
          return;
     NSMutableArray *poolArray = [[NSMutableArray alloc] initWithArray:array];
     [array removeAllObjects];
     for (int i = 0; i < total; i++) {
          int index = random() % [poolArray count];
          [array addObject:[poolArray objectAtIndex:index]];
          [poolArray removeObjectAtIndex:index];
- (IBAction)reset {
     srandomdev();
     counter = 0;
     [self shuffleArray:questions];
     if ([questions count]) {
          NSDictionary *Question = [questions objectAtIndex:counter];
          NSString *imageFileName = [Question objectForKey:@"backgroundImage"];
          UIImage *bkgdImage = [UIImage imageNamed:imageFileName];
          [backgroundImage setImage:bkgdImage];
          NSDictionary *correctPts = [Question objectForKey:@"correctButtonLocation"];
          CGRect correctRect = CGRectMake(
                                                  [[correctPts objectForKey:@"x"] doubleValue],
                                                  [[correctPts objectForKey:@"y"] doubleValue],
                                                  [[correctPts objectForKey:@"w"] doubleValue],
                                                  [[correctPts objectForKey:@"h"] doubleValue]
          [correctButton setFrame:correctRect];
     } else {
          [backgroundImage setImage:nil];     
     [self enableButton];
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
     // Return YES for supported orientations
     return (interfaceOrientation == UIInterfaceOrientationLandscapeRight);
- (IBAction) correctButtonPressed:(id) sender {
     NSLog(@"correct button pressed");
     nextButton.hidden = NO;
     backButton.hidden = NO;
     UIImage *correctImage = [UIImage imageNamed:@"thatIsCorrect.png"];
     [backgroundImage setImage:correctImage];
     [correctImage release];
- (IBAction) nextButtonPressed:(id)sender {
     NSLog(@"Next button pressed");
     int count = [questions count];
     if (counter < count - 1) {
          NSDictionary *nextItem = [self.questions objectAtIndex:++counter];
          NSString *imageFileName = [nextItem objectForKey:@"backgroundImage"];
          UIImage *bkgdImage = [UIImage imageNamed:imageFileName];
          [backgroundImage setImage:bkgdImage];
          NSDictionary *correctPts = [nextItem objectForKey:@"correctButtonLocation"];
          CGRect correctRect = CGRectMake(
                                                  [[correctPts objectForKey:@"x"] doubleValue],
                                                  [[correctPts objectForKey:@"y"] doubleValue],
                                                  [[correctPts objectForKey:@"w"] doubleValue],
                                                  [[correctPts objectForKey:@"h"] doubleValue]
          [correctButton setFrame:correctRect];
     [self enableButton];
- (IBAction) incorrectButtonPressed:(id) sender {
     NSLog(@"incorrect button pressed");
     IncorrectResponseViewController *incorrectResponseViewController = [[IncorrectResponseViewController alloc] initWithNibName:@"IncorrectResponseViewController" bundle:nil];
     incorrectResponseViewController.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
     [self presentModalViewController:incorrectResponseViewController animated:YES];
     [incorrectResponseViewController release];
- (IBAction) backButtonPressed:(id) sender {
     NSLog(@"Back button pressed");
     if (counter > 0) {
          NSDictionary *nextItem = [self.questions objectAtIndex:--counter];
          NSString *imageFileName = [nextItem objectForKey:@"backgroundImage"];
          UIImage *bkgdImage = [UIImage imageNamed:imageFileName];
          [backgroundImage setImage:bkgdImage];
          NSDictionary *correctPts = [nextItem objectForKey:@"correctButtonLocation"];
          CGRect correctRect = CGRectMake(
                                                  [[correctPts objectForKey:@"x"] doubleValue],
                                                  [[correctPts objectForKey:@"y"] doubleValue],
                                                  [[correctPts objectForKey:@"w"] doubleValue],
                                                  [[correctPts objectForKey:@"h"] doubleValue]
          //NSLog(@"Question %d:\n\timageFileName=%@\n\tcorrectRect=%@", count++, imageFileName, NSStringFromCGRect(correctRect));
          [correctButton setFrame:correctRect];
     [self enableButton];     
- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
    // Release any cached data, images, etc that aren't in use.
- (void)viewDidUnload {
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
@end
The only issue I was having was with "counter" which I see in James' .m file but I wasnt sure what the ivar was. So I used your recommendation Ray and searched all his posts here on the forum and found that it was an fact an int. Now it appears everything is actually working! I just need to tweak the UI to hide and unhide my back and next buttons consistently but so far this is exactly what I was looking for.
Next up I have to figure out how to convert the coordinates to landscape so my correctButton lands up in the right spot and of course... score keeping! LOL
Thanks again Ray!