Having two view controller within a navigation controller:
PhoneNumbersTVC > holds a list of phone numbers added by NewPhoneNumberTVC
NewPhoneNumberTVC > a controller for adding phone numbers
When I tap on cancel on NewPhoneNumberTVC I like to get back to PhoneNumbersTVC with a delegation as follow.
PhoneNumbersTVC.h
#import <UIKit/UIKit.h>
#import "NewPhoneNumberTVC.h"
#interface PhoneNumbersTVC : UITableViewController <NewPhoneNumberTVCDelegate>
#end
PhoneNumbersTVC.m
- (void)saveBtnWasTappedOnNewPhoneNumberTVC:(NewPhoneNumberTVC *)newPhoneNumberTVC
{
NSLog(#"saveBtnWasTappedOnNewPhoneNumberTVC");
[newPhoneNumberTVC.navigationController popViewControllerAnimated:YES];
}
- (void)cancelBtnWasTappedOnNewPhoneNumberTVC:(NewPhoneNumberTVC *)newPhoneNumberTVC
{
NSLog(#"cancelBtnWasTappedOnNewPhoneNumberTVC");
[newPhoneNumberTVC.navigationController popViewControllerAnimated:YES];
}
NewPhoneNumberTVC.h
#import <UIKit/UIKit.h>
#class NewPhoneNumberTVC;
#protocol NewPhoneNumberTVCDelegate <NSObject>
- (void)saveBtnWasTappedOnNewPhoneNumberTVC:(NewPhoneNumberTVC *)newPhoneNumberTVC;
- (void)cancelBtnWasTappedOnNewPhoneNumberTVC:(NewPhoneNumberTVC *)newPhoneNumberTVC;
#end
#interface NewPhoneNumberTVC : UITableViewController
#property (weak, nonatomic) id <NewPhoneNumberTVCDelegate> delegate;
#property (strong, nonatomic) NSManagedObjectContext *managedOC;
#property (weak, nonatomic) IBOutlet UITextField *phoneNumberTextField;
- (IBAction)saveBtnTapped:(UIBarButtonItem *)sender;
- (IBAction)cancelBtnTapped:(UIBarButtonItem *)sender;
#end
NewPhoneNumberTVC.m
- (IBAction)cancelBtnTapped:(UIBarButtonItem *)sender
{
NSLog(#"cancelBtnTapped");
self.phoneNumberTextField.text = #"";
self.phoneKindTextField.text = #"";
[self.delegate cancelBtnWasTappedOnNewPhoneNumberTVC:self];
}
When I tap on cancel on NewPhoneNumberTVC I see that above method cancelBtnTapped fires but delegation does not work, no method executes in PhoneNumbersTVC. View doesn't go away and I don't see: cancelBtnWasTappedOnNewPhoneNumberTVC on console.
If you want this method cancelBtnWasTappedOnNewPhoneNumberTVC: get called, you definitely need to set the delegate of your NewPhoneNumberTVC object to a PhoneNumbersTVC object. For example, there should be existing some codes in PhoneNumbersTVC.m :
NewPhoneNumberTVC *myNewPhoneNumberTVC = [[NewPhoneNumberTVC alloc] init];
myNewPhoneNumberTVC.delegate = self;
You can log as following to verify that the delegate is set successfully or not"
NewPhoneNumberTVC.m
- (IBAction)cancelBtnTapped:(UIBarButtonItem *)sender
{
NSLog(#"cancelBtnTapped");
self.phoneNumberTextField.text = #"";
self.phoneKindTextField.text = #"";
NSLog(#"self.delegate :%#",self.delegate);
[self.delegate cancelBtnWasTappedOnNewPhoneNumberTVC:self];
}
Related
I have a UIViewController on a UINavigationStack and from this UIView I load another view not onto the stack but as a subview. This view that I load is just a preferences view for the app that I overlay onto what ever is showing.
i.e.
myViewController <- on the stack button touch loads as a subview to myViewController
+ prefrencesViewController
My question is, is there a way to call a method thats in myViewController from prefrencesViewController? I am trying to use delegates and protocols but its not working, so I am hoping there is either an easy way to do this I don't know about yet or maybe I could get some help with my delegate/protocol...
This is what my code looks like for delegate and protocol set up
//prefrencesViewController.h
#protocol GetPrefrencesViewControllerDelegate <NSObject>
-(void)reloadViewFromSavedPrefrences;
#end
//delegates and protocols
#property (nonatomic, weak) id <GetPrefrencesViewControllerDelegate> delegate;
//prefrencesViewController.m
//delegates and protocols
#synthesize delegate;
//.. inside button action
[[self delegate] reloadViewFromSavedPrefrences];
//myViewController.h
#import "prefrencesViewController.h"
#interface myViewController : UIViewController <UITabBarDelegate, GetGUIEncodedData, GetPrefrencesViewControllerDelegate> {
// prefrencesViewController set up
prefrencesViewController *pvc;
#property (strong, nonatomic) prefrencesViewController *pvc;
//myViewontroller.h
#synthesize pvc;
- (void)viewDidLoad
{
//..
[pvc setDelegate:self];
}
//Delegate and prefrences.. Saved pressed reload the view here.
-(void)reloadViewFromSavedPrefrences {
NSLog(#"WORKED");
}
any help would be greatly appreciated
I'm not sure that you are following the steps that I will present below but if you don't here is the example.
PresentedViewController.h
//import stuff
#protocol PresentedViewControllerDelegate <NSObject>
-(void)methodThatSouldBeImplementedByOtherController; //you can add params
#end
#interface PresentedViewController : UIViewController {
//instance variables
}
#property (nonatomic, assign(week for ARK)) id<PresentedViewControllerDelegate>delegate
//public methods here
PresentedViewController.m
#implementation PresentedViewController
#synthesize delegate;
//method implementation here
-(IBAction)buttonThatWillCallTheDelegate:(id)sender {
if([self.delegate respondsToSelector:#selector(methodThatSouldBeImplementedByOtherController)]) {
[self.delegate methodThatSouldBeImplementedByOtherController];
}
}
ControllerThatWillPresent.h
#interface ControllerThatWillPresent : UIViewController <PresentedViewControllerDelegate> {
//instance variables
}
//some methods maybe
ControllerThatWillPresen.m
#implementation ControllerThatWillPresen
-(void)methodThatWillShowTheVC {
PresentedViewController *vc = [PresentedViewController alloc] init]; //initWithNibname...
vc.delegate = self;
//presentVc, pushVc, addChild ...
}
-(void)methodThatSouldBeImplementedByOtherController {
//do stuff in delegate method
}
I'm trying to pass an integer between two views. When I return from View1 to MainView, the value is not passed and the NSLog(#"Changed map") is not showing in the console. I looked for the answer and tried everything, but it just won't work! Feels like somethings wrong with the delegate...
Any ideas?
View1.h
#class FlipsideViewController;
#protocol FlipsideViewControllerDelegate
- (void)flipsideViewControllerDidFinish:(FlipsideViewController *)controller;
-(void)flipsideViewControllerSelectionChangedToIndex:(int)index;
#end
#interface FlipsideViewController : UIViewController {
}
#property (weak, nonatomic) id <FlipsideViewControllerDelegate> delegate;
#property (nonatomic, retain) IBOutlet UISegmentedControl *mapType;
- (IBAction)valueChangedMap:(id)sender;
#end
View1.m
-(IBAction)valueChangedMap:(id)sender {
[self.delegate flipsideViewControllerSelectionChangedToIndex:[sender selectedSegmentIndex]];
NSLog (#"%d",[sender selectedSegmentIndex]);
[self dismissViewControllerAnimated:YES completion:nil];
}
MainView.h
#interface MainViewController : UIViewController <FlipsideViewControllerDelegate, UIPopoverControllerDelegate, MKMapViewDelegate> {}
#property (weak, nonatomic) IBOutlet MKMapView *mapView;
#property(weak) id<FlipsideViewControllerDelegate> delegate;
#end
MainView.m
-(void)flipsideViewControllerSelectionChangedToIndex:(int)index {
NSLog(#"Changed map");
if (index == 0) mapView.mapType = MKMapTypeStandard;
if (index == 1) mapView.mapType = MKMapTypeHybrid;
if (index == 2) mapView.mapType = MKMapTypeSatellite;
}
You only need an actual delegate property on your view1, and your mainView simply needs to respond to that delegate protocol. Here is what your delegate protocol should look like:
#property(nonatomic,unsafe_unretained) id delegate;
Now in your code when, mainview presents or pushes view1 you need to wire up the delegate like this (pseudo code):
view1.delegate = self;
Also a few nitpicks... you should never have a viewcontroller dismissing itself, mainView should dismiss the view1 when that 'finished' delegate method fires. In addition you should always check that a delegate responds to a selector before firing:
if([self.delegate respondsToSelector:#selector(yourselectorname)]) {
[self.delegate yourselectorname];
}
I'm working through the IOS HelloWorld example and I have a question regarding setting the delegate for a TextField. In the example it was as easy as control-dragging from the TextField to the ViewController. But now say I wanted to create a custom class to act as my delegate as so:
#import <Foundation/Foundation.h>
#interface SweetAssDelegate : NSObject <UITextFieldDelegate>
- (BOOL)textFieldShouldReturn:(UITextField *)theTextField;
#end
#import "SweetAssDelegate.h"
#implementation SweetAssDelegate
- (BOOL)textFieldShouldReturn:(UITextField *)theTextField
{
NSLog(#"Calling Delegate");
[theTextField resignFirstResponder];
return YES;
}
#end
How can I set this class to be the delegate of the TextField? As far as I can tell there is not way to accomplish this through the GUI. I tried manually setting the delegation after window load with no success:
#import "ViewController.h"
#import "SweetAssDelegate.h"
#interface ViewController ()
#property (weak, nonatomic) IBOutlet UITextField *inputField;
#end
- (void)viewDidLoad
{
[super viewDidLoad];
SweetAssDelegate *foo = [[SweetAssDelegate alloc] init];
[self.inputField setDelegate:foo];
NSLog(#"Delegate: %#", self.inputField.delegate);
}
I actually receive some sort of memory exception when bringing up the keyboard? Any ideas? Thanks.
As a side question, where should I always use viewDidLoad to initialize any variables? I noticed that init was not being called???
Your delegate object, foo, is allowed to fall out of scope and is released at the end of viewDidLoad and by the time the keyboard comes up, it doesn't exist anymore. Make it an ivar (or property) of your view controller, or otherwise make sure that foo doesn't fall out of scope at the end of viewDidLoad.
Thus, it could be something like:
#interface ViewController ()
#property (weak, nonatomic) IBOutlet UITextField *inputField;
#property (strong, nonatomic) SweetAssDelegate *foo;
#end
- (void)viewDidLoad
{
[super viewDidLoad];
self.foo = [[SweetAssDelegate alloc] init];
[self.inputField setDelegate:self.foo];
NSLog(#"Delegate: %#", self.inputField.delegate);
}
Your textfield delegate must have the implemented to be your textfield delegate I guess.
A delegate manages the communication between objects, which means your custom delegate must allow communication between objects and must provide methods, the textfield can work with...
Another example is a tableView:
You can make a custom delegate which implements the delegates and then calls some tableview related Methods...
Here this code might be interesting for you:
#interface myCustomDelegateForTextFields <UITextFieldDelegate>
#end
#implementation myCustomDelegateForTextFields
- (BOOL)textFieldShouldReturn:(UITextField *)theTextField {
return TRUE;
}
#end
#implementation ViewController
myCustomDelegateForTextFields *txtfielddelegate = [[myCustomDelegateForTextFields alloc] init];
UITextField *whatever;
whatever.delegate = txtfielddelegate;
//your textfield now listens to the BOOL method in your custom delegate
#end
Is it that what u were looking for? :)
you can ofc pack the myCustomDelegateForTextField delegate in another class and call the class
I'm trying to assign SecondViewController as a delegate object of FirstViewController (if I understand correctly). However FirstViewController doesn't send any messages to SecondViewController.
Am I allowed to pretend as though SecondViewController did get a message from FirstViewController and respond to the FirstViewController? (Note: My SecondViewController is in charge of a view that has a button. When I press the button on my SecondViewController's view I want it to tell the FirstViewController to update its view)
FirstViewController.h
#import <UIKit/UIKit.h>
#protocol FirstViewControllerDelegate <NSObject>
#optional
- (void) setAnotherLabel;
#end
#interface FirstViewController : UIViewController {
IBOutlet UILabel *label;
id <FirstViewControllerDelegate> delegate;
}
#property (nonatomic, retain) IBOutlet UILabel *label;
#property (nonatomic, assign) id <FirstViewControllerDelegate> delegate;
- (void) pretendLabel;
- (void) realLabel;
#end
FirstViewController.m
#import "FirstViewController.h"
#implementation FirstViewController
#synthesize label;
#synthesize delegate;
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void) setAnotherLabel;
{
label.text =#"Real";
[self.view setNeedsDisplay];
}
- (void) pretendLabel;
{
label.text =#"Pretend";
[self.view setNeedsDisplay];
}
- (void) realLabel;
{
[self setAnotherLabel];
}
- (void)viewDidLoad
{
[super viewDidLoad];
label.text=#"Load";
[self pretendLabel];
}
...
#end
SecondViewController.h
#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#import "FirstViewController.h"
#interface SecondViewController : UIViewController <UIImagePickerControllerDelegate, UINavigationControllerDelegate, FirstViewControllerDelegate>
{
UIImage *image;
IBOutlet UIImageView *imageView;
}
- (IBAction) sendPressed:(UIButton *)sender;
- (IBAction) cancelPressed:(UIButton *)sender;
#end
SecondViewController.m
#import "SecondViewController.h"
#implementation SecondViewController
- (IBAction) sendPressed:(UIButton *)sender
{
FirstViewController *fvc = [[FirstViewController alloc] init];
[fvc setDelegate:self];
//how do I find out if I'm actually the delegate for FirstViewController at this point?
[fvc realLabel];
self.tabBarController.selectedIndex = 0;//switch over to the first view to see if it worked
}
There are a few issues with this and what appears to be a bit of confusion.
I assume that FirstViewController and SecondViewController are in separate tabs in the tab bar controller.
In the sendPressed: method, you're creating a new instance of FirstViewController - this is not the same FirstViewController that is in your tab bar controller and why calling realLabel has no effect.
The second point is that you appear to misunderstand how delegation works - there is no reason for a delegate in the code you posted.
Good read for getting to grips with delegates: http://developer.apple.com/library/ios/#documentation/Cocoa/Conceptual/CocoaFundamentals/CommunicatingWithObjects/CommunicateWithObjects.html
As for a solution to your problem there are a few options:
Post a notification from SecondViewController that FirstViewController is observing (lots of information available on the net regarding notifications).
Get the specific instance of FirstViewController within the self.tabBarController.viewControllers array and call the method from there. Something like...
- (IBAction) sendPressed:(UIButton *)sender
{
for(UIViewController *controller in self.tabBarController.viewControllers)
{
if([controller isKindOfClass:[FirstViewController class]])
{
FirstViewController *firstViewController = (FirstViewController *)controller;
[firstViewController realLabel];
}
}
self.tabBarController.selectedIndex = 0;//switch over to the first view to see if it worked
}
There are more options available than this, but the above will give you a good start into researching the best approach for your need.
Hope this helps.
I have a simple project to present a modal view controller and transfer back a string based on which button in the modal VC that gets pressed. I based it all on watching the Stanford class on iTunes U. It looks like I have everything correct, but I get a couple of compiler warnings.
First I get one called passing argument 1 of 'setDelegate:' from incompatible pointer type in TransferViewController.m
Second I get four warnings called Invalid receiver type 'id <MyModalViewControllerDelegate>*' but these aren't displayed in the build results area, rather next to the offending lines in MyModalViewController.m, both lines in each of the button actions.
Here's the code...
// TransferViewController.h
#import <UIKit/UIKit.h>
#import "MyModalViewController.h";
#interface TransferViewController : UIViewController <MyModalViewControllerDelegate> {
UILabel *label;
UIButton *button;
}
#property (nonatomic, retain) IBOutlet UILabel *label;
#property (nonatomic, retain) UIButton *button;
- (IBAction)updateText;
#end
// TransferViewController.m
#import "TransferViewController.h"
#implementation TransferViewController
#synthesize label;
#synthesize button;
- (IBAction)updateText {
MyModalViewController *myModalViewController = [[MyModalViewController alloc] init];
myModalViewController.delegate = self; // I get the warning here.
[self presentModalViewController:myModalViewController animated:YES];
[myModalViewController release];
}
- (void)myModalViewController:(MyModalViewController *)controller didFinishSelecting:(NSString *)selectedDog {
label.text = selectedDog;
[self dismissModalViewControllerAnimated:YES];
}
#end
// MyModalViewController.h
#import <UIKit/UIKit.h>
#protocol MyModalViewControllerDelegate;
#interface MyModalViewController : UIViewController {
UIButton *abby;
UIButton *zion;
id <MyModalViewControllerDelegate> delegate;
}
#property (assign) id <MyModalViewControllerDelegate> delegate;
- (IBAction)selectedAbby;
- (IBAction)selectedZion;
#end
#protocol MyModalViewControllerDelegate <NSObject>
#optional
- (void)myModalViewController:(MyModalViewController *)controller didFinishSelecting:(NSString *)selectedDog;
#end
// MyModalViewController.m
#import "MyModalViewController.h"
#implementation MyModalViewController
#synthesize delegate;
- (IBAction)selectedAbby {
if ([self.delegate respondsToSelector:#selector (myModalViewController:didFinishSelecting:)]) {
[self.delegate myModalViewController:self didFinishSelecting:#"Abby"];
}
}
- (IBAction)selectedZion {
if ([self.delegate respondsToSelector:#selector (myModalViewController:didFinishSelecting:)]) {
[self.delegate myModalViewController:self didFinishSelecting:#"Zion"];
}
}
Get rid of those *s after id <something> and before delegate.
So make this
id <MyModalViewControllerDelegate> *delegate;
this
id <MyModalViewControllerDelegate> delegate;