Call method in different controller in objective c - objective-c

Question

I have a view controller from where I will be showing a window controller using [runmodal]. I have some textfields and button in the modal window. When i click the button i need to call a method in view controller with the collective data from window controller. How can i achieve this? Is there anything to do with custom delegate method? As I am new to Mac dev and objective c some one help me to do.

Answer 1

You can use the delegation pattern. You define a protocol like this:
#protocol DataProviderDelegate <NSObject>
- (NSDictionary *) retrieveData;
#end
implement this protocol in your view controller:
#interface MainViewController () <DataProviderDelegate>
#end
#implementation MainViewController {
...
- (NSDictionary *) retrieveData {
....
}
...
#end
In your window controller you define a delegate property
#interface ModalWindowController : NSWindowController
#property (nonatomic, weak) id <DataProviderDelegate> dataProviderDelegate;
#end
From the main view controller, set that property to self
modalWindow.dataProviderDelegate = self
At this point the modal window controller is able to call any method of the view controller that is defined in the DataProviderDelegate protocol - for instance:
if (self.dataProviderDelegate) {
[self.dataProviderDelegate retrieveData];
}
To dig more in the delegation pattern I suggest to google for it

Answer 2

You can use a delegate for this. In the ModalViewController you will have to implement a delegate that will have a method per action (textfields, buttons) :
ModalViewController.h
#class ModalViewController;
#protocol ModalViewControllerDelegate <NSObject>
- (void)modalViewControllerDelegateButtonPressed:(APPCameraOverlay *)overlay;
- (void)modalViewControllerDelegate:(APPCameraOverlay *)overlay
textFieldEdited:(NSString *)text;
#end
#interface ModalViewController : UIViewController
#property (nonatomic, weak) id <ModalViewControllerDelegate> delegate;
#end
Then, you will be able to call your delegate methods inside your ModalViewController.m :
ModalViewController.m
// The method linked to your button
- (IBAction)actionButtonPressed {
[self.delegate modalViewControllerDelegateButtonPressed:self];
}
// Your textfield method that is called when input has changed
- (void)textFieldDidEndEditing:(UITextField *)textField {
[self.delegate modalViewControllerDelegate:self
textFieldEdited:textField.text];
}
Now, you just have to set your ModalViewController delegate object in the ViewController when showing the modal controller :
ViewController.m
#import "ModalViewController.h"
// We create an extension to the class to implement the delegate protocol
#interface ViewController () <ModalViewControllerDelegate>
#end
#implementation ViewController
// This method gets called by apple when a view controller is showed (modally, pushed or embedded)
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
// if the view that is showed is the ModalViewController
if ([segue.destinationViewController isKindOfClass:[ModalViewController class]]) {
ModalViewController *controller = segue.destinationViewController;
controller.delegate = self;
}
}
// You have to implement the delegate methods now :
- (void)modalViewControllerDelegateButtonPressed:(APPCameraOverlay *)overlay {
// Do whatever you want when the button is pressed on the ModalViewController
}
- (void)modalViewControllerDelegate:(APPCameraOverlay *)overlay
textFieldEdited:(NSString *)text {
// Do whatever you want when the textfield is edited
}
#end

Answer 3

Add the view controller as an instance variable to your (subclassed) window controller, and then when the button is clicked you can send a method to the view controller with the collective data from the window controller.