I'm slowly picking up Objective-C and the iPhoneSDK but I'm having some problems getting my head around the MVC pattern.
I'm fleshing out a game which I hope will have screens like a splash screen, title, help etc. What I'm currently doing is creating a new UIViewController and a new nib for each of these screens, is this the right practice? In the main AppDelegate I've created methods that show the views and add them with [window addSubView:controller.view]. What I'm finding is that with the show/hide code sat in the AppDelegate, I have to create a reference of the AppDelegate in the loaded controller in order to target the hide code.
This seems a bit awkward but I expect I'm probably approaching this wrong, how do you guys usually do this sort of thing?
// example from AppDelegate
-(IBAction)showHelp:(id)sender
{
helpScreen = [[helpController alloc] initWithNibName:#"helpView" bundle:nil];
// send copy of self in order to target closeHelp method from InterfaceBuilder
helpScreen.appDel = self;
helpScreen.view.alpha = 0;
[window addSubview:helpScreen.view];
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:1.0];
helpScreen.view.alpha = 1.0;
[UIView commitAnimations];
}
Many Thanks,
UIViewController and a new nib for each of these screens, is this the right practice
Yeap!
[window addSubView:controller.view]
Are you also removing the old views at the end of the animation? You should be, otherwise you would have multiple view controllers running at once, something that you really don't want.
What I'm finding is that with the
show/hide code sat in the AppDelegate,
I have to create a reference of the
AppDelegate in the loaded controller
in order to target the hide code
Well somewhere you need the code that's responsible for switching views, and if the views can control this switching then they do need a way to trigger that. Rather than app delegate I usually have a RootViewController that performs these changes.
I tend to derive each of these views from a base class that has a delegate property for performing these changes. When the views need to change they call functions in the delegate. These are usually;
pushView - temporarily pushes the view as active, current view is removed from the view hierarchy but not destroyed. This would be used for something like a help screen.
popView - current view is destroyed and the previous view is reinstated. This is how the help screen would remove itself.
changeView - current view is destroyed and replaced with the specified view. This might be how you change from page1 to page2 of the help.
E.g.
// your root controller
-(void) changeView:(UIViewController) newController
{
newController = blah blah;
newController.delegate = self;
// add newController view, remove old one etc
}
// new controller
-(void) userPressedHelp
{
UIViewController* help = blah blah;
[self.delegate pushView: newController];
}
// help controller
-(void) userPressedOk
{
[self.delegate popView];
}
That seems reasonable to me. I'm pretty new to Obj-C but that's how I've done an application.
As long as the ViewControllers don't have knowledge of each other, I think you are doing just fine.
Related
This question has been asked a lot e.g. here but as far as I can see is yet to be answered in full.
I have a UITabBarController with a UINavigationController as the root vc for one of the tabs, which itself has a MKMapView as its root vc. The behaviour I want is for the map to partially curl upwards, while leaving the tab bar in place (similar to the Maps app).
So far all I have managed to get working is for the whole view to curl, which isn't as nice.
Solutions I have seen are to set the hidesBottomBarWhenPushed property to NO, which would make sense however this doesn't seem to work, (unless I am doing something wrong).
For clarity, my code is as follows:
MyVC *aView = [MyVC init];
aView.modalTransitionStyle = UIModalTransitionStylePartialCurl;
aView.hidesBottomBarWhenPushed = NO;
For the presenting part, I have tried the two alternatives below, neither of which seem to work:
[self presentModalViewController:updateStatus animated:YES];
[[self navigationController] presentModalViewController:updateStatus animated:YES];
Any help much appreciated.
I've scoured StackOverflow (and the Internet) for a solution to this problem. The question has been asked many times, but as you note, never sufficiently answered. Many solutions give an acceptable solution if it is unimportant whether, e.g., a lower toolbar curls up as well.
Others have provided a solution using UIView animations / CoreAnimation rather than UIModalTransitionStylePartialCurl as a modal transition style; this is at worst a solution not allowed in the App Store, and at best is not quite the same effect as one gets from UIModalTransitionStylePartialCurl (e.g. the shape of the curl is different).
None of these solutions have provided an answer that mimics Apple's solution in the Maps app (i.e., using UIModalTransitionStylePartialCurl but leaving an un-curled UIToolbar at the bottom of the screen).
I will continue in this tradition of incomplete answers, since you ask about a UITabBarController and my solution doesn't specifically address that case. It does, however, solve the problem I had, which was to get a half page curl with an un-curled toolbar at the bottom.
There must be a more elegant way to do this, but this is how I managed.
The rootViewController of my AppDelegate is a subclass of UIViewController, which I'll call TAContainerViewController. TAContainerViewController manages a) the actual contents of the screen (the "stuff to be curled"), TAContentViewController, and b) the contents "behind" the TAContentViewController (e.g. settings), which I'll call TAUnderCurlViewController.
My instance of TAContainerViewController had properties for a TAContentViewController and a TAUnderCurlViewController. The UIView that was my content was a subview of TAContentViewController's view property; likewise what the user sees under the curl is the view property of the TAUnderCurlViewController.
In the init method of TAContainerViewController I make sure to do the following:
_underCurlVC.modalTransitionStyle = UIModalTransitionStylePartialCurl;
And to curl the contents to reveal under the page, I set up an action that calls this code:
[self.contentVC presentModalViewController:self.underCurlVC animated:YES];`
where self is the TAContainerViewController, contentVC is an instance of TAContentViewController, and underCurlVC is an instance of TAUnderCurlViewController.
To dismiss the view, simply [self.contentVC dismissModalViewControllerAnimated:YES];.
Some strangeness seems to occur with the frame of contentVC when the modal view is dismissed, so I manually reset the frame when the modal view is dismissed.
I've posted a sample project with more details on Github. Hopefully someone can take this and turn it into a slightly more elegant solution, or expand it to work with a UINavigationController or UITabBarController. I think the trick is to pull the View Controllers out of the well-defined relationships in the Cocoa subclasses, so maybe subclassing those specialty View Controllers would do it.
Tim Arnold's response worked great for me, thanks!
One trap to watch out for: your modal page-curl transition will take over the whole screen if your content view controller is added as a child of the container view controller. You could just not add it as a child, but then none of the view lifecycle methods will get called on your content controller (e.g. viewDidLoad, viewWillAppear), which could be a problem.
Fortunately, there is a way around this. In your container controller:
Add your content controller as a child in viewDidLoad
Remove it as a child in viewDidAppear
Re-add it as a child in viewWillDisappear.
That way, your content controller gets its lifecycle methods called, while still being able to do a modal page-curl transition without taking up the whole screen.
Here is the entire code of a bare-bones solution:
#interface XXContainerController : UIViewController
#property (strong, nonatomic) UIViewController *contentController;
#property (nonatomic) BOOL curled;
#end
#implementation XXContainerController
#synthesize contentController = _contentController;
#synthesize curled = _curled;
- (void)viewDidLoad
{
[super viewDidLoad];
self.contentController = [self.storyboard
instantiateViewControllerWithIdentifier:#"SomeControllerInStoryboard"];
// Add content controller as child view controller.
// This way, it will receive all the view lifecycle events
[self addChildViewController:self.contentController];
self.contentController.view.frame = self.view.bounds;
[self.view addSubview:self.contentController.view];
[self.contentController didMoveToParentViewController:self];
}
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
// Remove the content controller as child view controller.
// This way, the modal page curl transition will
// not take over the whole screen.
// NOTE: need to wait until content controller has appeared
// (which will happen later).
// Achieve this by running the code at the end of the animation loop
[UIView animateWithDuration:0 animations:nil completion:^(BOOL finished) {
[self.contentController removeFromParentViewController];
}];
}
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
// Add the content controller as child view controller again
// so it receives the view lifecycle events
[self addChildViewController:self.contentController];
}
- (void)setCurled:(BOOL)curled
{
if (curled == _curled) return;
_curled = curled;
// Curl up the content view and show underneath controller's view
if (curled) {
// Note you can specify any modal transition in storyboard
// E.g. page curl, flip horizontal
[self.contentController
performSegueWithIdentifier:#"SomeModalSegueDefinedInStoryboard"
sender:self];
// Uncurl and show the content controller's view again
} else {
[self.contentController dismissModalViewControllerAnimated:YES];
// Have to do this, otherwise the content controller's view
// gets messed up for some reason
self.contentController.view.frame = self.view.bounds;
}
}
#end
Basically i have a WebView on SecondViewController and I wish for the WebView to be visible on every view like a tab bar and fully controllable on each view.
Please note the WebView will be on a webpage with a online slideshow so I cannot simply reload on each view
Also in the SecondViewController I have
- (void)webViewDidFinishLoad:(UIWebView *)YouTubePlayer {
I would suggest adding the webView on you window after the you add the tabbarcontroller.view just like:
[window addSubview:tabbarController.view];
[window addSubview:webview];
[window makeKeyAndVisible];
and initially make don't make it visible. You should handle all the webview related methods in the app delegate. Now whenever you don't need it you can hide it by calling the methods your wrote in app delegate from your view controllers.
Hope this helps.
I'd just set up a singleton UIWebView and add it to each view-controller-view when that view controller is about to become visible. Here's one way to do it:
//.h
#interface SharedWebView : UIWebView
{
}
+ (SharedWebView*) shared;
#end
//.m
SharedWebView* g_sharedWebView;
#implementation SharedWebView
+ (SharedWebView*) shared
{
if ( g_sharedWebView == nil )
{
g_sharedWebView = [[SharedWebView alloc] init];
// ... any other intialization you want to do
}
return g_sharedWebView;
}
#end
// in your view controller(s)
#property (readonly) UIWebView* webView
- (UIWebView*) webView
{
return [SharedWebView shared];
}
- (void) viewWillAppear: (BOOL) animated
{
[super viewWillAppear: animated];
[self.view addSubview: self.webView ];
self.webView.frame = CGRectMake(10, 10, 300, 300);
// want to re-set the delegate?
// self.webView.delegate = self;
}
The simplest approach is to just make all of your view controllers aware of this extra view (make the view available through a singleton PinnedViewController or whatever). During each view controller's -viewWillAppear, just do this:
[self addSubview:[[PinnedViewController sharedController] view]];
This will move the view to whoever is currently active (making a view your subview automatically removes you from your old hierarchy).
If that is cumbersome or otherwise unworkable, there are two other options. First, you can subclass UITabViewController (I assume that's what you're using here from your question), and inject your extra view (resizing the content view to make room). This is undocumented and unsupported, so take heed. But it's not incredibly difficult if you don't do too many other fancy tricks.
The other tricky solution is to create a second UIWindow that you float over the main UIWindow (or resize the main UIWindow to make room for it). This is only semi-documented and is also not really supported. But this approach can work if you're trying to put the extra view below the tabbar for instance.
But if your system is simple enough, I recommend just letting your view controllers all manage the pinned view manually. You'll save a lot of code spelunking that way, and you won't have to rely on any undocumented internal view hierarchies.
Sounds like you try to put views on top of this view but not modal. There was this blog entry I once saw that described how you would do something like this. I think it should apply also for your case: semi-modal-transparent-dialogs-on-the-iphone
In iOS UIViewControllers are expected to manage an entire "screen" worth of content so it's not normal to try to share a single view across many view controllers. Trying to have UIViewControllers whose views only manage part of their window is problematic and will result in unexpected behavior as UIKit will not send messages like -viewWillAppear to all view controllers with visible views. Instead you would normally create a single UIViewController whose view includes that web view and whatever other views compose your tab like interface.
Alternately you could have a hierarchy of many view controllers and add a single web view as a subview of all of them. You would then pull your web view delegate behavior out into some non-UIViewController controller class to manage the behavior of the web view.
You can have all your views take up a portion of the screen and have your UIWebView take up the rest. The logic for switching between the other views should remain the same.
For example, in your viewDidLoad method for your UIViewControllers, you could have something like:
self.view.frame = CGRectMake(0, 100, 320, 380);
And in your (say) AppDelegate, you would have your normal call to show the main UIViewController (in your case, it sounds like a UITabBarController?) and also have a call to add the UIWebView. Say, something like:
myWebView.view.frame = CGRectMake(0, 0, 320, 100);
The view controllers and UIWebView would be independent of each other.
You see this pattern, I believe, with apps that have iAds. I've done something just like this with one of my free apps.
Hope this helps!
I got the same effect by simply adding it to the navigationController itself(if you don't have one then just add it).
works great for me in one of my apps.
Could you not use two webviews on your application and simply change the uppermost webview with your more dynamic content?
Im new to iPhone development and I have really taken this to me. I love it, but there is one thing thats naggin' me. How do I keep switching view? I know how to come from first view that is given to me when I create a new project, to a view that I make, but how do I get passed this two windows? How do I get from to views that I created?
I have this app which have a main window with a NavigationController whih is feed with a UITableViewController. This is my main menu. I have a in the upper right corner, a "+"-button which gives me a new view, but how do I get a new view from here? How do I push a new view when the user pick something to add?
Hope someone understand my question. A link to some documentation would be fine. I have looked everywhere.
You can do this many diffrent way, you can do what the Sebastian said, you can also have a common RootViewController that manages your other view controllers view. This is what I like to do, I actually define a protocol on the RootViewController something like ToggleView:UIViewController newController UIViewController:oldController. I make any UIViewController that i want to be able to switch from that view to another implement this protocol. This makes since because generally when you click on a button, you know what View you want to go to next. So when a user clicks the button, in the UIViewController that owns the button i create the new ViewController whose view i want pushed into the screen, this is nice because it also allows me to set up data in the view controller and not have to delegate it to some other object or use a singleton to get the data in the new view, then i call my toggleView methods and the root view controller does the switching. I find this works pretty well and theres berely any code involved. I dont always u se this though, if I know a new view will always come out of another particular view, (for example a home page where one views events and creation of those events), in this case I will loosly couple the view controllers by using protocols.
For that particular situation, people usually use the presentModalViewController:animated: method of UIViewController. UINavigationController is a subclass of UIViewController, so your code would look something like this:
UIViewController *addingViewController = [[UIViewController alloc] initWithNibName:#"AddingView" bundle:nil];
[[self navigationController] presentModalViewController:addingViewController animated:YES];
[addingViewController release];
Here is the rootviewcontrollerdelegate definition
#protocol RootViewControllerViewDelegate
-(void)toggleView:(UIViewController )newController viewController:(UIViewController)oldController;
#end
a possible implementation to toggleView
-(void)toggleView:(UIViewController *)newController viewController:(UIViewController*)oldController {
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:1];
[UIView setAnimationTransition:([oldController.view superview] ? UIViewAnimationTransitionFlipFromLeft : UIViewAnimationTransitionFlipFromLeft) forView:self.view cache:YES];
[newController viewWillAppear:YES];
[oldController viewWillDisappear:YES];
[oldController.view removeFromSuperview];
[self.view addSubview:newController.view];
[oldController viewDidDisappear:YES];
[newController viewDidAppear:YES];
[UIView commitAnimations];
[oldController release];
}
This will swipe the view controllers by flipping the view
Obviously you must make a new RootViewController somewhere and start with a view there, (could be the app delegate)
Now if you want a ViewController to be able to use the RootViewController it must conform to the protocol, you declare it in that classes interface like so
#interface MyViewController : UIViewController <RootViewControllerDelegate> {
id delegate;
}#property(assign) id <RootViewControllerViewDelegate> delegate;
Now you can use the delegates method to swap a view for another given that everything has been initialized right. the code to swap two controllers view could look like this
NewViewController *viewController=...
//you can set up your viewControllers data here if you need to
//Since its probable that this view has that data it can just set it instead of
//delegating
viewController.delegate=delegate; //setting up the RootViewController reference
[delegate toggleView:viewController viewController:self];
remember on the toggleView call back to release the old ViewController, if you dont youll get a leak since you lose all reference to that controller.
I have a viewController (Planner) that loads two view controllers (InfoEditor and MonthlyPlan) when the application starts. MonthlyPlan is hidden behind InfoEditor (on load).
So my question is when I exchange InfoEditor for MonthlyPlan (MonthlyPlan gets brought to the top) how can I have data on the MonthlyPlan view be updated. An NSLog in viewDidLoad is being called when the application starts (which makes sense.) NSLogs in viewDidAppear and viewWillAppear aren't doing anything.
Any ideas?
Thanks!
-- Adding more details --
I'm creating the view hierarchy myself. A simple viewController that is just loading two other viewControllers. The two child viewControllers are loaded at the same time (on launch of application.) To exchange the two views I'm using this code:
[self.view exchangeSubviewAtIndex:1 withSubviewAtIndex:0];
The exchanging of the views is fine. The part that is missing is just some way of telling the subview, you're in front, update some properties.
There's a lack of details here. How are you "exchanging" the two views?
If you were using a UINavigationController as the container then viewWillAppear/viewDidAppear would be called whenever you push/pop a new viewController. These calls are made by the UINavigationController itself. If you ARE using a UINavigationController then make sure you have the prototypes correct for these functions.
- (void)viewWillAppear:(BOOL)animated
If you are trying to implement a view hierarchy yourself then you may need to make these calls yourself as part of activating/deactivating the views. From the SDK page of viewWillAppear;
If the view belonging to a view
controller is added to a view
hierarchy directly, the view
controller will not receive this
message. If you insert or add a view
to the view hierarchy, and it has a
view controller, you should send the
associated view controller this
message directly.
Update:
With the new details the problem is clear: This is a situation where you must send the disappear/appear messages yourself as suggested by the SDK. These functions are not called automagically when views are directly inserted/removed/changed, they are used by higher-level code (such as UINavigationController) that provides hierarchy support.
If you think about your example of using exchangeSubView then nothing is disappearing, one view just happens to cover the other wholly or partially depending on their regions and opacity.
I would suggest that if you wish to swap views then you really do remove/add as needed, and manually send the viewWillAppear / viewWillDisappear notifications to their controllers.
E.g.
// your top level view controller
-(void) switchActiveView:(UIViewController*)controller animated:(BOOL)animated
{
UIController* removedController = nil;
// tell the current controller it'll disappear and remove it
if (currentController)
{
[currentController viewWillDisapear:animated];
[currentController.view removeFromSuperView];
removedController = currentController;
}
// tell the new controller it'll appear and add its view
if (controller)
{
[controller viewWillAppear:animated];
[self.view addSubView:controller.view];
currentController = [controller retain];
}
// now tell them they did disappear/appear
[removedController viewDidDisappear: animated];
[currentController viewDidAppear: animated];
[removedController release];
}
I would just add an updataData method to each subview and call it at the same time you bring it to the front. You would need to add a variable to your root view controller to track the active subView:
[self.view exchangeSubviewAtIndex:1 withSubviewAtIndex:0];
if (subView1IsActive) [subView1Controller updateData];
else [subView2Controller updateData];
I am not using a tab bar or any other control -- I want to basically change the current view to a different view controller dynamically (i.e. via code). I'm not using Interface Builder at all...
For example, let's say we create three view controllers:
(this may not be the best example, but I'm trying to make it simplistic)
View_Hello.m (and .h)
View_Goodbye.m (and .h)
View_Ciao.m (and .h)
Our ViewerAppDelegate would launch View01_Hello.
View_Hello would have a custom touch method that would then need to go to View_Ciao if swiped, but View_Goodbye if just touched.
Any ideas on how I could do this (and please don't say "oh, you need to use xxx interface element for this example". I need to be able to randomly change views based on programatic control within the view of the application I'm working on)
I'm been surfing through Google and StackOverflow for the past week, and gone through my three O'Reilly Cocoa books (plus three iPhone developer books), and all of them just use simple interfaces -- but nothing shows an example like what I'm trying to do.
===========
Edit (#Andrew Grant):
for example:
View_Ciao *viewCiao;
-(void) viewDidLoad {
viewCiao = [[View_Ciao alloc] initWithNibName:#"View_Ciao" bundle:nil];
[viewCiao.view setNeedsDisplay];
[super viewDidLoad];
}
This crashes. :-)
=============
Edit (#Daniel Dickison)
Brilliant -- that worked!
- (void)applicationDidFinishLaunching:(UIApplication *)application {
[window addSubview:viewController.view];
[window makeKeyAndVisible];
// create the second view, remove the first, and then display the second
viewCiao = [[ViewCiao alloc] init];
[viewController.view removeFromSuperview];
[window addSubview:viewCiao.view];
}
Have you seen recipe 2-8 "Swiping Views" in Erica Sadun's iPhone Developer's Cookbook? She uses touchesBegan and touchesMoved to determine swipe direction, then sets the animation based on the direction in touchesEnded.
You could extend or amend this to add tap detection in order to determine which view to transition to. The recipe is on or around page 69 if you'd like to have a look, anyway. There's also a video (mov) sample here and a code sample here.
How about something like:
#interface AppDelegate : ...
{
View_Hello *hello;
View_Goodbye *goodbye;
View_Ciao *ciao;
UIViewController *currentView;
UIWindow *window;
}
... IBOutlet properties for the 3 controllers.
#end
#implementation AppDelegate
- (void)switchToGoodbye
{
[currentView.view removeFromSuperview];
[window addSubview:goodbye.view];
currentView = goodbye;
}
... etc.
#end
You may need to resize the view before adding it to the window, and call viewWillDisappear:, viewDidDisappear:, viewWillAppear: and viewDidAppear: on currentView and the new view controller before and after they're removed/added.
Load the appropriate view and add it as a subview to the parent, then remove the existing view from its parent.
If you only have one level of views then your window is the parent.