Best way to call method that exists in multiple classes - iphone

I have a main UIViewController where most of the users' interaction happens. In the main ViewController there are three subviews. The user can load separate ViewControllers into the UIView subviews.
Each of the subviews that are loaded deal with data entry. In turn, firstResponders are called. I would like to be able to dismiss the firstRespnders through the main ViewController, maybe with a 'Done' button.
I was thinking I could add a method in each of the separate subviews with one name ex;
-(void) methodToResignResponders {}
Then, in the main ViewController call this method to the view that is currently open to the user. In turn resigning the responders that are active in the subview.
Further Information:
This is how I set up each view as a subview of the main ViewController:
UIViewController *calcVC;
//set up the view to be added depending on the name of the view that was passed
if ([viewName isEqualToString:#"Tax"]) {
calcVC= [[TAXViewController alloc]initWithNibName:#"TAXViewController" bundle:nil];
}else if ([viewName isEqualToString:#"Rent"]){
calcVC= [[RENTViewController alloc]initWithNibName:#"RENTViewController" bundle:nil];
}else //continues with more views...
//Then add it to the subview
[firstView addSubview:calcVC.view];

Not sure if I've got the gist of this, mostly because it sounds like you've already solved it yourself. :)
But, from what I can see the ViewController you are talking about is always an UIViewController instance named calcVC. If it is always this viewController's view you are referring to you can simply call [calcVC.view resignFirstResponder];

You can make a basic protocol that all of your sub-view controllers implement that has does everything you need (resign first responder and anything else).

Not sure if this answers your question but you can loop through all the subviews and call it if it exists as follows:
for (UIView *subview in [self.view subviews]) {
if ([subview respondsToSelector:#selector(resignFirstResponder)]) {
[subview resignFirstResponder];
}
}

Related

TouchesBegan on a Sub-ViewController not getting called

I have a ViewController that responds to some touchEvents (touchesBegan, touchesMoved, etc...).
I've found that when I show this controller using presentModalViewController: it works just fine, but I'm trying to add it's View as a subview of another ParentViewController like so:
- (void)viewDidLoad
{
[super viewDidLoad];
//Add SubController
controller = [[SubViewController alloc] initWithNibName:#"SubViewController" bundle:nil];
controller.view.frame = CGRectMake(0, 30, 300, 130);
[view addSubview:controller.view];
[controller release];
}
When I do this, it gets added the parent view but it no longer responds to touch events. Is there a way to fix this?
Also, is there a better way to go about this? I know I probably could have used a View subclass for the child view, but it's supposed to use a Nib and I wasn't sure how to handle that without using a ViewController.
You're correct you should use a UIView subclass.
The easiest way to load it from a nib is to include the subview in your nib.
Just drop a UIView into the view connected to the original view controller.
Then with the view inside selected go to the identity inspector. It's the one that looks like a little ID card.
The very first field is called Custom Class.
Type the name of your UIView subclass here.
If you need a reference to this just create an IBOutlet in your original view controller and hook it up. That way you can set hidden = YES until you need it.
In your UIView subclass you might want to override
- (void)awakeFromNib
This will get called when the nib first unpacks.
for setting up any gesture recognizers, etc.
To load a nib directly into a view :
// Get the views created inside this xib
NSArray *views = [NSBundle mainBundle] loadNibNamed:#"myViewNib" owner:nil];
// There's probably only one in there, lets get it
UIView *myView = [views objectAtIndex:0];
// Do stuff . . .
[[self view] addSubview:myView];
You could try to call becomeFirstResponder in your subview and see whether it receives touchesBegan... It is probably so, but it will also possibly make the superview not receive touchesBegan if you require it...

Calling method in parent UIViewController, after adding by addSubview

I have a UIViewController that is creating another view controller, and adding its view as a subview:
In the parent UIViewController:
SlateMoreView* subView = [[SlateMoreView alloc] initWithNibName:#"SlateMoreView" bundle:nil];
[self.view addSubview:subView.view];
I then need to call a method from the subview, in the parent view.
I have seen how to do this when I am adding the sub UIViewController using [self.navigationController pushViewController: subView animated: YES], because I can find the parent using this kind of code:
In the sub view UIViewController:
NSArray* viewControllerArray = [self.navigationController viewControllers]
int parentViewControllerIndex = [viewControllerArray count] - 2;
SlateView* slateView = [viewControllerArray objectAtIndex:parentViewControllerIndex];
...and then I can send messages to it. But since I added the sub view manually by using addSubView, I can't do this.
Can anyone think of how I can talk to my parent UIViewController?
Thanks!
UIViews have a superview property which seems to be what you are looking for.
In addition you probably don't want to nest UIViewController's view like that unless you are very deliberately building a custom contain view controller. See http://blog.carbonfive.com/2011/03/09/abusing-uiviewcontrollers/
You might want to consider if your problem can be solved by using NSNotifications. You could post a notification from your subview when an event happens that interested listeners (your superview) need to know about . When the superview receives the notification, it can run whatever code you wish. All the while the subview never needs to know about the superview.
This is one way to make your classes less dependant on each other.
You could also use delegation as another option.
When you add your view as a subview to a view hierarchy, you put it in the responder chain. You can go up the responder chain to reach the view controller as a UIView controlled by a UIViewController has the UIViewController as its nextResponder.
id object = theSubview;
do {
object = [object nextResponder];
} while ( ![object isMemberOfClass:[YourViewController class]] );
// object has the view controller you need.

iPhone, need the IF for dismissModalViewControllerAnimated ELSE removeFromSuperview?

I need to add this to my dismiss button :-
[self dismissModalViewControllerAnimated:YES];
[self release];
else
[self.view removeFromSuperview];
I thought
if( self.navigationController.modalViewController ) {
would work be it nevers true
A couple of things:
1) You shouldn't ever release yourself in an object. If you're presenting a modal view controller, you should perform the release there since the view controller will now be retained by the view controller's .modalViewController property:
(In the parent):
UIViewController *someViewController = [[UIViewController alloc] init];
[self presentModalViewController:someViewController animated:YES];
[someViewController release];
2) The parent will store its child modal view controller in .modalViewController. The child will have its .parentViewController property set in this case. If the view has been added as a subview, its .superview property will be set. These are not mutually exclusive, however, so be careful. Generally speaking, UIViewControllers are intended to host full-screen views, and if you're adding the view as a subview, you should ask yourself if the view should just be a UIView subclass, and move the logic into the parent view controller.
That said, I suppose you could check your case (assuming you don't present modal view controller and add as a subview simultaneously):
if (self.parentViewController) {
[self dismissModalViewControllerAnimated:YES];
} else if (self.view.superview) {
[self.view removeFromSuperview]
}
In the latter superview case, the view controller will still be hanging around, so you'd need to let the other view controller know via delegate method or something to release you. In the first case, if you have released the presented view controller already as I described above, it will be released automatically when the parent view controller sets its .modalViewController property to nil.
Normally for a "dismiss" button I would call a method in the controller that presented the modal controller (use a delegate), not try to dismiss the modal view controller from within itself. I don't quite get what youre trying to do though, but that [self release] looks bad. I don't think you ever want to release self like that.
Try this in you modal viewcontroller:
- (IBAction)close:(id)sender {
[self.parentViewController dismissModalViewControllerAnimated:YES];
}
Then just connect the button's action to that method.

Cancel out of UISearchBar when user taps on view

Does anyone know how to cancel (resign First Responder) out of a UISearchBar when you tap below the search text box and above the keyboard? Can anyone help post some code to handle this?
Thanks
Add a tap gesture in the parent view (of the UISearchbar)
[self addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:searchBar action:#selector(resignFirstResponder)]];
I accomplished this by using a UITapGestureRecognizer:
UIGestureRecognizer* cancelGesture;
- (void) backgroundTouched:(id)sender {
[self.view endEditing:YES];
}
#pragma mark - UISearchBarDelegate
-(void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar {
cancelGesture = [UITapGestureRecognizer new];
[cancelGesture addTarget:self action:#selector(backgroundTouched:)];
[self.view addGestureRecognizer:cancelGesture];
}
-(void)searchBarTextDidEndEditing:(UISearchBar *)searchBar {
if (cancelGesture) {
[self.view removeGestureRecognizer:cancelGesture];
[cancelGesture release];
cancelGesture = nil;
}
}
The code is a bare, but you can see the intent. When the SearchBar starts editing, you attach a tap gesture recognizer to the view controller's view, and remove it when it stops editing.
There are a couple caveats that you can work around: doing this will make it so if you click anything besides the keyboard or the search bar's text field, the recognizer traps the click -- so if you use the clear, cancel, scope or results button they won't respond correctly.
In my particular scenario, I had a UITableView that was covering the exposed area of the view so I attached the gesture recognizer to it instead of the view controllers main view, isolating the area to which the gesture would respond.
An alternative idea I got from iphonedevbook, sample code project 04, was to use one big transparent button that lies behind all other controls which does nothing but resign all first responders if tapped. I.e. if the user taps anywhere where there isn't a more important control - which is the intuitive behavior - the search bar and keyboard disappear.
I ended up using a hybrid of Hauke's and Beau Scott's approach. There were two problems I ran into using their solutions:
1) If there's anything else on the screen, tapping it won't result in resignFirstResponder being called. For example, if the user taps a button rather than the space around the button, the button will eat the event. Beau Scott's solution addresses this issue, however.
2) Tapping the search bar itself will result in resignFirstResponder getting called. Clearly you don't want the keyboard to disappear when you tap UISearchBar. A small change described below addresses this.
I ended up setting up my view as follows. The parent view has two children - the UISearchBar and a subview which holds the rest of my UI elements. The subview takes up the entire screen below the UISearchBar. Then I used Beau Scott's exact code to add and remove the gesture recognizer, but instead of adding it to self.view I added it to the subview:
IBOutlet UIView *gestureRecognizer;
...
-(void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar {
cancelGesture = [UITapGestureRecognizer new];
[cancelGesture addTarget:self action:#selector(backgroundTouch:)];
[gestureRecognizer addGestureRecognizer:cancelGesture];
}
-(void)searchBarTextDidEndEditing:(UISearchBar *)searchBar {
if (cancelGesture) {
[gestureRecognizer removeGestureRecognizer:cancelGesture];
[cancelGesture release];
cancelGesture = nil;
}
}
First, you need a reference to the search bar. Let's assume that your controller object has an object reference UISearchBar *theSearchBar, and that you assign it when you create the UISearchBar object.
Next, you need to detect that the containing view has been touched. The view that is touched "knows", but you need get that information to the controller. Sadly, Apple didn't provide a simple way to do this, but it's not that hard either.
My solution is to replace the standard UIView that a UIViewController object normally creates with a UIControl, and then make the UIViewController respond to touch events.
MainController.m
- (void) loadView {
UIControl *control = [[UIControl alloc] initWithFrame: <desired frame>];
[control addTarget: self action: #selector(touchUpInside)
forControlEvents: UIControlEventTouchUpInside];
// or touch down events, or whatever you like
self.view = control;
[control release];
}
- (void) viewDidLoad {
[super viewDidLoad];
theSearchBar = [[UISearchBar alloc] initWithFrame: <desired frame>];
// insert code to finish customizing the search bar
[self.view addSubview: theSearchBar];
}
- (void) touchUpInside {
if [theSearchBar isFirstResponder] {
// grab any data you need from the search bar
[theSearchBar resignFirstResponder];
}
}
MainController.h
#interface MainController : UIViewController
{
UISearchBar *theSearchBar;
}
Clarification:
There is only a single object -- let's call the class MainController -- which is a subclass of UIViewController. All of the methods listed above are implemented in MainController. theSearchBar is declared as a UISearchBar* in the .h file.
Are you defining your view and controller using Interface Builder? If so, I suggest you learn how to NOT use it -- once you get into the kind of tricks we are discussing here, it becomes more of a hindrance than a help -- I don't use it at all, ever.
#Gia Dang's answer is the simplest, but I don't subclass the UIView, only the UIViewController, so my call is slightly different. Also, since I don't know the overhead for actually calling resignFirstResponder, I prefer to check first. It's more code, but since all of this is done on the main thread (which can slow down the UI), I'd rather check first.
#implementation MyController : UIViewController {
#private
UISearchController *_uiSearchController;
}
- (void)viewDidLoad {
// add tap on view to resign the responder if we're in the middle of typing in the search
UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(closeKeyboardIfNeeded)];
[self.view addGestureRecognizer:tapGestureRecognizer];
}
- (void)closeKeyboardIfNeeded {
if (![_uiSearchController.searchBar isFirstResponder]) {
return;
}
[_uiSearchController.searchBar resignFirstResponder];
}
#end
As for the other answers, be careful about constantly recreating objects. There is always a performance hit, whether it's the creation itself or the garbage collection through ARC, and these things will slow down your main thread. Depending on what you're doing also on the main thread, it may have a significant performance impact.

Update UIViewControllers after switching of the tabbar selection

I have two view controllers in a tabbar which can both edit data. Therefore, I need to call a reload_data function whenever the user makes a switch on the tabbar. How can I catch the switch or the appearance of the viewcontroller. Somehow viewDidAppear is not called on a tabbar switch. And I do not want to use the tabbarController delegate for this, because several viewControllers are affected (and I cannot set them all as delegate). What is a good way to solve this?
e.g. this didn't work:
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:YES];
[self reloadData];
}
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:YES];
[self reloadData];
}
If you're using Interface Builder, make sure the class for the viewController your expecting to reload is defined (Select the ViewController in IB, then CMD-4, make sure class is defined to be the class you want viewWillAppear and viewDidAppear to be called in).
If you're not using IB, post your code for init/calling the viewController.