I have two view controllers. We'll call them listViewController and mapViewController. The listViewController shows first, a user taps a button that shows the mapViewController. The user taps a button on a annotation which is where my problems start.
When the user taps a button on mapViewController, I would like to call a method listViewController and dismiss mapViewController. To do this I am using this code:
mapViewController.m
listViewController* lvc = [[listViewController alloc] initWithNibName:nil bundle:nil];
[lvc getInformation:StringParameter];
[self dismissViewControllerAnimated:YES completion:nil];
However, when executing getInformation it seems that the listViewController class has been dealloc'd because all of the objects that I initialized in the viewDidLoad on listViewController are now nil including self, which just breaks everything.
I assume I'm creating the listViewController object incorrectly in mapViewController. I've tried it with a nil for nibName with the same result.
Ok, Let me clear one thing. On listViewController, you presentViewController a mapViewcontroller right? And you want invoke getInformation of the instance from mapViewController. In the code you're added, you instantiate listViewController again. You have 2 different instance of listViewController.
One option is to use a delegate pattern:
In your MapViewController.h file:
#protocol MapViewControllerDelegate <NSObject>
-(void)dismissMe;
-(void)getInformation:(NSString *)stringParameter;
#end
#interface MapViewController : UIViewController
#property (weak)id <MapViewControllerDelegate> delegate;
#end
In your MapViewController.m file:
-(void)annotationButtonTap:(id)button
{
[self.delegate getInformation:stringParameter];
[self.delegate dismissMe];
}
In your ListViewController.h
#import "MapViewController.h"
#interface ListViewController : UIViewController <MapViewControllerDelegate>
-(void)dismissMe
{
[self dismissViewControllerAnimated:YES completion:nil];
}
-(void)getInformation:(NSString *)stringParameter
{
//do whatever you plan with stringParameter
}
And somewhere in you ListViewController.m file where you create the MapViewController instance:
mapViewController = [[MapViewController alloc] initWithNibName:#"MapViewController" bundle:nil];
mapViewController.delegate = self; //make sure you do this
Related
I am trying to send string from Second VC to First VC. I have assigned delegate to first VC and given protocol in second VC but I don't see the method in First VC is being called when Second VC sends some data.
Code
First VC
FirstViewController.h
#import <UIKit/UIKit.h>
#import "SecondViewController.h"
#interface FirstViewController : UIViewController <cellDelegate>
#end
FirstViewController.m
- (void)printString:(NSString *)string{
NSLog(#"Received string: %#",string);
}
SecondViewController.h
#protocol cellDelegate <NSObject>
- (void)printString:(NSString *)string{
#end
#interface SecondViewController : UIViewController
#property (nonatomic, weak) id <cellDelegate> delegate;
#end
SecondViewController.m
- (IBAction)buttonPressed:(id)sender {
if ([self.delegate respondsToSelector:#selector(printString:)]) {
[self.delegate printString:#"arrow"]];
}
}
Any help is greatly appreciated.
You forgot to do
SecondViewcontroller *vc;
vc.delegate=self;
On first view controller
Maybe you just forgot to assign your secondViewController.delegate to self.
1- In first viewController, before pushing secondViewController, with that SecondViewController instance do:
secondViewController.delegate = self;
I can not comment, so if this does not work out just let me know or share more code.
When you navigate from one VC to Second VC you can set the delegate.
SecondViewcontroller *secondVC = [self.storyboard instantiateViewControllerWithIdentifier:#"SecondViewcontroller"];
secondVC.delegate = self;
[self.navigationController pushViewController:secondVC animated:YES];
This code writes on FirstViewController. Hope it helps you.
I have a Controller A and there is a UIButton, which on click I am presenting a new Controller B. But the problem is that the controller B is first embedded with a NAV. So ultimately I am presenting the UINavigationController.
Now there is a UIButton in Controller B on which the controller will dismiss and a delegate should be passed on controller A with some message
Controller A UIButtonCode
- (IBAction)summaryButtonClick:(id)sender {
UIStoryboard* storyBoard=[UIStoryboard storyboardWithName:#"Main" bundle:nil];
UINavigationController* summaryVC=[storyBoard instantiateViewControllerWithIdentifier:#"SummaryNavVC"];
[self presentViewController:summaryVC animated:YES completion:nil];
summaryVC=nil;
}
Now Controller B
.h file
#import <UIKit/UIKit.h>
#protocol SummaryViewWhatsNewDelegate <NSObject>
#required
- (void) SummaryViewWhatsNew:(NSString*)title;
#end
#interface SummaryViewController :
UIViewController<UITableViewDataSource,UITableViewDelegate>
{
id <SummaryViewWhatsNewDelegate> _delegate;
}
#property (nonatomic,strong) id delegate;
#property (weak, nonatomic) IBOutlet UITableView *summaryTableView;
- (IBAction)closeSummaryView:(id)sender;
#end
.m
//Button Click
[self dismissViewControllerAnimated:YES completion:^{
[_delegate SummaryViewWhatsNew:#"Sales Triggers Filter"];
}];
I have already made the implementation of delegate in my Controller A
.h
#interface ControllerA : UIViewController<SummaryViewWhatsNewDelegate>
.m of Controller A
#pragma mark -ControllerB Delegate
-(void)SummaryViewWhatsNew:(NSString *)title{
NSLog(#"Delegate Called");
}
In this case I know I haven't provided the delegate.self part as I am presenting the NAV controller and not the Controller B
So I made a Object in viewDidLoad and Controller *B and set the delegate to self. But it doesn't work and delegate is never called
On the other hand if I only present the Cntroller B without Navigation and just before presenting I keep the b.delegate=self, it works.
Another alternate can be firing Notifications. But I want to work with delegates.
So is there any way to call the delegate of the presented view controller which is embedded by Nav. Any help will be highly appreciated.
Well I got the answer
We have to fetch the Controller object from NAV
Where I a presenting I just need to add these lines and it worked
UIStoryboard* storyBoard=[UIStoryboard storyboardWithName:#"Main" bundle:nil];
UINavigationController* summaryVC=[storyBoard instantiateViewControllerWithIdentifier:#"SummaryNavVC"];
//Add These lines in order to get the object of Controller B.
// SummaryViewController is my Controller B
SummaryViewController* summary=[[summaryVC viewControllers] objectAtIndex:0];
summary.delegate=self;
[self presentViewController:summaryVC animated:YES completion:nil];
And it worked.
What I did:
I am using scrollview to view some UIView(s), with paging enabled.
In last page in subview of scrollView I added a button.
I also wrote a function which is in subclass of UIView ,which is invoked when we press that button.
I want to view storyboard when I press that button.
You need to implement protocol method for custom UIView class.
For example;
#import <UIKit/UIKit.h>
#protocol YourCustomViewDelegate <NSObject>
- (void)buttonTapped;
#end
#interface YourCustomView : UIView
#property (nonatomic, strong) id< YourCustomViewDelegate > delegate;
#end
And the .m file you can call buttonTapped delegate method.
- (void)myCustomClassButtonTapped:(id)sender
{
[self.delegate buttonTapped];
}
For proper work;
set your custom view delegate to self in your custom view controller.
add buttonTapped method to that view controller
And do what you want in that method. Present/Push view controllers like the other answers explained.
Edit
I will try to illustrate very simple usage of protocols, hope it will help you.
#import "MyViewController.h"
#import "YourCustomView.h"
#interface MyViewController ()<YourCustomViewDelegate> // this part is important
#end
#implementation MyViewController
- (void)viewDidLoad {
[super viewDidLoad];
YourCustomView *customView = // initialize your custom view, I suppose that you already did it
customView.delegate = self;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void)buttonTapped
{
YOUR_VIEW_CONTROLLER_CLASS *viewCon =[storyboard instantiateViewControllerWithIdentifier:#"mainVC"]; //mainVC is just a example and u will have to replace it with your viewController storyboard id
//Pushing VC
[self.navigationController pushViewController:viewCon animated:YES];
}
Take a look at this
YourViewController *obj=[[YourViewController alloc]init];
UINavigationController *nav=[[UINavigationController alloc]initWithRootViewController:obj];
[[[UIApplication sharedApplication]keyWindow].rootViewController presentViewController:nav animated:YES completion:NULL];
try like this
UIStoryboard* storyboard = [UIStoryboard storyboardWithName:#"MainStoryboard" bundle:nil];
UIViewController* initialView = [storyboard instantiateInitialViewController];
Firstly you need to set a storyboard Id to your ViewController, namely "mainVC". Then you could pus/present it using below code :-
YOUR_VIEW_CONTROLLER_CLASS *viewCon =[storyboard instantiateViewControllerWithIdentifier:#"mainVC"]; //mainVC is just a example and u will have to replace it with your viewController storyboard id
//Pushing VC
[self.navigationController pushViewController:viewCon animated:YES];
//OR presenting VC
[self presentViewController:viewCon animated:YES completion:nil];
Also in case if you want your another storyboard to be initiated then below,
UIStoryboard* storyboard = [UIStoryboard storyboardWithName:#"MainStoryboard" bundle:nil]; //Change MainStoryboard with your storyboard id
hope this will help
the way i perceive your question is
->Rightnow your inside you are in UIView class and inside it there is a button by clicking it you want to push or present a ViewController and offcourse from inside your UIView class you cant push or present your view Controller. So
you can do one simple thing first inside action method make a ref(forward declaration) or you can make a whole new object of your ViewController class in which your UIView is present right now , then call a function(which exist in your ViewController) like
//function inside your uiview calss
- (void)btnaction
{
[_objCSInformationViewController pushViewController];
}
// function inside your view controller
-(void)pushViewController
{
yourViewController *objViewController = [[yourViewController alloc]initWithNibName:#"yourViewController" bundle:nil];
[strong.navigationController pushViewController:objViewController animated:YES];
}
I have a HomeViewController which has a tableView populated with the array tableViewArray (originally empty). When I tap on a barButton, I segue modally to another View Controller called OutsideViewController which has another tableView populated by a different array.
What I would like to do is the following:
When I tap on a row in my OutsideViewController, I would like to add the selected string value to the tableViewArray so that when I go back to HomeViewController, the tableView has that new item listed in the tableView.
So far, this is what I have tried:
In the -didSelectRowAtIndexPath method of my OutsideViewController.m I have this piece of code:
NSString *selectedRow = [outsideArray objectAtIndex:indexPath.row];
NSMutableArray *temporaryArray = [NSMutableArray arrayWithObject:selectedRow];
HomeViewController *homeVC = [[HomeViewController alloc] init];
homeVC.tableViewArray = temporaryArray;
That code works but the tableView in HomeViewController is still empty when I return. Do I have to reload the tableView data?
Am I doing this right?
This is how I have set up my View Controllers in Storyboard:
HomeViewController -(modal segue)-> Navigation Controller --> OutsideViewController
Also, the return from OutsideViewController to HomeViewController is done by this line of code:
[self dismissViewControllerAnimated:YES completion:^{ }];
What you're doing wrong is you're allocationg a new HomeViewController. What I would do is keeep a reference to your HomeViewController in your OutsideViewController. Here is how.
First, in OutsideViewController.h, create a property, like this :
#property (nonatomic, weak) HomeViewController *homeVC;
Don't forget to add #class HomeViewController; in your .h, and #import "HomeViewController.h" in your .m
In HomeViewController, implement the prepareForSegue: method like this (replace ModalSegueIdentifier with your segue's identifier) :
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
if ([segue.identifier isEqualToString:#"ModalSegueIdentifier"]) {
OutsideViewController *modalVC = (OutsideViewController*)segue.destinationViewController;
modalVC.homeVC = self;
}
}
Then, in OutsideViewController.m, instead of doing :
HomeViewController *homeVC = [[HomeViewController alloc] init];
homeVC.tableViewArray = temporaryArray;
Do this :
_homeVC.tableViewArray = temporaryArray;
When you leave your modal VC, your HomeVC will have the correct array. Don't forget to refresh your UITableView !
NB: Of course, there are many other ways, and it's maybe not the best one. But still, it should work.
You can achieve this too using delegation. You have to create a protocol in your OutsideViewController with a method that is responsible for sending the new object to your HomeViewController. Do this in OutsideViewController.h:
#protocol OutsideViewDelegate <NSObject>
- (void)OutsideViewController:(OutsideViewController *)controller didAddObject:(NSString *)object;
#end
In the implementation file you have to change a little bit the didSelectRowAtIndexPath: method:
NSString *selectedRow = [outsideArray objectAtIndex:indexPath.row];
[self.delegate OutsideViewController:self didAddObject:selectedRow];
In your HomeViewController.h you have to make your class conforms to the protocol:
#interface HomeViewController : UIViewController <OutsideViewDelegate>
After, create a property for the delegate:
#property (nonatomic, weak) id <OutsideViewDelegate> delegate;
To finish the process, implement the protocol in your HomeViewController.m to receive the new object from the OutsideViewController:
- (void)OutsideViewController:(OutsideViewController *)controller didAddObject:(NSString *)object
{
if (object != nil)
{
[self.tableViewArray addObject:object];
}
[self dismissViewControllerAnimated:YES completion:nil];
}
The code above depends of if your tableViewArray object is mutable or not. If it's not, you can change the type of the object argument in the protocol method to an inmutable array object and just assign tableViewArray to the new array.
EDIT:
In the prepareForSegue: method don't forget to set the delegate:
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([[segue identifier] isEqualToString:#"SEGUE_IDENTIFIER"]) {
OutsideViewController *outsideVC = (OutsideViewController *)[segue destinationViewController];
[outsideVC setDelegate:self];
}
}
First of all make sure you alloc, init your tableViewArray in HomeViewController
Second , In this line
HomeViewController *homeVC = [[HomeViewController alloc] init]
you are creating a new reference to your HomeViewController which is not correct, you need to pass correct reference, possibly creating HomeViewController variable in your OutsideViewController
Even though you correctly do first and second suggestion you will still see an empty tableview because you dont reload the tableview, somehow you need to fire [self.tableview reloadData]; method.
That means; you need to learn Delegate or NSNotifications pattern to communicate between child->parent scenarios
How do I set up a simple delegate to communicate between two view controllers?
http://mobile.tutsplus.com/tutorials/iphone/ios-sdk_nsnotificationcenter/
For your question just create a delegate in your Outside;
in your OutsideViewController.h
#import <UIKit/UIKit.h>
#protocol OutsideDelegate;
#interface{}//bunch of interface stuff
// Declare a property for the delegate
#property (weak) id <OutsideDelegate> delegate;
#end
// Protocol Header
#protocol OutsideDelegate <NSObject>
#optional
- (void)dismissPop:(NSMutableArray *)list;
#end
in your OutsideViewController.m
#synthesize delegate;
//run delegate method
[delegate dismissPop:temporaryArray];
[self dismissViewControllerAnimated:YES completion:^{ }];
in your HomeViewController.h
#import "OutsideViewController.h"
#interface OutsideViewController : UITableViewController<OutsideDelegate>
{}
#property (strong, nonatomic) OutsideViewController *pvc;
in your HomeViewController.m
#synthesize pvc;
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
if ([[segue identifier] isEqualToString:#"your segue"]) {
pvc = [segue destinationViewController];
[pvc setDelegate:self];
}
}
// delegate callback function
- (void)dismissPop:(NSMutableArray *)list {
self.tableViewArray=list;
[self.tableView reloadData];
}
Another Solution Would be
Change your view stack to this:
Navigation Controller --> HomeViewController -(push segue)--> OutsideViewController
and apply rdurand's answer
and add this to your HomeViewController :
-(void)viewDidAppear:(BOOL)animated
{
[self.tableview reloadData];
}
In this solution since you are just push-pop viewcontrollers in a nabigation stack viewDidAppear will be called in HomeViewController everytime when you pop OutsideViewController.
In a view, let's call it firstView I created a secondView as follows and pushed it if certain thing happened in the firstView:
SecondViewController *secondVC = [[secondViewController alloc] initWithNibName:#"SecondViewController" bundle:nil];
[self.navigationController pushViewController:secondVC animated:YES];
[secondVC release];
Now when I'm in the secondView if let say a button is pressed I want to go back to firstView and also pass back a value from secondView to the firstView (let say an integer value of a textfield from secondView to the firstView).
Here is what I tried:
#protocol SecondViewControllerDelegate;
#import <UIKit/UIKit.h>
#import "firstViewController.h"
#interface SecondViewController : UIViewController <UITextFieldDelegate>
{
UITextField *xInput;
id <SecondViewControllerDelegate> delegate;
}
- (IBAction)useXPressed:(UIButton *)sender;
#property (assign) id <SecondViewControllerDelegate> delegate;
#property (retain) IBOutlet UITextField *xInput;
#end
#protocol SecondViewControllerDelegate
- (void)secondViewController:(SecondViewController *)sender xValue:(int)value;
#end
And in the m file
- (IBAction)useXPressed:(UIButton *)sender
{
[self.delegate secondViewController:self xValue:1234]; // 1234 is just for test
}
And then in the firstView I did:
#import "SecondViewController.h"
#interface FirstViewController : UITableViewController <SecondViewControllerDelegate> {
}
#end
And implemented:
- (void) secondViewController:(SecondViewController *)sender xValue:(int)value
{
[self.navigationController popViewControllerAnimated:YES];
}
Now, the problem is for one in FirstViewController I get the warning that "No definition of protocol "SecondViewControllerDelegate" is found, and for two the delegate method (last piece of code above) does not get invoked at all. Can somebody please tell me what's wrong?
After this line
SecondViewController *secondVC = [[secondViewController alloc] initWithNibName:#"SecondViewController" bundle:nil];
Add
secondVC.delegate = self;
Also instead of
- (void) secondViewController:(SecondViewController *)sender xValue:(int)value
{
[self.navigationController popViewControllerAnimated:YES];
}
You should use
- (void) secondViewController:(SecondViewController *)sender xValue:(int)value
{
[sender popViewControllerAnimated:YES];
}
In FirstViewController .h file :
#import "SecondViewController.h"
#interface FirstViewController : UITableViewController <SecondViewControllerDelegate> {
SecondViewController *secondViewController;
}
#end
In implementation file , where you init SecondViewController instance next line assign self to delegate property :
secondViewController.delegate = self;
Next define delegate method :
- (void)secondViewController:(SecondViewController *)sender xValue:(int)value
{
NSLog ("This is a Second View Controller with value %i",value)
}
For problem 1: The #protocol definition for SecondViewControllerDelegate looks like it's in secondViewController.h; are you sure this file is imported in firstViewController.h? Otherwise it won't know about the protocol.
Problem 2: It might be totally unrelated to problem 1. Are you sure the action is hooked up properly? Can you put a NSLog() call in your useXPressed: to make sure that method is actually getting called when you expect it to?