I started my intrepid journey into learning objective-c for ios, and got as far as trying to build my view in the interface builder, when I realized that I can't link up the buttons I'm creating to my File's Owner. I have made sure that my File's owner has my view controller selected, and have tried restarting xcode and the interface builder. Here's the contents of both my .h and .m files:
My CalculatorViewController.h file:
#import <UIKit/UIKit.h>
#import "CalculatorBrain.h"
#interface CalculatorViewController : UIViewController {
IBOutlet UILabel *display;
CalculatorBrain *brain;
}
- (IBAction):digitPressed:(UIButton *)sender;
- (IBAction):operationPressed:(UIButton *)sender;
#end
And the CalculatorViewController.m file:
#import "CalculatorViewController.h"
#implementation CalculatorViewController
- (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.
}
- (void)viewDidUnload {
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void)dealloc {
[super dealloc];
}
#end
In short, every time I click on a button in my Interface Builder View, hold CTRL, and drag the blue line over to "File's Owner," nothing happens. In the tutorial I'm watching (The Stanford Fall 2010 IOS tutorials, lesson 2 - if that helps) shows File's Owner highlighting and working like a champ. Any help would be much appreciated. Thanks!
Invalid definition of IBActions. (Extra colon)
Change
- (IBAction):digitPressed:(UIButton *)sender;
- (IBAction):operationPressed:(UIButton *)sender;
To
- (IBAction) digitPressed:(UIButton *)sender;
- (IBAction) operationPressed:(UIButton *)sender;
So you want to link up your button with an IBAction? Did I get this correct? You need to right click on the button, select the event (usually Touch Up Inside) and then drag (from the circle to the right of the event) to the Owner. Now if you want to hook something up to an IBOutlet (usually you do this with UITextField etc.) you will drag the File Owner over to the control and select the outlet from the popup.
#import "CalculatorViewController.h"
#implementation CalculatorViewController
- (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.
}
- (void)viewDidUnload {
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (IBAction):digitPressed:(UIButton *)sender{
}
- (IBAction):operationPressed:(UIButton *)sender{
}
- (void)dealloc {
[super dealloc];
}
#end
There should be no colon after - (IBAction)
2 things:
There can't be any colon after - (IBAction)
Add this line to your code.
//.h file
IBOutlet UIButton *yourButtonName;
#property (nonatomic, retain)IBOutlet UIButton *yourButtonName;
/.m file
#synthesize yourButtonName;
Now drag it and you will done.
Related
I have a containerView into my viewController. My viewController has a UISegmentedControl.
How can I send this selectedSegmentIndex selected at this moment and everytime when I change this?
I', trying with a property in the next class with prepareForSegue but this only send on first load..
Thanks!
Then Edit I'm getting: -[ViewController containerViewDidChangeSegmentIndex:]: unrecognized selector sent to instance 0x7f8db16286d0
FirstViewController (This contains A select and a containerView)
ViewController.h
#interface ViewController : UIViewController
#property (weak, nonatomic) IBOutlet UISegmentedControl *select;
#property (weak, nonatomic) IBOutlet UIView *container;
#property(nonatomic, assign) ContainerViewController * classLevelReference;
#end
ViewController.m
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[_select addTarget:self action:#selector(segmentChanged:) forControlEvents:UIControlEventValueChanged];
}
- (void)segmentChanged:(UISegmentedControl *)segment{
//since you've reference to your container view here, you can directly call its method here:
[self.classLevelReference containerViewDidChangeSegmentIndex:segment.selectedSegmentIndex];
}
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
//don't forget to check the segue id, if you've multiple segues
ContainerViewController *containerView = [segue destinationViewController];
self.classLevelReference = self;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
ContainerViewController.h
#interface ContainerViewController : UIViewController
- (void)containerViewDidChangeSegmentIndex:(NSInteger)updatedIndex;
#end
ContainerView.m
#implementation ContainerViewController
- (void)containerViewDidChangeSegmentIndex:(NSInteger)updatedIndex{
//Do whatever you want with your updated index
NSLog(#"changing");
}
#end
You might want to make a method in your ContainerViewController.h like this:
#interface ContainerViewController:UIViewController
//.....other implementation here.
- (void)containerViewDidChangeSegmentIndex:(NSInteger)updatedIndex;
#end
Now implement this method in your ContainerViewController.m like this:
- (void)containerViewDidChangeSegmentIndex:(NSInteger)updatedIndex{
//Do whatever you want with your updated index
}
Now in your prepare for segue, save the reference to your ContainerViewController in a class-level variable :
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
//don't forget to check the segue id, if you've multiple segues
ContainerViewController *containerView = [segue destinationViewController];
self.classLevelReference = containerView;
}
Lastly in the FirstViewController.m, tell the container view when segment index changes.
- (void)viewDidLoad{
//.....your other implementation here.....
//add a listener to your segment's value changed action
[youregements addTarget:self action:#selector(segmentChanged:) forControlEvents:UIControlEventValueChanged];
}
- (void)segmentChanged:(UISegmentedControl *)segment{
//since you've reference to your container view here, you can directly call its method here:
[self.classLevelReference containerViewDidChangeSegmentIndex:segment.selectedSegmentIndex];
}
Important: you might've different names for the ContainerViewController and FirstViewController in your case, just apply the changes carefully.
Happy coding!
Im new to programming with objective C and am working on moving data between View controllers. I am wondering if Bi-directional flow of data (variables) between ViewControllers is possible.
I can move data backwards (to the presentingViewController / sourceViewController) however i cannot move data forward (to the presentedViewController / destinationViewController).
I have made a simple case scenario (involving strings to get a principle of the idea) of this and it involves updating a UItextField on the destinationViewController using a UILabel in the sourceViewController and vice-versa.
I CANNOT update the UITextField using the UILabel, but can update the UILabel using the UITextField.
I have made Logs of different statements to track the variable values however when I switch ViewControllers the variables Data returns to null even if they are marked as strong.
Can you please offer any guidance, its been tearing away at my mind, or am I missing something obvious? I don't get why I keep getting a (null) value (in my NSLog) when I switch ViewControllers.
My sourceViewController / presentingViewController is named "ViewController."
My destinationViewController / presentedViewController is named "Gears2ViewController".
I have attached my code files below:
ViewController.h:
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController
#property (strong, nonatomic) IBOutlet UILabel *outputLabel;
- (IBAction)ExitToHere:(UIStoryboardSegue *)sender;
#end
ViewController.m:
#import "ViewController.h"
#import "Gear2ViewController.h"
#interface ViewController ()
- (IBAction)changeItem:(id)sender;
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)changeItem:(id)sender {
Gear2ViewController *G2VC=[[Gear2ViewController alloc] init];
G2VC.peterSido=[NSString stringWithFormat:#"%#",self.outputLabel.text];
[self performSegueWithIdentifier:#"toGear2" sender:self];
NSLog(#"ViewController UILabel reads %#",G2VC.peterSido);
}
- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
}
- (IBAction)ExitToHere:(UIStoryboardSegue *)sender {
}
#end
Gears2ViewController.h:
#import <UIKit/UIKit.h>
#import "ViewController.h"
#interface Gear2ViewController : UIViewController
#property (strong, nonatomic) NSString *peterSido;
#end
Gears2ViewController.m:
#interface Gear2ViewController ()
#property (strong, nonatomic) IBOutlet UITextField *updatedOutput;
- (IBAction)updateOutput:(id)sender;
#end
#implementation Gear2ViewController
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
NSLog(#"Gears2ViewController ViewDidAppear reads %#",self.peterSido);
}
- (void)viewDidLoad {
[super viewDidLoad];
NSLog(#"Gears2ViewController ViewDidLoad responds %#",self.peterSido);
// Do any additional setup after loading the view.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)updateOutput:(id)sender {
self.peterSido = self.updatedOutput.text;
((ViewController *)self.presentingViewController).outputLabel.text = self.peterSido;
NSLog(#"Gears2View Controller updating ViewController UILabel reads %#",self.peterSido);
}
#end
NSLog:
2015-06-29 18:52:58.798 testerBeta[21735:645772] Gears2ViewController ViewDidLoad responds (null)
2015-06-29 18:52:58.799 testerBeta[21735:645772] ViewController UILabel reads I like Pie
2015-06-29 18:52:59.317 testerBeta[21735:645772] Gears2ViewController ViewDidAppear reads (null)
2015-06-29 18:53:12.651 testerBeta[21735:645772] Gears2View Controller updating ViewController UILabel reads No I dont
Quite Lengthy but Thanks in Advance!!!
You want to pass the data in prepareForSegue:, like so:
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)__unused sender
{
if ([[segue identifier] isEqualToString:#"toGear2"])
{
Gear2ViewController *controller = (Gear2ViewController *)segue.destinationViewController;
controller.peterSido = self.outputLabel.text;
}
}
The reason why is that the segue instantiates the presented view controller for you, and you then set the property of the instantiated view controller which the segue will present.
To pass the data back, you can use an unwind segue, which can get the value from the presented view controller's property.
- (IBAction)unwindFromGear2:(UIStoryboardSegue *)segue
{
Gear2ViewController *controller = (Gear2ViewController *)segue.sourceViewController;
self.outputLabel.text = controller.peterSido;
}
This is the proper way to pass data back and forth via segues. Gear2ViewController shouldn't be setting properties on its presentingViewController.
Update:
The preferred way to test that a property isn't nil is like this:
if (self.peterSido)
{
self.updatedOutput.text = self.peterSido;
}
else // No need for if test here
{
self.updatedOutput.text = #"";
}
That's the long form, but the assignment and if test can be more concisely written as:
self.updatedOutput.text = self.peterSido ?: #"";
When you declare any variable as #property then you need to synthesize it in .m file .
You have declared your outputLabel as #property but you missed to synthesize it in .m file.
When you synthesize any variable then it allows you to get and set the values to it .
Do it it will help you.
Thank you.
In my nib, I have a UITextView component.
In my UIViewController I have a UITextView member field and I have used IB to make sure that the two are connected (at least I think I did that by dragging from "Files Owner" and dropping it on the UITextView in IB and selecting my member variable).
Now, when I update the text via setText:, the UITextView still remains blank.
When I break into my code, the member variable (called textView) is nil.
So I am guessing I have not used IB correctly. How can I make sure that this variable is connected to the UITextView graphic element?
Here is the code
// My interface looks like
#import <UIKit/UIKit.h>
#interface DetailsController : UIViewController
{
UITextView *textView;
}
#property (nonatomic, retain) IBOutlet UITextView *textView;
#end;
// and the implementation
#import "DetailsController.h"
#implementation DetailsController
#synthesize textView;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self)
{
// Custom initialization
}
return self;
}
- (void)dealloc
{
[super dealloc];
}
- (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 (interfaceOrientation == UIInterfaceOrientationPortrait);
}
// used pressed the "Done" button
- (IBAction)done
{
[self dismissModalViewControllerAnimated:YES];
}
- (void)setDetails: (NSString *)detail withQuote:(NSString *)quote
{
NSLog(#"%#", textView);
[textView setText:detail];
}
#end
save nib file after connecting outlet, build project and run, it should work if it's connected
I can't see agere you are calling setText, but I think that you try to do it in the initializer. GUI code should not be done before the viewDidLoad in the case of using XIB's or loadView if you make your GUI programatically, or the other viewWill/viewDid... methods.
The reason is because the views are not loaded before they are actually needed, it is called lazy loading. You should Google that for more info.
Hey guys I'm a newbie developer with cocoa and I'm Trying to create a simple app. which display 4 differents pages that you can select via a tab bar.
My Problem: I made a UIButton on the First/Home page (==>FirstView.xib) with IB and i tried to link it to my second page (==>SecondView.xib) with some code found on the net.
The thing is that i can build my code but nothing happens when I try to click on my button, can you help me ?
Code for FirstView.h:
#import <UIKit/UIKit.h>
#interface FirstViewController : UIViewController {
UIButton *button;}
#property (nonatomic, retain) IBOutlet UIButton *button;
- (IBAction)goToViewTwo;
#end
Code for FirstView.m:
#implementation FirstViewController
#synthesize button;
- (IBAction)goToViewTwo {
SecondViewController *SecondView= [[SecondViewController alloc] initWithNibName: #"SecondView" bundle:[NSBundle mainBundle]];
[self.navigationController pushViewController:SecondView animated:YES];
}
- (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.
}
- (void)dealloc {
[super dealloc];
[button release];
}
#end
About the outlets in FIrstVIew.xib:
I linked "Touch Up Inside" to "goToViewTwo" and "b^utton" to "File's Owner'
I'm under the impression this is in a tab bar where each tab bar button displays a .xib file. If this is the case, the solution is fairly simple. Your tabBarController manages your views in an array of view controllers. To switch between them, your IBAction method should be the following:
- (IBAction)goToViewTwo {
self.tabBarController.selectedIndex = 1;
}
This tells your tab bar controller to switch from your current view controller (at index 0) to the second (at index 1)
Ok, so I'm a relative noob with Objective-C/iOS programming, so hopefully someone with more knowledge here can help me out.
I have an iPad application using the SplitViewController template (with Core Data). I created another UIViewController (with xib file) called PlayerViewController. This View has several UILabel components on it.
I have a list of players that show up in the RootViewController (UITableView) and when you select a player, I programmatically create a PlayerViewController (in DetailViewController), pass it the NSManagedObject that was passed to the DetailViewController, try to set the text of one of the labels on the PlayerViewController's view, and then add it as a subview to the DetailViewController.
All of this works great except for the setting the text of the label on the PlayerViewController's view. I'm not sure what I'm doing wrong. I have used NSLog to confirm that the NSManagedObject is not nil and that the NSManagedObject property I'm trying to use has the correct text.
I'm at a loss here. Any help would be greatly appreciated. (Code follows):
This method is in the DetailViewController.m file:
- (void)configureView {
// Update the user interface for the detail item.
PlayerViewController *player = [[PlayerViewController alloc] init];
player.player = detailItem;
[self.view addSubview:player.view];
}
This method is called when the user selects an item from the RootViewController (This functionality, calling of configureView, is setup by the template and I haven't changed it).
Setting the player property of the PlayerViewController to object detailItem is handled in the setPlayer method of that class.
- (void)setPlayer:(NSManagedObject *)managedObject {
if (player != managedObject) {
[player release];
player = [managedObject retain];
// Update the view.
[self configureView];
}
}
I then have a configureView method as well in PlayerViewController that sets the text of the label:
- (void)configureView {
nickName.text = [[player valueForKey:#"Nickname"] description];
NSLog(#"Nickname %#", [[player valueForKey:#"Nickname"] description]);
NSLog(#"Nickname %#", nickName.text);
}
Ok, so the first NSLog statement prints the desired value, but the text of the UILabel (called nickName) returns nil.
The following is the full PlayerViewController.h & .m files:
PlayerViewController.h:
#import <UIKit/UIKit.h>
#import <CoreData/CoreData.h>
#interface PlayerViewController : UIViewController {
NSManagedObject *player;
IBOutlet UILabel *nickName;
IBOutlet UILabel *goalCount;
IBOutlet UILabel *assistCount;
IBOutlet UILabel *timeInGame;
}
#property (nonatomic, retain) IBOutlet UILabel *nickName;
#property (nonatomic, retain) IBOutlet UILabel *goalCount;
#property (nonatomic, retain) IBOutlet UILabel *assistCount;
#property (nonatomic, retain) IBOutlet UILabel *timeInGame;
#property (nonatomic, retain) NSManagedObject *player;
#end
PlayerViewController.m:
#import "PlayerViewController.h"
#implementation PlayerViewController
#synthesize nickName, goalCount, assistCount, timeInGame, player;
#pragma mark -
#pragma mark Managing the detail item
/*
When setting the player item, update the view
*/
- (void)setPlayer:(NSManagedObject *)managedObject {
if (player != managedObject) {
[player release];
player = [managedObject retain];
// Update the view.
[self configureView];
}
}
- (void)configureView {
nickName.text = [[player valueForKey:#"Nickname"] description];
NSLog(#"Nickname %#", [[player valueForKey:#"Nickname"] description]);
NSLog(#"Nickname %#", nickName.text);
}
/*
// The designated initializer. Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
if ((self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil])) {
// Custom initialization
}
return self;
}
*/
/*
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
[super viewDidLoad];
}
*/
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
// Overriden to allow any orientation.
return YES;
}
- (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.
}
- (void)viewDidUnload {
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void)dealloc {
[super dealloc];
}
#end
I'm sure I'm just missing something trivial, but I can't figure it out, and haven't been able to find any answers searching the web.
Thanks for any help!
Ok, so after playing with this for a bit and searching and searching around, I have gotten the answer to my problem. It turns out all the code I had was fine except the location of one statement. My call to configureView in PlayerViewController.m needed to be in viewDidLoad() not in the setPlayer() method. It all works great now.
Change the configureView method to that :
- (void)configureView {
nickName.text = (NSString*)[player valueForKey:#"Nickname"];
}
Yes, better place to call method is
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[self configureView];
}
(void)setPlayer:(NSManagedObject *)managedObject called before your nib files loaded.