My app has a map that tracks the user's location. This map will only appear under certain circumstances, and will dominate the user's attention until a particular task is complete, which is why the map isn't part of a navigation or tab bar UI.
If my map VC is set as the initial view controller in storyboard, it works fine. But if I try to load the map VC from elsewhere like this;
MapViewController *mapVC = [[MapViewController alloc] init];
[self presentModalViewController:mapVC animated:YES];
I just get a black screen.
I can confirm with NSLog that the VC is calling viewDidLoad and viewDidAppear, but the 'map' property of the VC is (null). I don't understand why (or how) I need to create the map property manually when using this technique, but it gets done for me when it is the initial VC.
The MapViewController instance in your storyboard is configured with a view hierarchy, including an MKMapView, and whatever else you did to configure that particular instance in the storyboard.
Now in this code which you show here, you are creating a completely new instance of MapViewController. It has no relationship to the instance in the storyboard other than they happen to be of the same class. So the one you create here with [[MapViewController alloc] init] has no view hierarchy (which is why you see a black screen), and none of the outlets or other configuration you may have made to the other MapViewController in your storyboard.
So what you want is to load that MapViewController that you've already set up from the storyboard. Assuming you are doing this from within a method in another view controller loaded from the same storyboard already, you can just do this:
// within some method on another vc from a scene in the same storyboard:
// given an identifier for the map view controller we want to load:
static NSString *mapVCIdentifier = #"SomeAppropriateIdentifier";
NSLog(#"Storyboard: %#",self.storyboard); // make sure this vc(self) was loaded from a storyboard
MapViewController *mapVC = [self.storyboard instantiateViewControllerWithIdentifier:mapVCIdentifier];
[self presentModalViewController:mapVC animated:YES];
And then back in the storyboard, just make sure you set the identifier for this map view controller to "SomeAppropriateIdentifier".
Hope that helps.
Related
Is it possible to embed (add as subview) a UITableViewController into another View Controller programmatically? I found a few answers here on StackOverflow but none worked for me with ARC and iOS6 SDK.
I know you can do this easily with Navigation and TabBar controllers but I am more curious about adding tableviews to a regular View controller. I need my tableview to occupy the lower part of the available screen space (I need the rest for other purposes, for which neither tab nor navigation types are suitable).
When I tried to do it, however, it did not work. I instantiated a subclassed UITableViewController, but when I added it to my self.view as a subview, the compiler said I tried to use "incompatible pointer types." Not only that, my instantiated UITableViewController does not have a .frame property, so I cannot set it dimensions, which would be the whole point of this exercise.
Building upon ogres answer, you should add the tableViewController's view as a subview, but it is not everything. The tableViewController is a viewController and it needs to know its parent and its children, to do its viewController-job correctly. I do not know any details here, but there is an entire talk about this from WWDC 2011 called "Implementing UIViewController Containment".
One problem I have experienced when only adding the view as a subview is that target actions don't seem to work. Tapping a UIButton or similar causes either a EXC_BAD_ACCESS or a unrecognized selector sent to instance.
So I recommend that you do something like this:
UIViewController *vc = //Your tableViewController
[self addChildViewController:vc]; //Important
[self.view addSubview:vc.view];
//If you want to set the frame, set the frame of the tableViewController's view
vc.view.frame = ...
yes , you can use tableview in another view without any problems
UITableViewController, but when I added it to my self.view as a subview
are you trying to add viewcontroller as subview or its view ? ( viewcontroller.view )
UITableViewController does not have a .frame property,
of course it does not have .frame property , it is a view CONTROLLER , you should see .view.frame
Just a simple question
Currently i present a modal view like this:
+ (void)showModalController:(id)ContentController InViewController:(UIViewController*)vc withFrame:(CGRect)rect{
UINavigationController *modalViewNavController = [[UINavigationController alloc] initWithRootViewController:ContentController];
modalViewNavController.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
modalViewNavController.modalPresentationStyle = UIModalPresentationFormSheet;
[vc presentModalViewController:modalViewNavController animated:YES];
//it's important to do this after presentModalViewController
modalViewNavController.view.superview.frame = rect;
//self.view assumes the base view is doing the launching, if not you might need self.view.superview.center etc.
modalViewNavController.view.superview.center = vc.view.center;
[modalViewNavController release];
}
I pass the values of the UIViewController Content that it will be presented, at a custom modal size. I also pass the values of the UIViewController where the modal it will be presented.
In terms of code, i want to know the "vc" name at the content class, if it's possible to do so.
EDIT
Lets say i have 2 classes, one is called DetailViewController where the modal will be presented. And the other one is called ModalContentViewController.
I want to know at the ModalContentViewController class (when the view appears, or is loaded) the name of the DetailViewController.
Any ideas?
PD: Currently Using...
XCode 4.4.1
iPad Simulator iOS5.1
iOS5.1
Look for the UIViewController property presentingViewController. Here's a quote from the docs:
If the view controller that received this message is presented by
another view controller, this property holds the view controller that
is presenting it. If the view controller is not presented, but one of
its ancestors is being presented, this property holds the view
controller presenting the nearest ancestor. If neither the view
controller nor any of its ancestors are being presented, this property
holds nil.
So you could use that property to get the presenting VC's name.
You can use NSStringFromClass(vc.class) to get the class name as an NSString.
I can't seem to figure this out for the life of me. I have a custom table view cell, in that cell I have a few buttons configured. Each button connects to other view controllers via a storyboard segue. I've recently removed these segues and put a pushViewController method in place. Transition back and forth across the various views works as expected however the destination view controller is not displaying anything! I have some code below as an example.
Buttons have this method set:
[cell.spotButton1 addTarget:self action:#selector(showSpotDetails:) forControlEvents:UIControlEventTouchUpInside];
// etc...
[cell.spotButton4 addTarget:self action:#selector(showSpotDetails:) forControlEvents:UIControlEventTouchUpInside];
// etc...
showSpotDetails Method contains this code:
- (void)showSpotDetails:(id)sender
{
// determine which button (spot) was selected, then use its tag parameter to determine the spot.
UIButton *selectedButton = (UIButton *)sender;
Spot *spot = (Spot *)[spotsArray_ objectAtIndex:selectedButton.tag];
SpotDetails *spotDetails = [[SpotDetails alloc] init];
[spotDetails setSpotDetailsObject:spot];
[self.navigationController pushViewController:spotDetails animated:YES];
}
The details VC does receive the object data.
- (void)viewDidLoad
{
[super viewDidLoad];
NSLog(#"spotDetailsObject %#", spotDetailsObject_.name);
}
The NSLog method below does output the passed object. Also, everything in the details view controller is as it was. Nothing has changed on the details VC. It just does not render anything ever since I removed the segue and added the pushViewController method. Perhaps I am missing something on the pushViewController method? I never really do things this way, I try to always use segues...
Any suggestions?
Welcome to the real world. Previously, the storyboard was a crutch; you were hiding from yourself the true facts about how view controllers work. Now you are trying to throw away that crutch. Good! But now you must learn to walk. :) The key here is this line:
SpotDetails *spotDetails = [[SpotDetails alloc] init];
SpotDetails is a UIViewController subclass. You are not doing anything here that would cause this UIViewController to have a view. Thus you are ending up a with blank generic view! If you want a UIViewController to have a view, you need to give it a view somehow. For example, you could draw the view in a nib called SpotDetails.xib where the File's Owner is an SpotDetails instance. Or you could construct the view's contents in code in your override of viewDidLoad. The details are in the UIViewController documentation, or, even better, read my book which tells you all about how a view controller gets its view:
http://www.apeth.com/iOSBook/ch19.html
The reason this problem didn't arise before is that you drew the view in the same nib as the view controller (i.e. the storyboard file). But when you alloc-init a SpotDetails, that is not the same instance as the one in the storyboard file, so you don't get that view. Thus, one solution could be to load the storyboard and fetch that SpotDetails instance, the one in the storyboard (by calling instantiateViewControllerWithIdentifier:). I explain how to do that here:
http://www.apeth.com/iOSBook/ch19.html#SECsivc
This one is probably something simple, still learning the ins-and-outs on this but I've run out of searches for this one with no available answer.
I've got a UIViewController with several elements displayed on it, one such element is a UITableView. The UITableView has it's own class and is allocated in the UIViewControllers viewWillAppear
- (void)viewWillAppear:(BOOL)animated
{
UITableView *insideTableView = [[UITableView alloc] init];
tableView.delegate = insideTableView;
tableView.dataSource = insideTableView;
}
Everything is working fine in regards to the tableview. Today I am experimenting with a few additions, one of which is a new view popup on cell selection within that tableview.
Inside my TableView Class, I have the following:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"Cell Pressed, Present View");
PopupView *popupView = [[PopupView alloc] initWithNibName:#"PopupView" bundle:nil];
popupView.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentModalViewController:popupView animated:YES];
}
Now it gets called fine, verified by the NSLog, however the view doesn't appear. I know the problem is related to the fact that I want PopUp to appear over the TableViews Parent rather than itself.
I'm just not sure how to properly call it in this instance.
The delegate is a UIViewController which doesn't have its view property set, which is why presentModalViewController:: doesn't work.
You need the view controller containing the table view to present the modal view controllers, but note that that view controller is not the parent of the table view delegate. This is because you have no view controller hierarchy in place.
The easiest way to fix this is to put those methods inside the view controller whose view contains the table view. Alternatively the table view delegate needs to hold a reference to the view controller so it can call presentModalViewController:: on it.
The latter approach can lead to retain cycle, so you have to use a non-retaining reference. The nicest implementation is the delegate pattern.
Also, you don't want to do the instantiation in viewWillAppear: because that can be called multiple times during the lifecycle of a view controller. Put the code in viewDidLoad and balance it in dealloc. Right now you are leaking memory every time your view appears, which when your modal view controller is working will be every time the modal view controller is presented and dismissed.
I'm designing a simple Quiz application. The application needs to display different types of QuizQuestions. Each type of QuizQuestion has a distinct behavior and UI.
The user interface will be something like this:
alt text http://dl.getdropbox.com/u/907284/Picture%201.png
I would like to be able to design each type of QuizQuestion in Interface Builder.
For example, a MultipleChoiceQuizQuestion would look like this:
alt text http://dl.getdropbox.com/u/907284/Picture%202.png
Originally, I planned to make the QuizQuestion class a UIViewController. However, I read in the Apple documentation that UIViewControllers should only be used to display an entire page.
Therefore, I made my QuizController (which manages the entire screen e.g. prev/next buttons) a UIViewController and my QuizQuestion class a subclass of UIView.
However, to load this UIView (created in IB), I must[1] do the following in my constructor:
//MultipleQuizQuestion.m
+(id)createInstance {
UIViewController *useless = [[UIViewController alloc] initWithNibName:#"MultipleQuizQuestion" bundle:nil];
UIView *view = [[useless.view retain] autorelease];
[useless release];
return view; // probably has a memory leak or something
}
This type of access does not seem to be standard or object-oriented. Is this type of code normal/acceptable? Or did I make a poor choice somewhere in my design?
Thankyou,
edit (for clarity): I'd like to have a separate class to control the multipleChoiceView...like a ViewController but apparently that's only for entire windows. Maybe I should make a MultipleChoiceViewManager (not controller!) and set the File's Owner to that instead?
You're on the right track. In your QuizController xib, you can create separate views by dragging them to the xib's main window rather than to the QuizController's main view. Then you can design each view you need according to your question types. When the user taps next or previous, remove the previous view and load the view you need based on your question type using -addSubview on the view controller's main view and keep track of which subview is currently showing. Trying something like this:
[currentView removeFromSuperView];
switch(questionType)
{
case kMultipleChoice:
[[self view] addSubview:multipleChoiceView];
currentView = multipleChoiceView;
break;
case kOpenEnded:
[[self view] addSubview:openEndedView];
currentView = openEndedView;
break;
// etc.
}
Where multipleChoice view and openEndedView are UIView outlets in your QuizController connected to the views you designed in IB. You may need to mess with the position of your view within the parent view before you add it to get it to display in the right place, but you can do this with calls to -setBounds/-setFrame and/or -setCenter on the UIView.
Yeah, IB on iPhone really wants File's Owner to be a UIViewController subclass, which makes what you want to a bit tricky. What you can do is load the nib against an existing UIViewController instead of instantiating one using the nib:
#implementation QuizController
- (void) loadCustomViewFromNib:(NSString *)viewNibName {
(void)[[NSBundle mainBundle] loadNibNamed:viewNibName owner:self options:nil];
}
#end
That will cause the runtime to load the nib, but rather than creating a new view controller to connect the actions and outlets it will use what you pass in as owner. Since we pass self in the view defined in that nib will be attached to whatever IBOutlet you have it assigned to after the call.