Question

I have a problem that has been stumping me for a while, I wrote a new version of the program and got the exact same bug.

When the following runs, I should be getting a nicely sectioned table view like,
1964
-Sam
-Ham
1965
-Nim Chimpsky
1980
-George
1985
-Bubbles

Instead I get
1964
-Sam
-Ham
1985
-Sam
1980
-Sam

Does anyone have any hints as to what I’m doing wrong?

My source code is below:

#import <UIKit/UIKit.h>


#pragma mark Monkey Object definition
@interface Monkey : NSObject {
    NSString *monkeyName; 
    NSString *monkeyBirthYear;
}

@property (copy) NSString *monkeyName; 
@property (copy) NSString *monkeyBirthYear; 

-(id)initWithMonkeyName:(NSString*)MN monkeyBirthYear:(NSString *)MBY; 


@end 

@implementation Monkey

@synthesize  monkeyName; 
@synthesize monkeyBirthYear; 

-(id)initWithMonkeyName:(NSString *)MN monkeyBirthYear:(NSString *)MBY; 
{
    if ((self =[super init])) {
        monkeyName = [MN copy]; 
        monkeyBirthYear = [MBY copy]; 

    }
    return self; 
}


@end

@interface ViewController : UITableViewController
{
    NSMutableArray *barrel; 
    NSMutableArray *monkeyBirthdayIndex; 

}
@end

@implementation ViewController





#pragma mark UITableView 
- (NSString *)tableView:(UITableView *)aTableView titleForHeaderInSection:(NSInteger)section
{
    return [monkeyBirthdayIndex objectAtIndex:section];
}


-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return [monkeyBirthdayIndex count]; 
}

- (UITableViewCell *)tableView:(UITableView *)theTableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {


    UITableViewCellStyle style = UITableViewCellStyleDefault; 
    UITableViewCell *cell = [theTableView dequeueReusableCellWithIdentifier:@"Cell"]; 
    if(!cell) 
        cell = [[UITableViewCell alloc] initWithStyle:style reuseIdentifier:@"Cell"]; 

    Monkey *m = [barrel objectAtIndex:[indexPath row]]; 

    cell.textLabel.text = [m monkeyName]; 

    return cell; 
}


- (NSInteger)tableView:(UITableView *)aTableView numberOfRowsInSection:(NSInteger)section 
{
    NSString *match = [monkeyBirthdayIndex objectAtIndex:section]; 

    NSArray *currentMonkey = [barrel filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"SELF.monkeyBirthYear LIKE[cd] %@", match]];
    return [currentMonkey count];

}



-(void)loadView 
{
    [super loadView]; 


    Monkey *monkey1 = [[Monkey alloc] initWithMonkeyName:@"Sam" monkeyBirthYear:@"1964"]; 
    Monkey *monkey2 = [[Monkey alloc] initWithMonkeyName:@"Ham" monkeyBirthYear:@"1964"]; 
    Monkey *monkey3 = [[Monkey alloc] initWithMonkeyName:@"Nim Chimpsky" monkeyBirthYear:@"1965"]; 
    Monkey *monkey4 = [[Monkey alloc] initWithMonkeyName:@"Bubbles" monkeyBirthYear:@"1985"]; 
    Monkey *monkey5 = [[Monkey alloc] initWithMonkeyName:@"George" monkeyBirthYear:@"1980"]; 

    barrel = [NSMutableArray arrayWithObjects:monkey1, monkey2, monkey3, monkey4,monkey5, nil]; 

    monkeyBirthdayIndex = [[NSMutableArray alloc] init]; 

    for (int i=0; i<[barrel count]; i++) {
        //Get the date of each monkeys birthday
        Monkey *m = [barrel objectAtIndex:i]; 

        if (![monkeyBirthdayIndex containsObject:[m monkeyBirthYear]])
        {
            [monkeyBirthdayIndex addObject:[m monkeyBirthYear]];
        }

    }



}

@end

@interface AppDelegate :NSObject <UIApplicationDelegate> 
{
    UIWindow *window; 
}
@end 

@implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 
    ViewController *vc = [[ViewController alloc] init]; 
    UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:vc]; 
    window.rootViewController = nav; 
    [window makeKeyAndVisible]; 
    return YES; 
}




int main(int argc, char *argv[])
{
    @autoreleasepool {
        int returnValue = UIApplicationMain(argc, argv, nil, @"AppDelegate");
        return returnValue; 
    }
}

@end

Answer 1

In tableView:cellForRowAtIndexPath: you return the name of the nth monkey in the barrel:

Monkey *m = [barrel objectAtIndex:[indexPath row]]; 

What you really want is the nth monkey in a subarray filtered out as in tableView: numberOfRowsInSection:.