Ios – presentViewController and displaying navigation bar

iosiphonemodalviewcontrollerpresentmodalviewcontrolleruiviewcontroller

I have a view controller hierarchy and the top-most controller is displayed as a modal and would like to know how to display the navigation bar when using

'UIViewController:presentViewController:viewControllerToPresent:animated:completion'

The docs for 'presentViewController:animated:completion:' note:

'On iPhone and iPod touch, the presented view is always full screen.
On iPad, the presentation depends on the value in the
modalPresentationStyle property.'

For 'modalPresentationStyle', the docs say:

The presentation style determines how a modally presented view controller is displayed onscreen. On iPhone and iPod touch, modal view controllers are always presented full-screen, but on iPad there are several different presentation options.

Is there way to ensure that the navigation bar is visible below the status bar once the view control displays itself? Should I interpret the doc as, you don't get any options of iPhone/iPod and only on iPad?

Previously, I was using 'UIViewController:presentModalViewController:animated' which worked fine, but since iOS 5.0, the API has been deprecated so I'm switching over to the new one.

Visually, what I'm looking to do is have the new controller slide in from the bottom of the screen, just like the old API used to do.

[updating with code]:

// My root level view:
UIViewController *vc = [[RootViewController alloc] 
                            initWithNibName:nil 
                            bundle:[NSBundle mainBundle]];
navController = [[UINavigationController alloc] initWithRootViewController:vc];        
....

// Within the RootViewController, Second view controller is created and added 
// to the hierarchy. It is this view controller that is responsible for 
// displaying the DetailView:
SecondTierViewController *t2controller = [[SecondTierViewController alloc] 
                                           initWithNibName:nil
                                           bundle:[NSBundle mainBundle]];

[self.navigationController pushViewController:t2controller animated:YES];

// Created by SecondTierViewController 
DetailViewController *controller = [[DetailViewController alloc] initWithNibName:nil                                                                                 
                                        bundle:[NSBundle mainBundle]];  

controller.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
controller.modalPresentationStyle = UIModalPresentationCurrentContext;

[self.navigationController presentViewController:controller 
                                        animated:YES 
                                        completion:nil];

Best Answer

It is true that if you present a view controller modally on the iPhone, it will always be presented full screen no matter how you present it on the top view controller of a navigation controller or any other way around. But you can always show the navigation bar with the following workaround way:

Rather than presenting that view controller modally present a navigation controller modally with its root view controller set as the view controller you want:

MyViewController *myViewController = [[MyViewController alloc] initWithNibName:nil bundle:nil];
UINavigationController *navigationController = 
    [[UINavigationController alloc] initWithRootViewController:myViewController];

//now present this navigation controller modally 
[self presentViewController:navigationController
                   animated:YES
                   completion:^{

                        }];

You should see a navigation bar when your view is presented modally.

Related Solutions

Ios – What’s the difference between the atomic and nonatomic attributes

The last two are identical; "atomic" is the default behavior (~~note that it is not actually a keyword; it is specified only by the absence of nonatomic~~ -- atomic was added as a keyword in recent versions of llvm/clang).

Assuming that you are @synthesizing the method implementations, atomic vs. non-atomic changes the generated code. If you are writing your own setter/getters, atomic/nonatomic/retain/assign/copy are merely advisory. (Note: @synthesize is now the default behavior in recent versions of LLVM. There is also no need to declare instance variables; they will be synthesized automatically, too, and will have an _ prepended to their name to prevent accidental direct access).

With "atomic", the synthesized setter/getter will ensure that a whole value is always returned from the getter or set by the setter, regardless of setter activity on any other thread. That is, if thread A is in the middle of the getter while thread B calls the setter, an actual viable value -- an autoreleased object, most likely -- will be returned to the caller in A.

In nonatomic, no such guarantees are made. Thus, nonatomic is considerably faster than "atomic".

What "atomic" does not do is make any guarantees about thread safety. If thread A is calling the getter simultaneously with thread B and C calling the setter with different values, thread A may get any one of the three values returned -- the one prior to any setters being called or either of the values passed into the setters in B and C. Likewise, the object may end up with the value from B or C, no way to tell.

Ensuring data integrity -- one of the primary challenges of multi-threaded programming -- is achieved by other means.

Adding to this:

atomicity of a single property also cannot guarantee thread safety when multiple dependent properties are in play.

Consider:

 @property(atomic, copy) NSString *firstName;
 @property(atomic, copy) NSString *lastName;
 @property(readonly, atomic, copy) NSString *fullName;

In this case, thread A could be renaming the object by calling setFirstName: and then calling setLastName:. In the meantime, thread B may call fullName in between thread A's two calls and will receive the new first name coupled with the old last name.

To address this, you need a transactional model. I.e. some other kind of synchronization and/or exclusion that allows one to exclude access to fullName while the dependent properties are being updated.

Html – Trouble loading html file from plist to webView on iPhone

You can try it this way:

NSString *bundle = [[NSBundle mainBundle] bundlePath];
NSString *webPath = [bundle stringByAppendingPathComponent:{htmlFilename}]
UIWebView* browser = [[UIWebView alloc] initWithFrame:
                              CGRectMake(0, 0, 200, 300)];
[browser loadRequest:[NSURLRequest requestWithURL:
                              [NSURL fileURLWithPath:webPath]]];
[self addSubview:browser];

You'll also want to set delegates on the browser so you get informed when the contents have finished loading.

Best Answer

Related Solutions

Ios – What’s the difference between the atomic and nonatomic attributes

Html – Trouble loading html file from plist to webView on iPhone

Related Topic