First of all I have to state that I am a complet newbeginner at Objective-C and iOS-programming.
Okey, so I have a simple app running, but I am facing some problems trying to switch fron one view to another. The plan is to do the "login-logic" in the view called RootView and then send the user to the DataViewController afterwards. I've tried googeling around, but no matter how I try to implement the code, it makes Xcode cry.
How can I achive the wanted effect?
Here are the following files:
RootViewController.h
#import <UIKit/UIKit.h>
#interface RootViewController : UIViewController <UIPageViewControllerDelegate>
#property (strong, nonatomic) UIPageViewController *pageViewController;
#end
RootViewController.m
#interface RootViewController ()
#end
#implementation RootViewController
- (void)viewDidLoad
{
[super viewDidLoad];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
}
#end
DataViewController.h
#import <UIKit/UIKit.h>
#interface DataViewController : UIViewController
#property (strong, nonatomic) IBOutlet UILabel *dataLabel;
#property (strong, nonatomic) id dataObject;
#end
DataViewController.m
#import "DataViewController.h"
#interface DataViewController ()
#end
#implementation DataViewController
- (void)viewDidLoad
{
[super viewDidLoad];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
}
#end
It is pretty much just an empty template, but for some reason it does not work with the solutions I've tried earier.
When you are ready to move on, in your RootViewController (can be in any method you like):
GeoPartyDataViewController *dataController = [[GeoPartyDataViewController alloc] initWithNibName:#"GeoPartyDataViewController.xib" bundle:[NSBundle mainBundle]];
[self.navigationController pushViewController:dataController animated:TRUE];
Don't forget to have #import "DataViewController.h" in your RootViewController.m.
An assumption made base on the info you gave so far, your DataViewController has an associated .xib file named GeoPartyDataViewController.xib. This is just one example. If you are working with storyboards, or some other mechanism, let me know in the comments.
First you need to add GeoPartyDataViewController.h to RootViewController.m such like
#import "GeoPartyDataViewController.h"
And now for go to GeoPartyDataViewController, you need to create instance of it .
GeoPartyDataViewController *obj =[[GeoPartyDataViewController alloc] initWithNibName:#"GeoPartyDataViewController.xib" bundle:[NSBundle mainBundle]];
[self presentViewController:obj animated:YES completion:nil];
Above code write in relavent place that you want to go on GeoPartyDataViewController.
Made it work with this:
- (void)viewDidAppear:(BOOL)animated
{
UIStoryboard *storyboard = self.storyboard;
UIViewController *mtvc = [storyboard instantiateViewControllerWithIdentifier:#"GeoPartyDataViewController"];
[self presentViewController: mtvc animated:NO completion:nil];
}
Related
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Passing model objects from one view controller to another in a navigation stack
I am trying to pass the control between two views in iphone. I have tried this and it works fine when you pass from the first view controller to the second but when i click the second, it blanks out. Why is that so? Any help is appreciated.. Thanks...
Viewcontroller.h
#import <UIKit/UIKit.h>
#import "ViewController2nd.h"
#interface ViewController : UIViewController <SecondViewControllerDelegate>
{
IBOutlet UILabel *lbl;
}
-(IBAction)passdata:(id)sender;
#end
Viewcontroller.m
#import "ViewController.h"
#import "ViewController2nd.h"
#interface ViewController ()
#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.
}
-(void) changeLabel:(NSString*)str{
lbl.text = #"Hello";
}
-(IBAction)passdata:(id)sender{
ViewController2nd *second = [[ViewController2nd alloc] initWithNibName:nil bundle:nil];
[self presentViewController:second animated:YES completion:^{ }];
}
#end
ViewController2nd.h
#import <UIKit/UIKit.h>
#protocol SecondViewControllerDelegate <NSObject>
#optional
-(void) changeLabel:(NSString*)str;
#end
#interface ViewController2nd : UIViewController{
IBOutlet UIButton *bttn;
}
-(IBAction)bttnclicked;
-(IBAction)back:(id)sender;
#end
ViewController2nd.m
#import "ViewController2nd.h"
#import "ViewController.h"
#interface ViewController2nd ()
#end
#implementation ViewController2nd
- (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 from its nib.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(IBAction)bttnclicked{
}
-(IBAction)back:(id)sender{
ViewController *first = [[ViewController alloc] initWithNibName:nil bundle:nil];
[self presentmodalViewController:first animated:YES completion:^{ }];
}
#end
Am i missing something?
If your requirement is to go to the first view change the back: method like:
-(IBAction)back:(id)sender
{
[self dismissViewControllerAnimated:YES completion:NULL];
}
Don't display the parentView as the childView of the chilkdViewController. It also makes memory issues and logical issues.
So if you want to go from the childView to parentView, dismiss the childView and never create the parent object and present it there.
I want to pass data from second tab to first tab using delegates.But delegate method not triggered.here is the code (I m using storyboard)
in SecondViewController.h
#import <UIKit/UIKit.h>
#class SecondViewController;
#protocol SecondViewControllerDelegate <NSObject>
-(void) sliderValueDidChanged: (SecondViewController *)controller data:(float) sliderValue;
#end
#interface SecondViewController : UIViewController{
__weak id<SecondViewControllerDelegate> delegate;
}
- (IBAction)sliderPressed:(id)sender;
#property (weak, nonatomic) IBOutlet UISlider *mySlider;
#property(weak,nonatomic) id<SecondViewControllerDelegate> delegate;
#end
in SecondViewController.m
#import "SecondViewController.h"
#interface SecondViewController ()
#end
#implementation SecondViewController
#synthesize mySlider;
#synthesize delegate;
- (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)viewDidUnload
{
[self setMySlider:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
- (IBAction)sliderPressed:(id)sender {
float value = mySlider.value;
[self.delegate sliderValueDidChanged:self data:value];
NSLog(#"%#",self.delegate);
}
#end
FirstViewController.h
#import <UIKit/UIKit.h>
#import "SecondViewController.h"
#interface FirstViewController : UIViewController<SecondViewControllerDelegate>
#property (weak, nonatomic) IBOutlet UILabel *myLabel;
#end
in FirstViewController.h
#import "FirstViewController.h"
#interface FirstViewController ()
#end
#implementation FirstViewController
#synthesize myLabel;
- (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.
SecondViewController *svc = [[SecondViewController alloc]init];
svc.delegate = self;
}
- (void)viewDidUnload
{
[self setMyLabel:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
-(void) sliderValueDidChanged: (SecondViewController *)controller data:(float) sliderValue{
myLabel.text = [[NSString alloc]initWithFormat:#"%f",sliderValue];
NSLog(#"delegate called");
}
#end
I am trying to set a slider in second tab and send the sider value to first tab which has a label. self.delegate printing null and delegate method never called.
Simply enough, as you already have the delegation code, only change the line where you create a SecondViewController object. Rather than creating a new one, you should have a reference to the one that the tab bar will show.
In the viewDidLoad of FirstViewController,
Change
SecondViewController *svc = [[SecondViewController alloc]init];
to
//assuming you have 2 view controllers in the tab bar controller, first being FirstViewController
SecondViewController *svc = [self.tabBarController.viewControllers objectAtIndex:1];
and that should do it
How do you actually get to the second tab? You're creating an instance of it in viewDidLoad, but if you switch tabs, that instance won't be used to show on screen. The system will create another instance which it'll use. You can access this by accessing the tab bar controller's viewcontrollers property and checking for SecondViewController.
EDIT: You could also question your design. I don't know much about your app, but chances are your first tab shouldn't really be the delegate for your second tab. If you want to pass along data, consider using NSNotificationCenter or persistent storage.
I have a UIViewController "NavigationViewController" that is added as a subview of my "FirstViewController" that takes up the whole screen (i.e. similar to the Flipboard Navigation controller in the iPad application). Many views are added and removed based on what selection the user makes. I want to be able to push a view controller to the "FirstViewController" navigationController from within the "many views" that are added. In this case the "FeaturedViewController" is one of those many views that can be selected. It inherits ContentViewController where the delegate protocol is defined.
TL;DR I want to access the navigationcontroller in the first view to push a view from the added subview "FeaturedViewController".
Here is a visual representation:
Here is the my code from:
Here is my current attempt that does not work. Note, I took some code out relating to the "Navigation Controller"
/* First View Controller */
#import <UIKit/UIKit.h>
#import "ContentViewController.h"
#interface ViewController : UIViewController <BaseViewDelegate, ContentViewDelegate>
{
IBOutlet UINavigationController *navigationController;
ContentViewController *contentView;
}
#property (strong, nonatomic) IBOutlet UINavigationController *navigationController;
#property (strong, nonatomic) ContentViewController *contentView;
---------------------------------------------------------
#import "ViewController.h"
#import "NavigatorViewController.h"
#import "BinViewController.h"
#implementation ViewController
#synthesize navigationController, contentView;
static NSArray *viewArray = nil;
- (void)didReceiveMemoryWarning
{
[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, typically from a nib.
self.navigationController.view.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height);
[self.view addSubview:navigationController.view];
// Navigation View is used to navigate throughout the entire application
NavigatorViewController *navController = [[NavigatorViewController alloc] init];
contentView = [[ContentViewController alloc] init];
contentView.delegate = self;
// Add the views to the array (using ARC)
viewArray = [NSArray arrayWithObjects:navController, contentView, nil];
}
-(void)displayNavigator
{
// Get the right view controller
UIViewController *viewController = [viewArray objectAtIndex:0];
// Add the subview to the view
[self.view addSubview:viewController.view];
}
-(void)pushViewController:(UIViewController *)viewController
{
NSLog(#"First View Push View Controller called");
[self.navigationController pushViewController:viewController animated:YES];
}
#end
/* Content View Controller */
#class ContentViewController;
#protocol ContentViewDelegate <NSObject>
-(void)pushViewController:(UIViewController *)viewController;
#end
#interface ContentViewController : UIViewController
{
__weak id <ContentViewDelegate> delegate;
}
#property (weak) __weak id <ContentViewDelegate> delegate;
- (void)pushView:(UIViewController *)viewController;
#end
---------------------------------------------------------
#import "ContentViewController.h"
#import "BinViewController.h"
#implementation ContentViewController
#synthesize delegate;
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
[super viewDidLoad];
}
- (void)pushView:(UIViewController *)viewController
{
NSLOG(#"Push View from ContentViewController");
if ([delegate respondsToSelector:#selector(pushViewController)])
[delegate pushViewController];
}
#end
/* View that is added to the navigator view (it inherits ContentViewController where the delegate protocol is defined)*/
#import <UIKit/UIKit.h>
#import "ContentViewController.h"
#interface FeaturedViewController : ContentViewController <CustomPagingDelegate>
#end
---------------------------------------------------------
#import "FeaturedViewController.h"
#import "BinViewController.h"
#implementation FeaturedViewController
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
[super viewDidLoad];
}
- (void) touchUpInsideItemAtIndex:(NSUInteger)itemIndex
{
// [[[[[self view] superview] superview] superview] removeFromSuperview];
NSLOG(#"Touch up inside from featured view");
BinViewController *binViewController = [[BinViewController alloc] init];
[self pushView:binViewController];
}
#end
Many to one or one to many sounds like easiest route would be to use NSNotificationCenter.
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'm using a library, which is a class that inherits from UIView. How do I programmatically create an UIViewController that uses this class, and not a normal UIView?
The ViewController's .h file looks as follows:
#import <UIKit/UIKit.h>
#import "PLView.h"
#interface HelloPanoramaViewController : UIViewController {
IBOutlet PLView * plView;
}
#property (nonatomic, retain) IBOutlet PLView *plView;
#end
The .m file as follows:
#import "HelloPanoramaViewController.h"
#implementation HelloPanoramaViewController
#synthesize plView;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do stuff here...
}
- (void)dealloc
{
[plView release];
[super dealloc];
}
#end
And then I should use a nib to let "plView variable pointing to the view".
But without using Interface Builder, how would I do this programmatically? How could I let this UIViewController create an PLView, instead of an UIView?
your UIViewController will something that looks like
#import "HelloPanoramaViewController.h"
#implementation HelloPanoramaViewController
- (void)loadView
{
self.view = [PLView plview]//or whatever it takes to create the plview.
}
- (void)viewDidLoad
{
//create more objects
}
- (void)viewDidUnload
{
//release unwanted objects that were created viewDidLoad
}
-(void) dealloc
{
// release all
[super dealloc];
}
#end
more info... here
In the place where you create your viewController, also create an instance of your custom view, and then set that view to your controller's view:
HelloPanoramaViewController *controller = [[HelloPanoramaViewController alloc] init];
PLView *view = [[PLView alloc] init];
controller.view = view;