I am trying to segue to another screen from a uitableview in iOS5. I have set up a delegate etc. which seems to work (the segue occurs) but I think I need to "set delegate to initialize the data I want to display in the new screen. I get a NSInvalidArgumentException error though when I call it is prepareforsegue.
Here is the code for the uitableview part...
#import "iTanksV2ListViewController.h"
#import "tank.h"
#import "tankDetailViewController.h"
#interface iTanksV2ListViewController ()
#property tank *selectedTank;
#end
#implementation iTanksV2ListViewController
#synthesize tanks = _tanks;
#synthesize tankTableView = _tankTableView;
#synthesize delegate = _delegate;
#synthesize selectedTank = _selectedTank;
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
self.tankTableView.delegate = self;
self.tankTableView.dataSource = self;
}
-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if([segue.identifier isEqualToString:#"Show Tank Details"])
{
UILabel *myLabel = [[UILabel alloc] init];
myLabel.text = self.selectedTank.tankNumber;
[segue.destinationViewController setTankNumberLabel:myLabel];
[segue.destinationViewController setDelegate:self]; ///this is where it fails!!!
}
}
#pragma mark - Table view delegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
self.selectedTank = [self.tanks objectAtIndex:indexPath.row];
[self.delegate iTanksListViewController:self choseTank:self.selectedTank];
}
and then in the detail view I use the following...
-(void)iTanksListViewController:(iTanksV2ListViewController *)sender choseTank:(id)tank
{
self.tankToShow = tank;
}
but this doesn't get called - presumably because i don't successfully call the setdelegate method?!
You must not have synthesized your delegate property. Also, make sure that your header file properly has the delegate protocol referenced like
#interface TankDetailViewController : UITableViewController <DELEGATEPROTOCOL>
I thought I had... this snippet is from the itanksv2listviewcontroller header:
#interface iTanksV2ListViewController : UITableViewController
#property (nonatomic, strong) NSArray *tanks;
#property (weak, nonatomic) IBOutlet UITableView *tankTableView;
#property (weak, nonatomic) id <iTanksV2ListViewControllerDelegate> delegate;
#end
and this from the m file :
#synthesize delegate = _delegate;
and this is what I have put in the detailview m file:
#interface tankDetailViewController () <iTanksV2ListViewControllerDelegate>
#end
Related
I've problems passing data to a new view controller.
I've two VC. In the "FirstVC" there is a table view with dynamic prototypes cells. The generic cell contains a label and a button and it's assigned to its own class "GenericCell". I want to pass to the SecondVC the text of the cell label when I press the button, but the app crashes with errors:
Unknown class _TtC13testTableView37SecondVC in Interface Builder file.
UIViewController setMyString:]: unrecognized selector sent to instance 0x7fa05e418110
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIViewController setMyString:]: unrecognized selector sent to instance 0x7fc8add05710
I tried:
To use the segue (with prepareForSegue method) outside the getText method
1a. Pushing the VC from the outside of the getText method
Implementing and calling set/get method of myString
Adding attributes to myString property
but the app crashes the same.
GenericCell.h
#import <UIKit/UIKit.h>
#protocol MyCellDelegate
-(void)getText:(NSString *)text;
#end
#interface GenericCell: UITableViewCell
#property (weak, nonatomic) IBOutlet UILabel * label;
#property (assign, nonatomic) id <MyCellDelegate> delegate;
#end
GenericCell.m
#import "GenericCell.h"
#interface GenericCell()
#end
#implementation GenericCell
- (IBAction)buttonPressed {
if (self.delegate) {
[self.delegate getText:self.label.text];
}
}
#end
FirstVC.m
#import "FirstVC.h"
#import "GenericCell.h"
#import "SecondVC.h"
#interface FirstVC() <UITableViewDataSource,UITableViewDelegate, MyCellDelegate>
#property (weak, nonatomic) IBOutlet UITableView *tableView;
#property NSString * idToPass;
#end
#implementation FirstVC
NSMutableArray<NSString *> *array;
- (void)viewDidLoad {
array = [[NSMutableArray alloc]initWithObjects:#"0x22", #"0x11", #"0x24", nil];
[super viewDidLoad];
self.tableView.dataSource=self;
self.tableView.delegate=self;
self.tableView.rowHeight=100;
}
-(void)getText:(NSString *)text {
self.idToPass = text;
SecondVC * secondVC = [self.storyboard instantiateViewControllerWithIdentifier:#"SecondVC"];
secondVC.myString = self.idToPass;
[[self navigationController] pushViewController:secondVC animated:YES];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return array.count;
}
- (GenericCell *)tableView:(nonnull UITableView *)tableView cellForRowAtIndexPath:(nonnull NSIndexPath *)indexPath {
GenericCell * cell = [[self tableView]dequeueReusableCellWithIdentifier:#"GenericCell" forIndexPath:indexPath];
cell.delegate = self;
cell.label.text = [array objectAtIndex:indexPath.row];
return cell;
}
#end
SecondVC.h
#import <UIKit/UIKit.h>
#interface SecondVC : UIViewController
#property (weak, nonatomic) IBOutlet UILabel *label;
#property NSString * myString;
#end
SecondVC.m
#import "SecondVC.h"
#interface SecondVC ()
#end
#implementation SecondVC
- (void)viewDidLoad {
self.label.text = self.myString;
[super viewDidLoad];
}
#end
The "idToPass" is set correctly with delegation.
This work for me: in the buttonPressed method update the if statement like this
if ([self.delegate respondsToSelector:#selector(getText:)]){
[self.delegate getText:self.label.text];
}
Another option to give SecondVC the data is using
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
SecondVC * vc = segue.destinationViewController;
if ([segue.identifier isEqualToString: #"yourSegue"]) {
vc.myString = self.idToPass;
}
}
A tip I suggest is to check (with a simple if statement) if your object in SecondVC is nil or !nil
I hope this help :)
In getText method you assign text to myProperty instead myString...
It should be:
secondVC.myString = self.idToPass;
I'm having trouble figuring out why I'm getting a nil delegate for this call. It seems like I'm setting the delegate just fine.
LogoutViewController.h
#protocol SomeNewDelegate <NSObject>
#required
- (void)someMethod;
#end
#interface LogoutViewController : UIViewController
#property (nonatomic, weak) id<SomeNewDelegate> delegate;
LogoutViewController.m
- (IBAction)logoutButtonTapped:(id)sender {
NSLog(#"logout tapped");
[self.delegate someMethod];
[self dismissViewControllerAnimated:YES completion:nil];
}
MainViewController.m
#interface MainViewController () <UIScrollViewDelegate, SomeNewDelegate>
#property (nonatomic, strong) LogoutViewController *logoutVC;
#end
#implementation MainViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.logoutVC.delegate = self;
}
- (void)someMethod {
NSLog(#"someMethod");
}
someMethod never gets called and I don't see why the delegate is nil. Any help?
Use below code in viewDidload
LogoutViewController *logoutVC = [[LogoutViewController alloc]init];
logoutVC.delegate = self;
Remove LogoutViewController from property.
I have used this and its working fine.
Hope its working for you.
Edited code in .h file
#protocol syncDataDelegate <NSObject>
#required
- (void) offlineSyncProcess;
#end
#interface LoginViewController : UIViewController
{
id <syncDataDelegate> syncDelegate;
}
#property (retain) id syncDelegate;
in .m file
#implementation LoginViewController
{
// your code
}
#synthesize syncDelegate;
- (IBAction)logoutButtonTapped:(id)sender {
NSLog(#"logout tapped");
[syncDelegate offlineSyncProcess];
}
You can call delegate method from here in LoginViewController.m file from any method.
in My Delegate implementation
in .m file
#interface MainViewController ()<syncDataDelegate>
#end
#implementation MainViewController
- (void)viewDidLoad
{
[super viewDidLoad];
LoginViewController *LVC = [[LoginViewController alloc]init];
LVC.syncDelegate = self;
}
now use the delegate methode here
- (void) offlineSyncProcess
{
// your code here
}
this code is working in my project, check this in your project.
Make sure your logoutVC is not nil when you try to set the delegate property for it.
You can implement the setDelegate method in your LogoutViewController.m. Then use break point to make sure it is invoked.
Delegate is nil because your logoutVC is nil, you haven't allocated memory to the logoutvc property.
Just before self.logoutVC.delegate = self
Add following code
self.logoutVC = [[LogoutViewController alloc]init];
Everything will start working automatically.
im new to iOS and its developing .there i have used iOS delegates to pass values in between view controllers
1. Essentialinfocontroller - its got TableView
2. detailcontroller -
i want to pass values of Essentialinfocontroller to detailcontroller
to do that i used delegates but nothing print on console please help me.
Essentialinfocontroller.h
#import <UIKit/UIKit.h>
#protocol sendTestData <NSObject>
-(void)sendDataToA:(NSArray *)array;
#end
#interface Essentialinfocontroller : UIViewController<UITableViewDataSource,UITableViewDelegate>
#property (weak, nonatomic) IBOutlet UITableView *info;
#property (nonatomic,strong) NSDictionary * courses;
#property (nonatomic, strong)NSArray *coursekeys;
#property(nonatomic,strong) NSString* customeLink;
#property (nonatomic,retain)NSArray * array;
#property(nonatomic,assign)id delegate;
#end
Essentialinfocontroller.m
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
if(indexPath.row==0){
[self giveValuestoNSmutableArray];
[delegate sendDataToA:array];
}
}
-(void)giveValuestoNSmutableArray
{
array = [NSArray arrayWithObjects:#"Jill Valentine", #"Peter Griffin", #"Meg Griffin", #"Jack Lolwut",
#"Mike Roflcoptor", #"Cindy Woods", #"Jessica Windmill", #"Alexander The Great",
#"Sarah Peterson", #"Scott Scottland", #"Geoff Fanta", #"Amanda Pope", #"Michael Meyers",
#"Richard Biggus", #"Montey Python", #"Mike Wut", #"Fake Person", #"Chair",
nil];
}
detailcontroller.h
#import <UIKit/UIKit.h>
#import "Essentialinfocontroller.h"
#interface detailcontroller : UIViewController <sendTestData>
#end
detailcontroller.m
#import "detailcontroller.h"
#interface detailcontroller ()
#end
#implementation detailcontroller
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
Essentialinfocontroller * acontollerobject=[[Essentialinfocontroller alloc] initWithNibName:#"Essentialinfocontroller" bundle:nil];
acontollerobject.delegate=self; // protocol listener
[self.navigationController pushViewController:acontollerobject animated:YES];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(void)sendDataToA:(NSArray *)array
{
for (NSString *string in array) {
NSLog(#"%#", string);
}
}
#end
You've got the relationship between controllers and delegates a little backwards. A delegate is used to pass information back. Your tableViewController is the detailController's delegate, and detailController shouldn't be allocating an EssentialInfoController inside it. You're basically creating a whole new EssentialInfoController that's different from the first one.
The easiest way to pass data is just to set it when the detailController is allocated. Also, since you're using storyboards, you have to use (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender to allocate the detailController.
Here's what I would do:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
if(indexPath.row==0){
[self performSegueWithIdentifier:#"OpenDetailsController"];
}
}
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
DetailController *controller = (DetailController *)[segue destinationViewController];
NSArray *array = <your array here>;
[controller setArray:array];
}
In your storyboard, set the Storyboard Segue Identifier for that segue to "OpenDetailsController".
A delegate function is defined through a protocol, and you would have the DetailController call its delegate like this:
[self.delegate doSomething];
And in the EssentialInfoViewController you have to define the delegate function
-(void)doSomething {
}
I have a big noob problem. I new in iOS and I'm trying to do this:
I have two ViewControllers. The first one has an button that if it is pushed, control goes to a second view controller.
That works but the problem is when I try to get data in my second view controller. The UITextfield doesn't work.
I'm trying to display which I insert into textfield in the label. But THE TEXTFIELD DOESN'T WORK :(
I putted the IBOutlets succesfully in the xibs and connect the buttons with their IBActions...
This is my code:
ViewController.h
#import <UIKit/UIKit.h>
#import "SecondViewController.h"
#class SecondViewController;
#interface ViewController : UIViewController
#property (strong, nonatomic) SecondViewController *secondViewController;
-(IBAction)buttonClicked:(id)sender;
#end
ViewController.m
#import "ViewController.h"
#implementation ViewController
#synthesize secondViewController;
-(IBAction)buttonClicked:(id)sender {
self.secondViewController = [[SecondViewController alloc]initWithNibName:#"SecondViewController" bundle:nil];
[self presentViewController:self.secondViewController animated:YES completion:nil];
}
SecondViewController.h
#import <UIKit/UIKit.h>
#interface SecondViewController : UIViewController {
IBOutlet UITextField *textField;
UIButton *obtener;
IBOutlet UILabel *label;
}
#property (nonatomic, retain) IBOutlet UITextField *textField;
#property (nonatomic, retain) IBOutlet UIButton *obtener;
#property (nonatomic, retain) IBOutlet UILabel *label;
-(IBAction)obtenerClicked:(id)sender;
#end
SecondViewController.m
#import "SecondViewController.h"
#implementation SecondViewController
#synthesize obtener, textField, label;
-(IBAction)obtenerClicked:(id)sender {
label.text = textField.text;
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)didReceiveMemoryWarning
{
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return YES;
}
#end
In your SecondViewController.h, add this property:
#property(nonatomic, readwrite) NSString* myString;
now in firstViewController's onClick method, add this line
-(IBAction)buttonClicked:(id)sender {
//....... Previous code....
self.secondViewController.myString= #"String to be sent";
}
This will pass the string for you..
if you want to pass the string in text field, use this:
-(IBAction)buttonClicked:(id)sender {
//....... Previous code....
self.secondViewController.textField.text= #"String to be sent";
}
hope it will work fine for your requirement.
UPDATE:
Do the following to get expected results:
1. make your secondViewController a textView delegate.
in your secondViewController.h
replace #interface SecondViewController : UIViewController with #interface SecondViewController : UIViewController<UITextFieldDelegate>
put a button in your secondViewController & create an IBAction for it.
on Click event of button, write this:
self.label.text= self.textfield.text;
tell me if it does not work.
I'm trying to separate the UITextViewDelegate methods from the main class of my project, I created a class to manage the delegate methods, but I can not change the values of the IBOulets from the main class.
I made a test project with a ViewController and a TextFieldController, in the Storyboard I add a text field and a label. What I want to do is change the text of the label when I start to write in the text field. Here is the code:
ViewController.h:
#import <UIKit/UIKit.h>
#import "TextFieldController.h"
#interface ViewController : UIViewController
#property (strong, nonatomic) IBOutlet UITextField *textField;
#property (strong, nonatomic) IBOutlet UILabel *charactersLabel;
#end
ViewController.m:
#import "ViewController.h"
#interface ViewController ()
#property (nonatomic, strong) TextFieldController *textFieldController;
#end
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
_textFieldController = [[TextFieldController alloc] init];
_textField.delegate = _textFieldController;
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
}
#end
TextFieldController.h:
#import <UIKit/UIKit.h>
#import "ViewController.h"
#interface TextFieldController : UIViewController <UITextFieldDelegate>
#end
Text Field Controller.m:
#import "TextFieldController.h"
#interface TextFieldController ()
#property ViewController *viewController;
#end
#implementation TextFieldController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (BOOL) textFieldShouldBeginEditing:(UITextField *)textField {
NSLog(#"hello");
_viewController.charactersLabel.text = #"hello";
return YES;
}
#end
When I start writing in the text field the message "Hello" is printed in the log, but the text of the label does not change. I want to know how to change the label text value from the other class.
First change the TextFieldController.h like this:
#import <UIKit/UIKit.h>
#import "ViewController.h"
#interface TextFieldController : NSObject <UITextFieldDelegate>
{
}
#property (nonatomic, assign) ViewController *viewController;
#end
Then change your TextFieldController.m file like this:
#import "TextFieldController.h"
#interface TextFieldController ()
#end
#implementation TextFieldController
- (BOOL) textFieldShouldBeginEditing:(UITextField *)textField {
NSLog(#"hello");
self.viewController.charactersLabel.text = #"hello";
return YES;
}
#end
In the ViewController.m do like that:
#import "ViewController.h"
#interface ViewController ()
#property (nonatomic, strong) TextFieldController *textFieldController;
#end
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
_textFieldController = [[TextFieldController alloc] init];
_textFieldController.viewController = self;
_textField.delegate = _textFieldController;
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
}
#end
This will work but I personally dont like that way you took.
Good luck :)
It's failing because _viewController is nil. You need to assign the viewController property in your delegate in order to support the two way communication.
Also, I'd strongly recommend you make your delegate object a subclass of NSObject, and not UIViewController. It does nothing with controlling views. You can just manually instantiate it in your ViewController objects viewDidLoad.
In TextViewController I don't see where the viewController property (_viewController ivar) is being set so it is probably nil. You should set it when you create the TextViewController instance.
When you are navigating to other controllers using storyboad's segue then you need to implement prepareForSegue method to initialised its properties as follows
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if([segue.identifier isEqualToString:#"segue for textFieldController"])
{
TextFieldController *_textFieldController = [segue destinationViewController];
_textField.delegate = _textFieldController;
}
}
But I was wondering, why are you setting textFieldDelegate here, why can't you set in TextFieldController's viewDidLoad method as then you didn't you to implement above prepareForSegue method call?
Besides you are keeping strong reference of each other and you are creating strong retain cycle.
One more thing, following code
_textField.delegate = _textFieldController;
will not work, until textFieldController is loaded and its viewDidLoad method is being called as you are only initialising it but its outlets will not be connected until view is loaded into navigation stack.