I have a viewcontroller that can show several popovers. Not at the same time. Which would be the best way to know which popover is being dismissed at popoverControllerDidDismissPopover?
I have to do different actions regarding the popover that is being dismissed.
Thanks a lot
Something like this should work. (This code is not complete - I assume you know basic memory and class management and other stuff so I focus on the actual problem)
In your class keep some ivars to store reference to the popovercontrollers you created
#interface MyClass : NSObject <UIPopoverControllerDelegate> {
UIPopoverController *popover1;
UIPopoverComtroller *popover2;
}
Init your popovercontrollers as usual and save a referance to each of them in popover1 and popover2.
Then in your implementation of the UIPopoverDelegate protocol:
- (void)popoverControllerDidDismissPopover:(UIPopoverController *)popoverController {
if(popoverController == popover1) {
//popover1 was dismissed
} else if (popoverController == popover2) {
//popover2 was dismissed
}
}
EDIT: Looking at your comments, it seems that you mean that you are using only ONE popovercontroller, and replacing it's content view with different UIViewControllers.
If this is the case, I suggest you perform whatever the actions are inside those particular UIViewController in such a way that it affects your application´s state.
Then, once the popover is dismissed, you reload your original view with the new refreshed state.
Or you change it to use two different instances of UIPopoverController instead.
This is how in Swift as of Xcode 6.3 beta 3, should be similar in Objective-C.
Your presented view should have a ViewController for itself.
import UIKit
class MenuBookmarksViewController: UITableViewController {
}
Add an extension to the UIViewController class or place the code (below) inside the UIViewController that will be presenting your popovers:
extension UIViewController: UIPopoverPresentationControllerDelegate {
public func popoverPresentationControllerDidDismissPopover(popoverPresentationController: UIPopoverPresentationController) {
if popoverPresentationController.presentedViewController as? MenuBookmarksViewController != nil {
///do your stuff
}
}
}
You are passed which popover is being dismissed in popoverControllerDidDismissPopover:. Use that to determine what you want to do in each case.
You'll probably want to store your UIPopoverController instances as ivars of whatever object is presenting them, and then just compare against the value that you're passed in the delegate method.
Related
SettingsStore.h
#interface SettingsStore : IASKAbstractSettingsStore
{
#public
NSDictionary *dict;
NSDictionary *changedDict;
}
- (void)removeAccount;
#end
menuView.m
-(IBAction)onSignOutClick:(id)sender
{
SettingsStore *foo = [[SettingsStore alloc]init];
[foo removeAccount];
[self.navigationController pushViewController:foo animated:YES];
exit(0);
}
I want to call this removeAccount function from menuView.m. But I am getting error.
How to fix it and call this removeAccount.
There are few mistakes in your Code please find them below.
[foo removeAccount]; Calling this method is correct
[self.navigationController pushViewController:foo animated:YES];
Not correct because SettingsStore is not subclass of
UIViewController only subclass of UIViewController can be pushed to
Navigation controller
exit(0); Calling this method is not
recommended by Apple
You are calling removeAccount correctly from your menuView.m file, but there are several issues with your code:
You are treating foo as though it were a UIViewController, and it's actually a member of the SettingStore class. Does the SettingStore class refer to an actual screen, or is it more a data object (for storing settings?). If it's the latter, you don't want to push it on. You can create it, and use it, but the user doesn't need to see it.
You are calling exit(0); you can remove that line. If you want to remove the menuView.m file from your memory, remove references to it (e.g. from its parent view controller).
The menuView.m file is confusing, as in, is it a view or a viewController. An IBAction I would normally stick in a ViewController file, rather than a view file. Your basic design pattern is MVC (Model / View / Controller). In this case, it seems your SettingStore file is a Model (data), the menuView.m is a View and your code is for the Controller bit.
I have a custom class myCustomClass which is a subclass of UITextField. (I'm going to call myCustomClass in a viewControllers class.)
In myCustomClass, I'm trying to check what kind of viewController the class that called it is. (UIViewController, UITableViewController etc.)
I tried:
if ([self.superview.nextResponder isKindOfClass[UIViewController class]]) {
NSLog(#"View Controller");
} else if ([self.superview.nextResponder isKindOfClass[UITableViewController class]) {
NSLog(#"TableView Controller");
}
I only get a result if the superclass is a viewController. So I did the following:
NSLog(#"%#", self.superview.nextResponder);
Results
UIViewController Class - ViewController
UITableViewController Class - UITableViewCell
How can I check if it's a UITableViewController?
For your specific case, you can use [self.superView isMemberOfClass:[UITableViewCell class]] to check if your custom view is inside a table view cell, which (unless you are using tableViewCell in an unusual way!) means that it's being called from a UITableViewController.
More generally, if you wanted to find out the containing view controller, you can recursively walk up the responder chain to find the containing viewController as in the second answer in this post:
Get to UIViewController from UIView?
It's also important to note that there is a difference between isKindOfClass: and isMemberOfClass:
isKindOfClass returns YES if 'the receiver is an instance of given class or an instance of any class that inherits from that class.'
isMemberOfClass returns YES if ' the receiver is an instance of a given class.'
Therefore, your UITableViewController, which inherits from UIViewController, will answer YES to isKindOfClass:[UIViewController class], will your if statement to act unexpectedly. (Though in the example it also didn't work correctly because you still needed to walk up the responder chain further).
So, if you in fact are comparing a UIViewController to a UITableViewController use -isMemberOfClass and your logic in the example would work as expected.
Trying to get a better understand of iOS delegation. I'm using UIImagePickerController as a reference but what's a good code example to use a delegate to dismiss my view controller?
I have a TabBarViewController that calls AViewController and want to use delegation to dismiss AViewController.
In this case, the idea is that the class that presented the new viewcontroller, should also be the one that dismisses it. The AViewController may have no clue how it was presented, so it wants to let the presenter, the TabBarViewController, handle the dismissal in whatever form needed. So, we need to define a protocol, say AViewControllerProtocol, which allows there to be a standard definition of the dismissal call:
This goes in AViewControllerProtocol.h:
#protocol AViewControllerProtocol <NSObject>
#required
- (void) dismissWithDone:(UIViewController *)viewController;
- (void) dismissWithCancel:(UIViewController *) viewController;
#optional
- (void)dismissWithDone:(UIViewController *)viewController andPlaySoundFile:(NSString *)soundPath;
#end
This goes in a file called AViewControllerProtocol.h. Both TabBarViewController.m and AViewController.m will import it. Think of this as a pact that any user of AViewController must agree to before it can utilize it. Similarly, you can't use UITableView without making a pact to observe the UITableViewDelegate and UITableViewDataSource protocols (those are two separate protocols).
Any class which wants to present AViewController, can see from the protocol definition that AViewController expects two required methods in order to be properly dismissed. It also has an optional third method that requests the presenter to play a sound after dismissing.
In order for AViewController to do its piece of this pact, it needs to get and store one piece of information about who the presenter is. That is called the delegate. The delegate is a property defined in the #interface of AViewController, in AViewController.h:
This goes in AViewController.h:
#property (nonatomic, weak) id<AViewControllerProtocol> delegate;
Now, the presenter, TabBarViewController, needs to do its bit. It needs to define the two required methods, plus maybe the optimal one, and it also needs to set the delegate value:
In TabBarViewController.m, in the #implementation:
This goes in TabBarViewController.m:
- (void) dismissWithDone:(UIViewController *)viewController
{
[self saveData:viewController.dataToSave]; // this could be the results that need to be saved
[viewController dismissViewControllerAnimated:YES completion:^{
;
}];
}
- (void) dismissWithCancel:(UIViewController *)viewController
{
// don't save data
[viewController dismissViewControllerAnimated:YES completion:^{
;
}];
}
The delegate value is set where AViewController is first created and/or before it is presented:
This also goes in TabBarViewController.m:
AViewController * aVC = [AViewController.alloc init];
aVC.delegate = self;
aVC.data = ...; // this may be the data you want changed by the VC
[self presentViewController:aVC animated:YES completion:^{
}];
Setting the delegate here is the only connection that the AViewController class has with its presenting viewController - which is the whole point here: child classes really shouldn't have to know a whole lot about the classes that utilize them.
Lastly, the AViewController class needs to add the following in order to call, via the delegate, back to the presenting class - so in AViewController.m:
This goes in AViewController.m:
-(IBAction)userHitButton:(id)sender
{
if (sender == doneButton) {
if ([_delegate respondsToSelector:#selector(dismissWithDone:)]) {
[_delegate dismissWithDone:self];
}
} else {
if ([_delegate respondsToSelector:#selector(dismissWithCancel:)]) {
[_delegate dismissWithCancel:self];
}
}
}
If you are wondering why the calling class has to:
aVC.delegate = self;
It is because there are situations where the class that actually creates a child class, isn't the one that will handle the delegate calls. In that case, instead of self, you put an instance of a class that will handle the delegate callbacks. For example, lets say that you have AViewController, BViewController and CViewController. They all get data from the user that needs to be saved. A class by the imaginary name of ABCDataHandler could be the one that can handle the dismissWithDone: and dismissWithCancel: callbacks and saves the data as needed, and TabBarViewController can stay out of any data handling activity.
That's to put it as simply as I can. I hope I haven't made any typos here :-)
I am making master detail application, i have dynamic Detail ViewController. Detail ViewController are changed.
But in every Detail ViewController I have one common method updateInfo I want to call that method
Here is my code
UINavigationController *nav=[self.splitViewController.viewControllers objectAtIndex:1];
UIViewController *controller=[nav.viewControllers objectAtIndex:0];
[controller updateLastInfo];
But it gives me error no method found.
it will work if i use UIViewController name.
HomeViewController *controller=(HomeViewController)[nav.viewControllers objectAtIndex:0];
[controller updateLastInfo];
But i dnt want to do above things.
I have tried to explain. Please help
You can use id
UINavigationController *nav=[self.splitViewController.viewControllers objectAtIndex:1];
id controller=[nav.viewControllers objectAtIndex:0];
[controller updateLastInfo];
You could subclass UIViewController and make a base DetailViewController class that houses common functionality of your detail view controllers. Then you would make all of your detail view controllers subclass DetailViewController instead of UIViewController. This would be a safe way to do it and would also allow you to add extra functionality to your updateInfo method in the specific detail view controllers.
If you want an unsafe way, you could make your controller object of type id. I wouldn't suggest this approach as it relies on your personal knowledge of the code. If someone else (or yourself down the road) sets it to a view controller that doesn't have that method, the code will still try to run and will crash.
UIViewController doesn't have a method named updateInfo, so the compiler will of course complain when you try to send that message to a pointer that's known only to point to an instance of UIViewController. When you use the class name, like this:
HomeViewController *controller=(HomeViewController)[nav.viewControllers objectAtIndex:0];
you're providing more information to the compiler, using a type cast to tell it "Hey, don't worry, I know for certain that the object I'll get back is a HomeViewController. Since you seem to have several types of view controllers that all have this method, the best thing to do is to declare the updateInfo method in a protocol and then have each of those UIViewController subclasses implement that protocol. So, your protocol declaration would be in a header file and might look like:
#protocol SomeProtocol
- (void)updateInfo
#end
and each class that has an -updateInfo method would just need to declare that it adopts the protocol:
#interface HomeViewController <SomeProtocol>
//...
#end
and then make sure that you have an -updateInfo in your class implementation:
#implementation HomeViewController
- (void)updateInfo {
//...
}
//...
#end
Then, in your code, you can either check that the object conforms to the protocol using -conformsToProtocol: like this:
if ([controller conformsToProtocol:#protocol(SomeProtocol)]) {
UIViewController<SomeProtocol> *c = (UIViewController<SomeProtocol>*)controller;
[c updateInfo];
}
or else just check that the object responds to the selector before calling it:
if ([controller respondsToSelector:#selector(updateInfo)]) {
[controller performSelector(updateInfo)];
}
The other answers you've received (using id or creating a common base class) are also good ones, but to be safe make sure you do some checking before calling your method. For example, you can use -isKindOfClass to make sure that the view controller you get back is in fact an instance of your common base class, and you can use -respondsToSelector: as above to check that an id points to an object that implements updateInfo.
I have several popovers in my application and I am having difficulty in determining which popover was dismissed. Is there a "tag" feature equivalent for UIPopOvers?
I can NSLog the popoverController in the popoverContorllerDidDismissPopover method and see the memory reference of each one but that doesn't help.
#pragma mark - Popover controller delegates
- (void)popoverControllerDidDismissPopover:(UIPopoverController *)popoverController {
NSLog(#"Popover dismised %#", popoverController);
}
An extract from here:
If I understand the question, then basically, no - and it's maddening.
On the one hand you're told that only one popover should be showing at
any one moment. On the other hand you don't automatically get a
reference to that popover. Thus it is up to you to store a reference,
manually, to the current popover controller at the time it shows its
popover, so that you can talk to it later in order to dismiss it.
Popover controller management can thus get really elaborate and
clumsy; you're doing all kinds of work that the system should just be
doing for you.
iOS is funny this way. I'm reminded of how there's no call in iOS 4
that tells you current first responder. Obviously the system knows
what the first responder is, so why won't it tell you? It's kind of
dumb. This is similar; the system clearly knows useful stuff it won't
share with you. m.
There are many ways how to distinguish between popovers. I will list few of them:
You are asking about tag. Note that every popover has a content view controller and this controller has a view that can be tagged. However, using magic integer tags to distinguish between views is arguable in general.
Store the type of the popover into a variable/property in your controller, e.g. as an enum. This is the simplest way.
Add the neccessary information to the popover, but be clever about it, e.g.
#interface MyPopoverController : UIPopoverController
#property (nonatomic, copy, readwrite) void (^dissmissHandler)(void);
#end
#implementation MyPopoverController
- (id)initWithContentViewController:(UIViewController*)contentView {
self = [super initWithContentViewController:contentView];
if (!self) {
return nil;
}
self.delegate = self;
return self;
}
- (void)popoverControllerDidDismissPopover:(UIPopoverController*)popover {
assert(popover == self);
if (self.dissmissHandler) {
self.dissmissHandler();
}
}
#end
MyPopoverController* popover = [MyPopoverController alloc] initWithContentViewController:...];
popover.dissmissHandler = ^{
...
};
As #Anoop stated, you can usually only have one popover showing at a time.
One possible solution is to check the contentViewController property on the pop over. If you are storing a reference of each view controller you could do something like:
- (void)popoverControllerDidDismissPopover:(UIPopoverController *)popoverController {
if ( popoverController.contentViewController == self.someUIViewController ) {
// do stuff
}
else if ( popoverController.contentViewController == someoTherViewController ) {
//
}
NSLog(#"Popover dismised %#", popoverController);
}
If storing a reference to each content view controller is not possible (or maybe just not a good idea), you could always check its type:
- (void)popoverControllerDidDismissPopover:(UIPopoverController *)popoverController {
if ( [popoverController.contentViewController isKindOfClass:[MyAwesomeViewController class]] ) {
// do stuff
}
else if ( [popoverController.contentViewController isKindOfClass:[MyOtherViewController class]] ) {
//
}
NSLog(#"Popover dismised %#", popoverController);
}
Another possible solution, which is probably better from a design stand point of view, would be to pass in a delegate to the view controller contained in the pop over. More here. This way, the view controller displayed can send data back to your main view controller.