UIDatePicker doesn't change value - ios

Question

I have UIViewController with UIDatePicker inside. I connect UIDatePicker with IBOutlet property in header class, because I'm using storyboards in my app:
#import <UIKit/UIKit.h>
#protocol CreationDateDelegate <NSObject>
#optional
-(void)selectedDateIs:(NSString*)dateValue;
#end
#interface SelectCreationDateViewController : UIViewController
{
IBOutlet UIDatePicker *datePicker;
}
#property (nonatomic,assign)id<CreationDateDelegate>creationDateDelegate;
#property (nonatomic,retain) IBOutlet UIDatePicker *datePicker;
#end
--- .m -----
#import "SelectCreationDateViewController.h"
#interface SelectCreationDateViewController ()
{
NSString *dateFromString;
}
#end
#implementation SelectCreationDateViewController
#synthesize creationDateDelegate,datePicker;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self)
{
}
return self;
}
- (void)viewDidLoad
{
self.title = #"Select creation date";
[super viewDidLoad];
[datePicker setHidden:NO];
datePicker.timeZone = [NSTimeZone localTimeZone];
[datePicker setDatePickerMode:UIDatePickerModeDate];
[datePicker addTarget:self action:#selector(changeValueOfDatePicker:) forControlEvents:UIControlEventValueChanged];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(void)viewWillDisappear:(BOOL)animated{
NSDateFormatter *formatter = [[NSDateFormatter alloc]init];
NSString *dateFromString = [formatter stringFromDate:datePicker.date];
[self.creationDateDelegate selectedDateIs:dateFromString];
}
-(void)changeValueOfDatePicker:(id)sender{
NSDateFormatter *formatter = [[NSDateFormatter alloc]init];
dateFromString = [formatter stringFromDate:datePicker.date];
[self.creationDateDelegate selectedDateIs:dateFromString];
NSLog(#"Date from string value equal %#",dateFromString);
}
#end
Why every time when I change the value of the DatePicker returned value does not change? Any ideas? Also, let me know if I am making any mistake in the code.

Answer 1

Set some dateformate also
-(void)changeValueOfDatePicker:(id)sender{
NSDateFormatter *formatter = [[NSDateFormatter alloc]init];
[formatter setDateFormat:#"yyyy-MM-dd HH:mm"];
dateFromString = [formatter stringFromDate:datePicker.date];
[self.creationDateDelegate selectedDateIs:dateFromString];
NSLog(#"Date from string value equal %#",dateFromString);
}

Answer 2

Fix it by adding this line of code,
only if you are using iOS7
- in method (void)viewDidLoad method
[self.datePicker setDate:[NSDate date] animated:YES];