Question

I’ve added a few components to the NavigationBar in an app I’m creating. The height of the bar changes dynamically, like in Safari for the iPhone, when you click on the URL field. I have all of the interactions and resizings working perfectly, except when I move to another tab and return.

If I start the app, click on second tab the navbar displays correctly.

If I then immediately click on the first tab, and then back to the second tab again, the NavigationBar is clipped.

I’m customizing the navbar in my viewWillAppear method

- (void)viewWillAppear:(BOOL)animated {

    [super viewWillAppear:animated];

    if (navBar == nil) {

        CGFloat width = self.view.frame.size.width;


        navBar = [self.navigationController.navigationBar autorelease];
        navBar.frame = CGRectMake(0,20,width,52);
        //This doesn't appear to have any effect- was set to           
        //UIViewAutoresizingFlexibleWidth and worked but with with the same issue.
        navBar.autoresizingMask = UIViewAutoresizingFlexibleHeight;

        self.navigationItem.title = nil;


        label = [[UILabel alloc] initWithFrame:
             CGRectMake(10,2,width-20,14)];     
        label.autoresizingMask = UIViewAutoresizingFlexibleWidth;
        label.text = @"My Custom NavBar";
        label.backgroundColor = [UIColor clearColor];
        label.font = [UIFont systemFontOfSize:12];
        label.textAlignment = UITextAlignmentCenter;
        [navBar addSubview:label];

        urlTextField = [[UITextField alloc] initWithFrame:
                    CGRectMake(10,19,width-75,26)]; 
        urlTextField.clearButtonMode = UITextFieldViewModeWhileEditing;
        [urlTextField addTarget:(id)self action:@selector(textFieldDidChange:) 
                                        forControlEvents:UIControlEventEditingChanged];


        bookmarkButton = [UIButton buttonWithType:UIButtonTypeCustom];
        bookmarkButton.frame = CGRectMake(0,0,21,21);
        [bookmarkButton setImage:[UIImage imageNamed:@"bookmark.png"] forState:UIControlStateNormal];
        [bookmarkButton addTarget:self action:@selector(bookmarkPressed:) forControlEvents:UIControlEventTouchUpInside];
        urlTextField.leftView = bookmarkButton;
        urlTextField.leftViewMode = UITextFieldViewModeAlways;


        actionButton = [UIButton buttonWithType:UIButtonTypeCustom];
        actionButton.frame = CGRectMake(0,0,21,21);
        [actionButton setImage:[UIImage imageNamed:@"refresh.png"] forState:UIControlStateNormal];
        [actionButton addTarget:self action:@selector(actionPressed:) forControlEvents:UIControlEventTouchUpInside];
        urlTextField.rightView = actionButton;
        urlTextField.rightViewMode = UITextFieldViewModeAlways;


        urlTextField.autoresizingMask = UIViewAutoresizingFlexibleWidth;
        urlTextField.borderStyle = UITextBorderStyleRoundedRect;
        urlTextField.font = [UIFont systemFontOfSize:17];
        urlTextField.delegate = self;
        [navBar addSubview:urlTextField];


    } else {

        //XXX This does make the navBar display correctly
        //but I don't really want the keyboard visible when returning from another tab
        //[urlTextField  becomeFirstResponder];

    }

}

Note the final comment in the code above- If I force the keyboard to display, or if the user clicks in the UITextField, the NavBar is displayed correctly from therein.

I’ve tried a lot of things- checking the frames sizes of the View (View 2 in the images), the NavBar, but with no luck. Does any one have any idea what the problem might be? I’ll be happy to give further detail.

Thanks.

Answer 1

Basically you’re going about this all the wrong way. You should never have to access the frame of the navigation bar (let alone change it) and you should certainly never add subviews to it directly. From the docs:

Unlike other types of views, you do
not add subviews to a navigation bar
directly. Instead, you use a
navigation item (an instance of the
UINavigationItem class) to specify
what buttons or custom views you want
displayed.

So in the -(id)initWithNibName:bundle: method of your view controller you want:

// Setting this will automatically grow the height of the navigation bar
// to the appropriate height
self.navigationItem.prompt = @"My Custom NavBar";

// Construct urlTextField here ...
self.navigationItem.titleView = urlTextField;

// This is the button with the gears icon
UIBarButtomItem *rightButtonItem = [[UIBarButtomItem alloc] initWithCustomView:view];
self.navigationItem.rightBarButtonItem = rightButtomItem;
[rightButtomItem release];