UIPickerView shows up but does not load data - ios

Question

I am pretty new to objective c. I have looked through a ton of questions on stack overflow to try to find an answer but nothing has helped, so I appreciate any help anyone can offer.
I am trying to make an app that will have the picker view load from my array of 51 numbers. a random object will be generated from the array and if the user selects that object from the picker, an alert will show. I'm going to make a simple little guessing game, but for now I just have the picker that loads but is blank with no text. The alerts do work tho.
I have already assigned datasource and delegate to picker view on the view controller.
I need help figuring out why my picker view is not loading my array and what I can do to fix it. Thank you
here is my h file:
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController <UIPickerViewDataSource, UIPickerViewDelegate>
#property (strong, nonatomic) IBOutlet UIPickerView *picker;
#end
here is m file:
#import "ViewController.h"
#interface ViewController ()
#property NSArray *numbers;
#property NSString * selection;
#property NSString *randomObject;
#property NSInteger rnd;
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor darkGrayColor];
[_numbers arrayByAddingObjectsFromArray:_numbers];
}
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
return 1;
}
-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent: (NSInteger)component{
return _numbers.count;
}
-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
_numbers = #[#0,#1,#2,#3,#4,#5,#6,#7,#8,#9,#10,#11,#12,#13,#14,#15,#16,#17,#18,#19,#20,#21,#22,#23,#24,#25,#26,#27,#28,#29,#30,#31,#32,#33,#34,#35,#36,#37,#38,#39,#40,#41,#42,#43,#44,#45,#46,#47,#48,#49,#50];
//create random object from array
_rnd = arc4random() % ([_numbers count]);
_selection = [NSString stringWithFormat:#"%ld",(long)row];
_randomObject = [_numbers objectAtIndex:self.rnd];
NSLog(#"%#",self.randomObject);
//strings for alerts
NSString *right = [[NSString alloc]initWithFormat:#"You Guessed Right! Congratulations you've earned 3 points!"];
NSString *oneOff = [[NSString alloc]initWithFormat:#"You were so close! Only 1 off! The number was %lu. Congratulations you've earned 2 points!",(unsigned long)self.rnd];
NSString *twoOff = [[NSString alloc]initWithFormat:#"You were so close! Only 2 off! The number was %lu. Congratulations you've earned 1 point!",(unsigned long)self.rnd];
NSString *threeOff = [[NSString alloc]initWithFormat:#"Nice try! You were 3 off. The number was %lu. You earned -1 point.",(unsigned long)self.rnd];
NSString *fourOff = [[NSString alloc]initWithFormat:#"Good try! You were 2 off. The number was %lu. You earned -2 points.",(unsigned long)self.rnd];
NSString *fiveOff = [[NSString alloc]initWithFormat:#"You were no where close! The number was %lu. You earned -3 points!",(unsigned long)self.rnd];
//alerts for guesses
UIAlertView *rightAlert = [[UIAlertView alloc]initWithTitle:#"Spot On!" message:right delegate:nil cancelButtonTitle:#"Sweet!" otherButtonTitles:nil, nil];
UIAlertView *oneOffAlert = [[UIAlertView alloc]initWithTitle:#"Only one off!" message:oneOff delegate:nil cancelButtonTitle:#"Ok!" otherButtonTitles:nil, nil];
UIAlertView *twoOffAlert = [[UIAlertView alloc]initWithTitle:#"Only Two Off!" message:twoOff delegate:nil cancelButtonTitle:#"Ok!" otherButtonTitles:nil, nil];
UIAlertView *threeOffAlert = [[UIAlertView alloc]initWithTitle:#"Three Off" message:threeOff delegate:nil cancelButtonTitle:#"Ok" otherButtonTitles:nil, nil];
UIAlertView *fourOffAlert = [[UIAlertView alloc]initWithTitle:#"Four Off" message:fourOff delegate:nil cancelButtonTitle:#"Ok" otherButtonTitles:nil, nil];
UIAlertView *fiveOffAlert = [[UIAlertView alloc]initWithTitle:#"No Where Close!" message:fiveOff delegate:nil cancelButtonTitle:#"Ok!" otherButtonTitles:nil, nil];
NSInteger a = [_selection integerValue];
//guessed right
if (_selection == _randomObject)
{
[rightAlert show];
}
//one off
if (a == (_rnd + 1) || (a == (_rnd - 1)))
{
[oneOffAlert show];
}
//two off
if (a == (_rnd + 2) || (a == (_rnd - 2)))
{
[twoOffAlert show];
}
//three off
if (a == (_rnd + 3) || (a == (_rnd - 3)))
{
[threeOffAlert show];
}
//four off
if (a == (_rnd + 4) || (a == (_rnd - 4)))
{
[fourOffAlert show];
}
//five or more off
if ((_rnd + 5) >= a || (_rnd - 5) <= a ||(_rnd - 5) >= a || (_rnd + 5) <= a)
{
[fiveOffAlert show];
}
}
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
return _numbers[row];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end

Answer 1

The problem is that this line
_numbers = #[#0,#1,#2,#3,#4,#5,#6,#7,#8,#9,#10,#11,#12,#13,#14,#15,#16,#17,#18,#19,#20,#21,#22,#23,#24,#25,#26,#27,#28,#29,#30,#31,#32,#33,#34,#35,#36,#37,#38,#39,#40,#41,#42,#43,#44,#45,#46,#47,#48,#49,#50];
appears in the wrong place. It is in the pickerView:didSelectRow:inComponent: method which is only called after the user has made a selection. Therefore, your _numbers array will always be empty.
Move it to the viewDidLoad method, replacing the following statement which currently hasn't any effect at all:
[_numbers arrayByAddingObjectsFromArray:_numbers];
Also, you need to change this method:
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
return [_numbers[row] stringValue];
}
because _numbers[row] is an NSNumber, not an NSString.