Xcode UIPickerView "NSInvalidArgumentExpression"? - objective-c

Question

I'm trying to implement a UIPickerView in a FlipsideViewController, which is just a settings tab.
Here's the relevant code in the .h file:
#class FlipsideViewController;
#protocol FlipsideViewControllerDelegate<UIPickerViewDataSource, UIPickerViewDelegate>
- (void)flipsideViewControllerDidFinish:(FlipsideViewController *)controller;
#end
#property (strong, nonatomic) IBOutlet UIPickerView *Categories;
#property (strong, nonatomic) NSArray *categoriesData;
#property (strong, nonatomic) NSMutableArray* dataArray;
- (int)numberOfComponentsInPickerView:(UIPickerView *)pickerView;
- (NSInteger)Categories:(UIPickerView *)Categories numberOfRowsInComponent:(NSInteger)component;
- (NSString*)Categories:(UIPickerView *)Categories titleForRow:(NSInteger)row forComponent:(NSInteger)component;
Here's the relevant code in the .m file:
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
_Categories = [[UIPickerView alloc] initWithFrame:CGRectMake((pickerWidth*4/3)/2-pickerWidth/2, 50.0f, pickerWidth, 200.0f)];
_Categories.showsSelectionIndicator = true;
[_Categories selectRow:2 inComponent:0 animated:YES];
[self.view addSubview: _Categories];
_dataArray = [[NSMutableArray alloc] init];
[_dataArray addObject:#"One"];
[_dataArray addObject:#"Two"];
[_dataArray addObject:#"Three"];
[_dataArray addObject:#"Four"];
[_dataArray addObject:#"Five"];
_categoriesData = _dataArray;
_Categories.dataSource = (id)self;
_Categories.delegate = (id)self;
}
- (int)numberOfComponentsInPickerView:(UIPickerView *)Categories
{
return 1;
}
// The number of rows of data
- (NSInteger)Categories:(UIPickerView *)Categories numberOfRowsInComponent:(NSInteger)component
{
return _categoriesData.count;
}
// The data to return for the row and component (column) that's being passed in
- (NSString*)Categories:(UIPickerView *)Categories titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
return [_categoriesData objectAtIndex:row];
}
Sorry if that's a little too much to read. The point is that in the final portion, when - (NSInteger)Categories:(UIPickerView *)Categories numberOfRowsInComponent:(NSInteger)component is run, it returns a "NSInvalidArgumentException". I tried reinitializing the dataArray and categoriesData in each method, to no avail. I'm not sure what I should do... please help. Thanks!
EDIT:
Found the error. It was in the method call... instead of specifying which UIPickerView I was trying to access, I instead should have just put in a generic "UIPickerView". So, it should've looked like this:
- (NSString*)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{}
and not like this:
- (NSString*)pickerView:(UIPickerView *)Categories titleForRow:(NSInteger)row forComponent:(NSInteger)component
- (NSInteger)pickerView:(UIPickerView *)Categories numberOfRowsInComponent:(NSInteger)component{}
Hope this helps anyone finding a similar problem.

Answer 1

It looks like categoriesData is not assigning the value properly. Try to change this line below and check:-
self.categoriesData = _dataArray;