Trying to add UINavigation Bar programmatically but it is not showing up

- (UINavigationBar *) navBar {
    if (_navBar) {
        _navBar = [[UINavigationBar alloc] init];
        [_navBar setBackgroundColor:[UIColor blueColor]];
        _navBar.frame = CGRectMake(0, 0, self.view.bounds.size.width, 44);
    }
    return _navBar;
}

//
//  MySecondViewController.m
//  Example2

#import "MySecondViewController.h"

@interface MySecondViewController ()
@property (nonatomic) UIButton *stocksButton;
@property (nonatomic) UIButton *weatherButton;
@property (nonatomic) UINavigationBar *navBar;

@end

@implementation MySecondViewController

- (id) init {

    if (self = [super init]) {

    }
    return self;
}

- (void)viewDidLoad {
    [super viewDidLoad];

    // Do any additional setup after loading the view.
    UIColor *tealColor = [UIColor colorWithRed:200.0/255.0 green:191.0/255.0 blue:231.0/255.0 alpha:1.0];
    self.view.backgroundColor = tealColor;




    [self.view addSubview:self.stocksButton];
    [self.view addSubview:self.weatherButton];
    [self.view addSubview:self.navBar];

    NSDictionary *elementsDict = NSDictionaryOfVariableBindings(_stocksButton, _weatherButton);



    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-(>=150)-[_stocksButton]-(<=20)-[_weatherButton(==_stocksButton)]-(>=150)-|"
                                                                     options:NSLayoutFormatDirectionLeadingToTrailing
                                                                     metrics:nil
                                                                       views:elementsDict]];

    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-(<=50)-[_stocksButton]-(<=50)-|"
                                                                      options:NSLayoutFormatDirectionLeadingToTrailing
                                                                      metrics:nil
                                                                        views:elementsDict]];


    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-(<=50)-[_weatherButton]-(<=50)-|"
                                                                      options:NSLayoutFormatDirectionLeadingToTrailing
                                                                      metrics:nil
                                                                        views:elementsDict]];



}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - UI elements

- (UIButton *) stocksButton {
    if (!_stocksButton) {
        _stocksButton = [[UIButton alloc] init];
        [_stocksButton setTranslatesAutoresizingMaskIntoConstraints:NO];
        UIColor *goldenrodColor = [UIColor colorWithRed:218.0/255.0 green:165.0/255.0 blue:32.0/255.0 alpha:1.0];
        [_stocksButton setBackgroundColor:goldenrodColor];
        [_stocksButton setTitle:@"Stocks" forState:UIControlStateNormal];
    }
    return _stocksButton;
}

- (UIButton *) weatherButton {
    if (!_weatherButton) {
        _weatherButton = [[UIButton alloc] init];
        [_weatherButton setTranslatesAutoresizingMaskIntoConstraints:NO];
        UIColor *rawsiennaColor = [UIColor colorWithRed:199.0/255.0 green:97.0/255.0 blue:20.0/255.0 alpha:1.0];
        [_weatherButton setBackgroundColor:rawsiennaColor];
        [_weatherButton setTitle:@"Weather" forState:UIControlStateNormal];
        CGRect frame = _weatherButton.frame;
        frame.size = _weatherButton.intrinsicContentSize;

    }
    return _weatherButton;
}

- (UINavigationBar *) navBar {
    if (_navBar) {
        _navBar = [[UINavigationBar alloc] init];
        [_navBar setBackgroundColor:[UIColor blueColor]];
        _navBar.frame = CGRectMake(0, 44, self.view.bounds.size.width, self.view.bounds.size.height);
    }
    return _navBar;
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

@end