how to implement date picker on button click in ios?

-(IBAction)datePickerBtnAction:(id)sender
{
    datePicker = [[UIDatePicker alloc]initWithFrame:CGRectMake(0, 0,10, 50)];
    datePicker.datePickerMode = UIDatePickerModeDate;
    datePicker.hidden = NO;
    datePicker.date = [NSDate date];
    [datePicker addTarget:self action:@selector(labelTitle:) forControlEvents:UIControlEventValueChanged];
    [self.view addSubview:datePicker];
    rightBtn = [[UIBarButtonItem alloc]initWithTitle:@"Done" style:UIBarButtonItemStyleDone target:self action:@selector(save:)];
    self.navigationItem.rightBarButtonItem = rightBtn;       
}

-(void)labelTitle:(id)sender
{
    NSDateFormatter *dateFormat = [[NSDateFormatter alloc]init];
    dateFormat.dateStyle = NSDateFormatterMediumStyle;
    [dateFormat setDateFormat:@"MM/dd/yyyy"];
    NSString *str = [NSString stringWithFormat:@"%@",[dateFormat  stringFromDate:datePicker.date]];
    //assign text to label
    label.text=str; 
}

-(void)save:(id)sender
{
    self.navigationItem.rightBarButtonItem = nil;
    [datePicker removeFromSuperview];       
}

Try this:

- (IBAction)date:(id)sender {
    datepicker = [[UIDatePicker alloc] initWithFrame:CGRectMake(0, 250, 325, 300)];
    datepicker.datePickerMode = UIDatePickerModeDate;
    datepicker.hidden = NO;
    datepicker.date = [NSDate date];

    [datepicker addTarget:self
                   action:@selector(labelChange:)
         forControlEvents:UIControlEventValueChanged];
    [self.view addSubview:datepicker]; //this can set value of selected date to your label change according to your condition


       NSDateFormatter *df = [[NSDateFormatter alloc] init];
    [df setDateFormat:@"M-d-yyyy"]; // from here u can change format.. 
    _selectedDate.text = [df stringFromDate:datepicker.date];
}

- (void)labelChange:(id)sender{
    NSDateFormatter *df = [[NSDateFormatter alloc] init];
    [df setDateFormat:@"M-d-yyyy"];
    _selectedDate.text = [NSString stringWithFormat:@"%@",
                          [df stringFromDate:datepicker.date]];
    [datepicker removeFromSuperview];
}