I cannot seem to find this anywhere online. I have an add button in one of my views and I have hooked it up to an IBAction method called add. In my storyboard, I have created a view that has a form all set up on it. I have assigned a class to that view in the storyboard as well. That class is called AddItemViewController.
I am trying to present this view modally and then set the delegate to the view that called the AddItemViewController. However, all I get is an empty UITableViewController that shows up. Here is my code that I'm trying to use:
- (IBAction)add {
AddItemViewController *addItem = [[AddItemViewController alloc] init];
addItem.delegate = self;
[self presentModalViewController:addItem animated:YES];
}
Is there anything I'm missing? Why does it just show an empty table and not the view controller that I set up in the storyboard?
Here is the code from the AddItemViewController:
#interface AddItemViewController : UITableViewController <UITextFieldDelegate> {
}
#property (strong, nonatomic) IBOutlet UITextField *note;
- (void)save:(id)sender;
- (void)cancel:(id)sender;
#end
#implementation AddItemViewController
- (void)viewDidLoad {
}
- (IBAction)cancel:(id)sender {
[self dismissViewControllerAnimated:YES completion:nil];
}
- (IBAction)save:(id)sender {
DbHandler *db = [[DbHandler alloc] init];
[db executeUpdate:self.note];
[self dismissViewControllerAnimated:YES completion:nil];
}
#end
Well, AddItemViewController inherits from UITableViewController, not UIViewController, so it makes sense that a UITableViewController is showing up.
You should initiate the AddItemViewController like this:
AddItemViewController *addItem = [[AddItemViewController alloc] initWithNibName:#"AddItemViewController"];
Related
I have a view with a view controller and when I show this view on screen, I want to be able to pass variables to it from the calling class, so that I can set the values of labels etc.
First, I just tried creating a property for one of the labels, and calling that from the calling class. For example:
SetTeamsViewController *vc = [[SetTeamsViewController alloc] init];
vc.myLabel.text = self.teamCount;
[self presentModalViewController:vc animated:YES];
[vc release];
However, this didn't work. So I tried creating a convenience initializer.
SetTeamsViewController *vc = [[SetTeamsViewController alloc] initWithTeamCount:self.teamCount];
And then in the SetTeamsViewController I had
- (id)initWithTeamCount:(int)teamCount {
self = [super initWithNibName:nil bundle:nil];
if (self) {
// Custom initialization
self.teamCountLabel.text = [NSString stringWithFormat:#"%d",teamCount];
}
return self;
}
However, this didn't work either. It's just loading whatever value I've given the label in the nib file. I've littered the code with NSLog()s and it is passing the correct variable values around, it's just not setting the label.
Any help would be greatly appreciated.
EDIT: I've just tried setting an instance variable in my designated initializer, and then setting the label in viewDidLoad and that works! Is this the best way to do this?
Also, when dismissing this modal view controller, I update the text of a button in the view of the calling ViewController too. However, if I press this button again (to show the modal view again) whilst the other view is animating on screen, the button temporarily has it's original value again (from the nib). Does anyone know why this is?
When a view controller is being initialized, inside the initWithNibName method, the views that reside in the view controller aren't yet initialized and you can't set their properties yet. Do whatever you need that is view based in the "viewDidLoad" method.
I am not a pro but this may help you.
In the header view1.h, declare the desired property:
// view1.h
#interface view1 : UIViewController {
NSString *passingVariable;
}
#property (nonatomic, strong) NSString *passingVariable;
#end
and then in the implementation of view1, synthesize the variable:
// view1.m
#implementation view1
#synthesize passingVariable;
// the rest of the implementation
#end
and, finally in the implementation of the other view controller, view2:
// view2.m
#import "view1.h"
#implementation view2
-(IBAction)changeview
{
view1 *myview = [[view1 alloc] init];
myview.passingVariable = #"Hello Variable";
[self.navigationController pushViewController:myview animated:YES];
}
#end
here i am trying to move from view2 to view 1 and also initializing the passingVariable ivar of view1. hope this will help you.
Here i'm passing the ViewController's label text to SecondViewController's Label Text
ViewController.h
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController
{
// please make your control on XIB set these IBOutlet's
//I'm not showing how to connect these with XIB
IBOutlet UILabel *lblView;
IBOutlet UIButton *buttonGo;
}
//this is method which will push the view
-(IBAction)buttonGoClickAction:(id)sender;
ViewController.m
-(IBAction)buttonGoClickAction:(id)sender
{
SecondViewController *secondViewObject = [[SecondViewController alloc]initWithNibName:#"SecondViewController" bundle:nil];
//before pushing give the text
secondViewObject.string = lblView.text;
[self.navigationController pushViewController:secondViewObject animated:YES];
}
SecondViewController.h
#import <UIKit/UIKit.h>
#interface SecondViewController : UIViewController
{
IBOutlet UILabel *labelView;
NSString *string;
}
//set the string property
#property(nonatomic, retain) NSString *string;
#end
SecondViewController.m
#import "SecondViewController.h"
#implementation SecondViewController
//synthesize string here
#synthesize string;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
//Here you will get the string
labelView.text = string;
}
Firstly you check that have you attach this label IBOutlet in xib or not if you made it via Interface Builder....
use it like this....
SetTeamsViewController *vc = [[SetTeamsViewController alloc] initWithTeamCount:teamCount];
Take a string variable in .h file and set that string here .. NSSting *str in .h
- (id)initWithTeamCount:(int)teamCount {
self = [super init];
if (self) {
// Custom initialization
str = [NSString stringWithFormat:#"%d",teamCount];
}
return self;
}
and set your label in viewDidLoad: or in viewWillApear:
self.teamCountLabel.text = str;
May this will help you
As said by stavash, control in the xib are created in the view did load. To be more precise, they are created with that line :
[super viewDidLoad];
So, mylabel doesn't exist before that time (it is nil).
The easiest way is to do that :
SetTeamsViewController *vc = [[SetTeamsViewController alloc] init];
[self presentModalViewController:vc animated:YES];
vc.myLabel.text = self.teamCount;
[vc release];
The longer but more correct path is to have a member NSString* in SetTeamsViewController class, to set it to teamCount before showing the window, and in the view did load to put that membre value in your label.
Cdt
It depends on your need. You can use Singleton class for sharing of your variables between different classes. Define all variable which you wants share in your DataClass.
in .h file (where RootViewController is my DataClass, replace name with your new class)
+(RootViewController*)sharedFirstViewController;
in .m file
//make the class singleton:-
+(RootViewController*)sharedFirstViewController
{
#synchronized([RootViewController class])
{
if (!_sharedFirstViewController)
[[self alloc] init];
return _sharedFirstViewController;
}
return nil;
}
+(id)alloc
{
#synchronized([RootViewController class])
{
NSAssert(_sharedFirstViewController == nil,
#"Attempted to allocate a second instance of a singleton.");
_sharedFirstViewController = [super alloc];
return _sharedFirstViewController;
}
return nil;
}
-(id)init {
self = [super init];
if (self != nil) {
// initialize stuff here
}
return self;
}
after that you can use your variable in any other class like this
[RootViewController sharedFirstViewController].variable
Hope it's help you:)
With Storyboards the the right way is to pass the indexPath as sender argument in performSegueWithIdentifier
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[self performSegueWithIdentifier:#"segueIdentifier" sender:indexPath];
}
and to set a property in the destination controller:
- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([[segue identifier] isEqualToString: #"segueIdentifier"]) {
NSIndexPath *indexPath = sender;
DetailViewController *dest = [segue destinationViewController];
dest.usersArray = [self.usersArray objectAtIndex:indexPath.row];
}
}
What I have done whenever I needed another class to have the variables from the previous class I either set up a global class that will store the values incase I need them in more locations or in the interface you can set #public variables. These variables can be set using the controller that you created for the next view as such.
controller->pub_var1 = val1;
controller->pub_var2 = val2;
This will be done before you pass the view to the root controller or just before you call the next view. You will need to #import "class.h" so that you can access those public variables.
I can show code if this is not clear
I could use some help with custom delegates. I'm trying to make a protocol that sends a message to its delegate to dismiss the popover view. Here is what I'm trying.
In the popoverViewController.h
#import <UIKit/UIKit.h>
#protocol MyPopoverDelegate <NSObject>
-(void) didSelectLanguage;
#end
#interface Popover : UITableViewController{
id <MyPopoverDelegate> delegate;
NSMutableArray *languageData;
}
#property (nonatomic, assign) id <MyPopoverDelegate> delegate;
#end
.m
#synthesize delegate;
...
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"You selected %#", [languageData objectAtIndex:[indexPath row]]);
[self.delegate didSelectLanguage];
}
...
And in the ViewController that presents the popover
#import <UIKit/UIKit.h>
#import "popoverViewController.h"
#interface ChoicesChoices : UIViewController <UIPopoverControllerDelegate, MyPopoverDelegate>{
UIPopoverController *popover;
}
- (IBAction)facebook:(id)sender;
- (IBAction)twitter:(id)sender;
- (IBAction)sms:(id)sender;
- (IBAction)copy:(id)sender;
- (IBAction)email:(id)sender;
- (IBAction)home:(id)sender;
- (IBAction)mute:(id)sender;
- (IBAction)note:(id)sender;
#property (nonatomic, retain) UIPopoverController* popover;
#end
and .m
#synthesize popover;
...
- (void)didSelectLanguage{
[popover dismissPopoverAnimated:YES];
NSLog(#"didSelectLanguage fired");
}
When I select a row in the table of the popover, didSelectLanguage does not get called. Any ideas on what I might be doing wrong? Thanks for your help.
Make sure you are setting your delegate to the be the view controller that is presenting your popover. Something like this in ChoicesChoices.m:
- (void)presentPopover
{
// assuming ARC for all allocations
Popover *myController = [Popover new];
myController.delegate = self;
self.popover = [[UIPopoverController alloc] initWithContentViewController:myController];
[self.popover presentPopover...]; // two flavors here, FromRect: and FromBarButtonItem:, that's left up to you to choose which one is correct.
}
Make sure you set the delegate in the presenting view controller when you create the instance of your custom class.
popover.delegate = self
Also, it looks like your property is a standard popover controller instead of an instance of your custom view controller.
I have two views in my application: in main view there are input fields that the user must fill and a button connected to the second view. In the second view there is a table view, when the user selects a row automatically returns to the main view.
My problem is that when you return to the main view the values of text fields are cleared.
Any solutions?
Thank you.
Second View header
#class MainViewController;
#interface ListaViewController : UIViewController
<UITableViewDataSource, UITableViewDelegate, UISearchBarDelegate>
{
UITableView *table;
UISearchBar *search;
MainViewController *child;
}
#property (nonatomic, retain) IBOutlet UITableView *table;
#property (nonatomic, retain) IBOutlet UISearchBar *search;
#property (nonatomic, retain) MainViewController *child;
- (IBAction)switchBack:(id)sender;
Second View Implementation:
-(IBAction)switchBack:(id)sender
{
child.selectedCountry = selectedCountry;
child.codiceComune = codiceComune;
[self.navigationController popViewControllerAnimated:YES];
}
First View:
-(void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
cityField.text = selectedCountry;
}
This not work!
-(IBAction)switchBack:(id)sender
{
MainViewController *controller = [[MainViewController alloc] initWithNibName:#"MainViewController" bundle:nil];
controller.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentModalViewController:controller animated: YES];
[controller release];
}
It means you create new MainViewController, not return to previous.
Use this code instead
-(IBAction)switchBack:(id)sender
{
[self dismissModalViewControllerAnimated:YES];
}
P.S. It works if you go to the second vievcontroller same way, as you write in -(IBAction)switchBack:(id)sender
As a guess without code, you're probably emptying or initialising your text fields in viewDidLoad, viewDidAppear or viewWillappear - do it in your viewController init instead.
I want to return a NSString * from a UIViewController, called InputUIViewController, to the previous UIViewController, called CallerUIViewController, which started InputUIViewController. I want to do it just before or when InputUIViewController calls:
[self dismissModelViewControllerAnimated:YES];
Is there a standard way to do this?
The standard way to do this would be to use a delegate.
In your InputViewController add a new delegate protocal, and a property for your delegate.
Then in your CallerUIViewController implement the delegate. Then just before your dismiss the modal view controller you can call back to your delegate.
So your InputViewController might look like this:
#protocol InputViewControllerDelegate;
#interface InputViewControllerDelegate : UIViewController {
}
#property (nonatomic, assign) id <InputViewControllerDelegate> delegate;
#end
#protocol InputViewControllerDelegate
- (void)didFinishWithInputView:(NSString *)stringValue;
#end
The method that dismisses the modal view would look something like this:
-(void)dismissSelf
{
[self.delegate didFinishWithInputView:#"MY STRING VALUE"];
[self dismissModalViewControllerAnimated:YES];
}
Then in your CallerUIViewController you would implement the InputViewControllerDelegate and the didFinishWithInputView method.
The CallerUIViewController header would look something like:
#interface CallerUIViewController : UIViewController <InputViewControllerDelegate> {
}
and your didFinishWithInputView method would be implemented something like:
- (void)didFinishWithInputView:(NSString *)stringValue
{
// This method will be called by the InputViewController just before it is dismissed
}
Just before your present the InputViewController you would set the delegate to self.
-(void)showInputViewController
{
InputViewController *inputVC = [[InputViewController alloc] init];
inputVC.delegate = self;
[self presentModalViewController:inputVC animated:YES];
[inputVC release];
}
You can do this by simply creating a NSString object as property in prvious view controller and when in second view you call dismissModelViewControllerAnimated then before it assign value to previous view controller property. This might help you -
Passing data between classes using Objective-C
I'm using a NavigationController to "push" viewControllers from the rootView of an app.
I want to use delegates to comunicate the currently loaded view and the rootViewController. I was able to do this using NSNotificationCenter, but want give a try to delegates for this particular situation, since the communication is always going to be one-to-one.
In the view that is pushed, I declared the following delegate protocole in the header file:
#import <UIKit/UIKit.h>
#protocol AnotherViewControllerDelegate;
#interface AnotherViewController : UIViewController {
id <AnotherViewControllerDelegate> delegate;
}
- (IBAction) doAction;
#property (nonatomic, assign) id delegate;
#end
#protocol AnotherViewControllerDelegate <NSObject>
- (void) doDelegatedAction:(AnotherViewController *)controller;
#end
The doAction IBAction is connected to a UIButton in the view. In my implementation file, I added:
#import "AnotherViewController.h"
#implementation AnotherViewController
#synthesize delegate;
- (IBAction) doAction {
NSLog(#"doAction");
[self.delegate doDelegatedAction:self];
}
In my RootViewController.h I added AnotherViewControllerDelegate to the interface declaration:
#interface RootViewController : UIViewController <AnotherViewControllerDelegate> {...
and this to my implementation file
- (void) doDelegatedAction:(AnotherViewController *)controller {
NSLog(#"rootviewcontroller->doDelegatedAction");
}
Unfortunately it's not working. doDelegatedAction in the rootViewController is not been called. I suspect it's because of the way I push the AnotherViewController:
AnotherViewController *detailViewController = [[AnotherViewController alloc] initWithNibName:#"AnotherViewController" bundle:nil];
[self.navigationController pushViewController:detailViewController animated:YES];
[detailViewController release];
Should I tell, in any way, to AnotherViewController that its delegate is going to be RootViewController just in the moment it's been pushed? or am I missing something else?
You need to set the delegate of AnotherViewController to the rootViewController in order for everything to be connected up properly.
If you are initializing AnotherViewController in your rootViewController it would be:
AnotherViewController *detailViewController = [[AnotherViewController alloc] initWithNibName:#"AnotherViewController" bundle:nil];
detailViewController.delegate = self;
[self.navigationController pushViewController:detailViewController animated:YES];