[__NSArrayI pickerView:numberOfRowsInComponent:]: unrecognized selector sent to instance - ios

Question

the basic premise of this code is that it has two fields, a textfield that stores the height of the person in feet, and one that stores the height in inches. Thus, when someone clicks the feet textfield or the inches text field, a pickerview pops up that allows the user to pick the height. However, I'm getting the following error:
[__NSArrayI pickerView:numberOfRowsInComponent:]: unrecognized selector sent to instance
When I run the following code:
#import "GetUserStatistics.h"
#interface GetUserStatistics ()
#end
#implementation GetUserStatistics
#synthesize feetField, inchesField, pickerViewFeet, pickerViewInches, ftPicker, inPicker;
- (void)viewDidLoad {
[super viewDidLoad];
pickerViewFeet = [self createNumberPickerViewWithStartingValue:1 endingValue:8 defaultValue:5];
NSLog(#"%f", pickerViewFeet.frame.size.height);
feetField.inputView = pickerViewFeet;
NSLog(#"%f", feetField.inputView.frame.size.height);
//feetField.inputAccessoryView = [self createToolbar];
pickerViewInches = [self createNumberPickerViewWithStartingValue:0 endingValue:11 defaultValue:8];
NSLog(#"%f",pickerViewInches.frame.size.height);
inchesField.inputView = pickerViewInches;
NSLog(#"%f", inchesField.inputView.frame.size.height);
//NSLog(#"%#", pickerViewFeet.delegate);
//inchesField.inputAccessoryView = [self createToolbar];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (BOOL)disablesAutomaticKeyboardDismissal
{
return NO;
}
-(void) inputAccessoryViewDidFinish{
feetField.text = [[NSString alloc]initWithFormat:#"%i", [(UIPickerView *)feetField.inputView selectedRowInComponent:0]];
inchesField.text = [[NSString alloc]initWithFormat:#"%i", [(UIPickerView *)inchesField.inputView selectedRowInComponent:0]];
actualHeight = ([feetField.text intValue])*12 + [inchesField.text intValue];
NSLog(#"actual height:%i", actualHeight);
[feetField endEditing:YES];
[inchesField endEditing:YES];
}
-(UIPickerView *) createNumberPickerViewWithStartingValue: (int) startVal endingValue: (int) endingVal defaultValue: (int) defaultValue{
UIPickerView * tempPicker = [[UIPickerView alloc]initWithFrame:CGRectMake(0, 50, 100, 150)];
ftPicker = [[NumberPickerView alloc]initWithStartingValue:startVal endingVal:endingVal];
tempPicker.delegate = ftPicker;
[tempPicker selectRow:defaultValue inComponent:0 animated:NO];
return tempPicker;
}
-(UIToolbar * ) createToolbar{
UIToolbar *myToolbar = [[UIToolbar alloc] initWithFrame:
CGRectMake(0,0, 320, 44)]; //should code with variables to support view resizing
UIBarButtonItem *doneButton =
[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone
target:self action:#selector(inputAccessoryViewDidFinish)];
//using default text field delegate method here, here you could call
//myTextField.resignFirstResponder to dismiss the views
[myToolbar setItems:[NSArray arrayWithObject: doneButton] animated:NO];
return myToolbar;
}
-(void) addPickerViewToTextField: (UITextField **) textField pickerViewToAdd : (UIPickerView **) pickerView{
NSLog(#"dading view");
*pickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 50, 100, 150)];
}
#end
NumberPickerView code (implements the UIPickerViewDelegate protocol):
-(NumberPickerView *) initWithStartingValue: (int) startingVal endingVal: (int) endingVal
{
startingValue = startingVal;
endingValue = endingVal;
return self;
}
// returns the number of 'columns' to display.
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
return 1;
}
// returns the # of rows in each component..
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
NSLog(#"calling this function");
return endingValue - startingValue + 1;
}
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
return [[NSString alloc]initWithFormat:#"%i", (int)(row) + startingValue];
}
I suspect the issue is with the returning of the UIPickerView, specifically that the NumberPickerView is being destroyed after the function returns the view and so the pickerViewFeet no longer has a delegate. I'm not sure if this is the problem, and if it is how to fix this, can anyone help?
Thanks!

Answer 1

You call createNumberPickerViewWithStartingValue twice. The 2nd call results in ftPicker being reset to a new instance of NumberPickerView. This means the first instance assigned to the first picker view gets deallocated. And this results in the crash.
You need to reorganize your code so the same instance variable isn't being used to hold the two NumberPickerView instances.
You also need a newer tutorial. You shouldn't be calling #synthesize in most cases. And all of your references to the property instance variables should be changed to references to the actual property instead.

Answer 2

first use self.ftPicker instead of ftpicker and:
-(NumberPickerView *) initWithStartingValue: (int) startingVal endingVal:(int) endingVal {
self = [super init];
startingValue = startingVal;
endingValue = endingVal;
return self;
}