Question

Newbie here,

I have a single component picker set up from a plist, with each item being an array, with multiple strings in each array that the app uses.

Currently the plist structure is like this:

NSDictionary  ->  NSArray  ->  NSString
                     |             |
            Items in Picker     Data for each Item

But now, I want:

NSDictionary  ->  NSDictionary  ->  NSArray  ->  NSString
                      |                |              |
  DIfferent Picker Data Sets      Items in Picker   Data for each Item

So now there would be multiple sets of picker components that I would show using a segmented control etc…

I’m not even sure if this is possible, and I was only hoping it would save me from making many different separate picker controllers.

What has me stumped is just getting everything ingested properly

This is what I have now, it builds successfully but crashes (debug info below):

NSBundle *bundle = [NSBundle mainBundle];

NSString *plistPath = [bundle pathForResource:@"CamerasDatabase" ofType:@"plist"];

NSDictionary *dictionary = [[NSDictionary alloc] initWithContentsOfFile:plistPath];
self.allCameras = dictionary;
[dictionary release];

NSArray *cameraTypes = [self.allCameras allKeys];
self.CamTypes = cameraTypes;

NSArray *items = [self.CamTypes objectAtIndex:0];
self.Cameras = items;

NSString *selectedCamera = [self.Cameras objectAtIndex:0];
NSArray *array = [CamsList objectForKey:selectedCam];
self.cameraData = array;

I’ve tried many different combinations of dictionaries, arrays, and strings so I’m sure the above code is messed up.

It crashes at:

NSString *selectedCamera = [self.Cameras objectAtIndex:0];

with “-[NSCFString objectAtIndex:]: unrecognized selector sent to instance 0x4e127f0”

Answer 1

It is obvious, you are having NSString objects (keys) in self.CamTypes. Not NSArray.

so these lines are invalid

NSArray *items = [self.CamTypes objectAtIndex:0];
self.Cameras = items;

NSString *selectedCamera = [self.Cameras objectAtIndex:0]; //this line is cause of exception.

for fixing this write code some thing like this

NSBundle *bundle = [NSBundle mainBundle];

NSString *plistPath = [bundle pathForResource:@"CamerasDatabase" ofType:@"plist"];

NSDictionary *dictionary = [[NSDictionary alloc] initWithContentsOfFile:plistPath];
self.allCameras = [dictionary valueForKey:@"Key "];//Key for accesing your inner dictionary
[dictionary release];



NSArray *cameraTypes = [self.allCameras allKeys];
self.CamTypes = cameraTypes;


NSArray *items = [self.allCameras valueForKey:[self.CamTypes objectAtIndex:0]];
self.Cameras = items;

NSString *selectedCamera = [self.Cameras objectAtIndex:0];
NSArray *array = [CamsList objectForKey:selectedCam];
self.cameraData = array;

so in above code self.allCameras is the dictionary which having arrays corresponding different key (cameraTypes which are in self.CamTypes).