I dont have a very good understanding on the topic, so please bear with me
I am trying to display a UIViewController inside another UIViewController. I feel like there aren't enough examples out there. I have read the documentation but being fairly new to iOS I am kind of lost.
Here is my problem: I can get the child UIViewController to appear inside the parent UIViewController but the child view is not displaying right.
Sorry, I cant post pictures yet.
Here is my child - UIViewController.
Here is my parent - UIViewController. (The blue area is where the child view is added)
Here are the results:
Blue UIView in place - http://i.imgur.com/4vny8EZ.png
If i move the blue UIView over to the right here is what happens
Blue UiView moved over to the right - http://i.imgur.com/XCOBwr6.png
I have tried a lot of different things but my lack of knowledge on the subject is really making it difficult to find out what is wrong.
Here is how I am loading my child UiViewController in my parent UIViewControllers class:
- (void)viewDidLoad
{
[super viewDidLoad];
// Add Calculations View Controller
CalculationViewController *calculationController = [self.storyboard instantiateViewControllerWithIdentifier:#"Calculate"];
[self addChildViewController:calculationController];
calculationController.view.frame = self.calcualtionView.bounds;
[self.calcualtionView addSubview:calculationController.view];
}
So, my question is why is it displaying the child view in a weird fashion?
Thank you!
Also, sorry about the links I could only post two.
Quick answer: Views sizes aren't determined until viewWillAppear. Set the frame there and it will work.
Longer answer:
1) If you are using iOS6, I would encourage you to use NSLayoutConstraints to deal with view size and positioning rather than manually setting view frames. It takes a bit to really wrap your head around constaints, but once you do they are much more powerful and flexible than setting frames and you won't have to worry about when or how your IBOutlets are created
2) You are not adding your child view controller correctly. You must call didMoveToParentViewController: after the view is added. With the missing line of code as well as using contraints rather than frames your code looks like this:
CalculationViewController *calculationController =
[self.storyboard instantiateViewControllerWithIdentifier:#"Calculate"];
calculationController.translatesAutoresizingMaskIntoConstraints = NO;
[self addChildViewController:calculationController];
[self.calcualtionView addSubview:calculationController.view];
[calculationViewController didMoveToParentViewController:self];
// Add constraints for the view to fill calculationView
UIView *calcView = calculationController.view;
NSDictionary *viewsDictionary = NSDictionaryOfVariableBindings(calcView);
NSArray *hConstraint =
[NSLayoutConstraint constraintsWithVisualFormat:#"H:|[calcView]|"
options:0 metrics:nil
views:viewsDictionary];
[self.calculationView addConstraints:hConstraint];
NSArray *vConstraint =
[NSLayoutConstraint constraintsWithVisualFormat:#"V:|[calcView]|"
options:0 metrics:nil
views:viewsDictionary];
[self.calculationView addConstraints:vConstraint];
Move the code to viewDidAppear. If calculationView is an IBOutlet to a view, its bounds will be zero in viewDidLoad. The frames of views are not set until viewDidAppear.
Related
I am trying to just do a simple view change for proof of concept.
here is the code
- (void)swipedScreen
{
if (self.secondView.superview == nil) {
[myView removeFromSuperview];
[self.view insertSubview:secondView atIndex:0];
}
}
when I swipe the screen what happens is the view area just goes black... and becomes unresponsive.
I started with a navigatoin app, replaced the tableview with just a standard uiviewcontroller class.. that worked fine..Then i added a secondView (xib only) and changed its class to match the viewcontroller of the first view.
The reason I am finding this difficult is because i am trying to animate the views inside the navigation controller and not push a whole view onto the stack which I am used to doing.
I'll bet that blank unresponsive view is, in reality, your secondView object. I always test by setting [secondView setBackgroundColor:[UIColor greenColor]] and checking if the massive green rectangle actually shows up.
EDIT: having looked at your code, there are multiple problems that arose:
You never actually +alloc or -init anything.
You never actually touch those nibs or make a reference to them in code
You declare two UIView's as IBOutlets and Strong (two exact opposites, as IBOutlets are __weak, __unsafe_unretained, or assign), yet do not link them to anything.
I've taken the liberty of revising it (sans nibs). Take a look.
Did you init the secondView? if init,you can try to set frame for the secondView
Your inserting the view at the bottom of the stack,
[self.view insertSubview:secondView atIndex:0];
Try using addSubview instead. Also you need to set the views frame somewhere.
I am pretty new to iPhone programming, and was playing around with an app yesterday trying different scenarios with view controllers and nib files. So, I started a new app with a FirstViewController (FVC for short) and an FVC.xib.
I layed out a quick view in FVC.xib and ran the app - view displays, great.
I now wanted to have a second view I could add on top of the main view. So I went ahead and created SecondViewController.xib (SVC) but did not create the .m and .h files. I went about trying to load both these views from the same view controller, and here is where my question lies:
I created a button in FVC.xib and created an IBAction like this:
- (IBAction)loadSVC {
FirstViewController *viewController = [[FirstViewController alloc] initWithNibName:#"SecondViewController" bundle:[NSBundle mainBundle]];
secondView = viewcontroller.view;
[viewController release];
[self.view addSubView:secondView];
}
So this works great and adds the contents of SVC.xib, but when I try and remove that view from the superview, the app crashes:
[secondView removeFromSuperview];
If I actually create a view controller for SVC, use that to instantiate my view in FVC, and move the remove code to the SVC:
[self.view removeFromSuperview];
Everything works. My question - I kind of get why my first method crashes, but I was hoping someone could explain why and what goes on behind the scenes. I'm still a noob with object oriented programming, so what is actually happening in my first case where I create a new instance of FirstViewController and add its view to self.view? Why can't I release it (I assume because the original view is associated with FirstViewController, and when I create a new instance with the second xib it messes everything up) - I'd love a more technical explanation as to what is happening...
Thanks much!!
EDIT to add more info in response to Nick's reply below
Nick - so your answer did clear my thinking a bit in regards to the retain count, etc... I did another test app trying to get this working from a single view controller - think, for example, that I wanted to display an Alert or Welcome message to the user (I know in a real app there are different methods to accomplish this, but this is more of a learning experience) -- so I have my main view # MainViewController and layout my alert message in a xib called alert.xib -- so there is no logic behind the alert message, no reason for it to have a view controller that I can see, my end goal being loading/unloading this on top of my main view from the main view's view controller (or understanding why it is impossible)
I tried this using instance variables as you recommended:
In MainViewController.h:
#import <UIKit/UIKit.h>
UIViewController *secondController;
UIView *secondView;
#interface MainViewController : UIViewController {
}
#property(nonatomic, retain) UIViewController *secondController;
#property(nonatomic, retain) UIView *secondView;
- (IBAction)loadSecond;
- (IBAction)removeSecond;
#end
In MainViewController.m:
#import "MainViewController.h"
#implementation MainViewController
#synthesize secondController, secondView;
- (IBAction)loadSecond {
secondController = [[MainViewController alloc] initWithNibName:#"alert" bundle:[NSBundle mainBundle]];
secondView = secondController.view;
[self.view addSubview:secondView];
}
- (IBAction)removeSecond {
//I've tried a number of things here, like [secondView removeFromSuperview];, [self.secondView removeFromSuperview];, [secondController.view removeFromSuperview];
}
- (void)dealloc {
[secondController release];
[secondView release];
[super dealloc];
}
So - this works to load the alert view, but the removeSecond button does nothing (I did use NSLog to verify the removeSecond method is fired) - why?
Second, and most importantly - is this even possible, or is it horrible practice? Should every nib/view I am manipulating have their own view controller? Am I wrong to think I could just make a new instance of MainViewController and use it to display and remove this no-functionality, very temporary view? (And yes, I realize I could easily create this view programatically or accomplish the end goal in many different ways which would be easier, but I'm trying to really learn this stuff and I think figuring this out will help...
Thanks for the help!
You created a view controller
You accessed its view which caused controller to create the view and call the delegates (i.e. viewDidLoad)
Controller returns the view that you asked for
Now you add the view as a subview which increases its retain count
Controller is released and it releases the view, BUT since view's retain count was increased the view is still there
You try to remove the view, it is unloaded and delegates are to be called (e.g. viewDidUnload), however that messes up since the controller who created the view is released and that piece of memory is... smth else :)
That's why the first method doesn't work.
The second method is NOT correct either but it works because:
You remove controller's view from superview but since controller itself is not released (you didn't call [self release] or anything like that, not saying that you should :), just an example), then the view didn't reach 0 (zero) retain count and is still there - which means its subviews aren't removed
The proper way to do it is to save the reference to the controller as an instance variable (usually declare a synthesized property), and release it only when you are done with the view, making sure that the view is removed from superview before hand. The default templete for a View Based App shows how view controller should be managed
Hope this helps to understand why both methods behave differently
Based on your clarifications, you don't need secondView property or iVar. Also in your loadSecond instead of secontController = bla you need self.secondController = bla, otherwise you simply assign reference to the iVar instead of going through the setter.
Yes, it's possible to load subviews/other resources from a nib without having a dedicated controller
This is how you do it (one of the approaches):
UIView *result = nil;
NSArray *bundle = [[NSBundle mainBundle] loadNibNamed:#"MyNibName" owner:owner options:nil];
for ( id o in bundle ) {
if ( [o isKindOfClass:[UIView class]] ) {
result = (UIView *)o;
break;
}
}
Here the result will contain the first UIView in MyNibName. You can use other criteria to find out whether you got the view you wanted (tags, types...)
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?
I have a problem, using presentModalViewController to display a UIView. Within the Application I have a NavigationController with a list of Items. Touching a Cell calls the first ViewController, responsible for only showing a background picture. Within the viewDidLoad method I create another ViewController which has a UiScrollView, displaying some information about the item.
So far so good.
Now, an item can consist of subitems, so if I click on a subitem, I use presentModalViewController to create a new instance of the first ViewController. My problem is, that this newly displayed controller is show around 180px(a guess) lower than it should be. I thought, this was due to relative coordinates I set wrong, but if I click on a subitem with the new (lower) controller, I would expect it to be displayed lower again (say 360px) - relative to the topleft corner of the Iphone.
Anyway, this doesnt happen. My question is why is the new controller displayed lower than it should be/I expect it to be. Spent a few hours on this, so any ideas are appreciated!
Edit: Some Code - this is the part, where i present the controller:
ItemDetailsViewController *itemScrl= [[ItemDetailsViewController alloc] initWithNibName:#"ItemDetailsViewController" bundle:nil];
itemScrl.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentModalViewController:itemScrl animated:YES];
This is the part, where I create the scrollable View:
- (void)viewDidLoad {
[super viewDidLoad];
ItemScrollController *itemScrl = [[ItemScrollController alloc] initWithNibName:#"ItemScrollController" bundle:nil];
itemScrl.title = self.title;
itemScrl.view.frame = CGRectMake(20 , 0, 280, 400);
[self.view addSubview:itemScrl.view];
}
I think my problem was, not having added a Navigationbar in the parentviewController and not telling the subview, that there actually was one. There are various ways to do this, I suppose, anyways, in IB you can checkmark the Navigationbar box for the actual view and thus it shouldnt be resizing anything.