for exercise I'm trying to develop a simple iPhone application based on a tab bar from scratch, but I had some problem..
I've follow up these steps: http://www.techotopia.com/index.php/Creating_an_iPhone_Multiview_Application_using_the_Tab_Bar
The app loads correctly the three views until there's no connection within; if I connect any outlets or action to a label or button of the subviews, the app crash.
For example, my firstView.h contains:
#import <UIKit/UIKit.h>
#interface firstView : UIViewController {
IBOutlet UILabel *resultLabel;
}
-(IBAction)randomizeAction;
#property (nonatomic , retain) IBOutlet UILabel *resultLabel;
#end
and the firstView.m
-(IBAction)randomizeAction:(id)sender
{
//NSInteger rand = arc4random() % 75;
//resultLabel.text = [ [NSString alloc] initWithFormat:#"Random integer: #%",rand];
UIAlertView *alert = [ [UIAlertView alloc] initWithTitle:#"Yeah!" message:#"Yeah" delegate:self cancelButtonTitle:#"ok" otherButtonTitles:nil ];
[alert show];
[alert release];
}
If I connect a label to the resultOutlet or a button to the "randomizeAction" method, the app crash when I switch to the related views..
Where is the mistake?
in .h file you declare a property to be IBOutlet twice. As I don't think this causes the problem but it's just unnecessary. Also you declared randomizeAction in the .h file wihout the parameter and you implemented it with a parameter.
Your code should look like this:
#import <UIKit/UIKit.h>
#interface firstView : UIViewController {
UILabel *resultLabel;
}
#property (nonatomic , retain) IBOutlet UILabel *resultLabel;
-(IBAction)randomizeAction:(id)sender;
#end
and the firstView.m
-(IBAction)randomizeAction:(id)sender
{
//do stuff
}
From that error message it looks like your view controller isn't hooked up properly in Interface Builder. Are you sure your view controller (File's Owner in IB) is identified as an instance of firstView? Check what class it is in the Identity Inspector in XCode.
Also it would be helpful if you can show the code where your view controller is declared and created (most likely in the App Delegate).
I'm not sure, but I think you have to change this:
#interface DetailViewController : UIViewController
To:
#interface firstView : UIViewController
Related
I'm new on this, and I would like to get some advice because I don't know what I'm doing wrong.
I want to make an app in xcode, with a UIView with some items, and when you do something, another UIView (smaller than the first) pops up above the first UIView. The popup UIView would be a customized class.
I have started with the UIViewController template and the initial UIView, and I have linked all the items in the .storyboard, and it works. But when I create my own UIView class (from objective-C class), put the second UIView over the first in the storyboard and link it to my class, something goes wrong.
The UIView appears, but when I try to set it to hidden, it doesn't answer. It's like it's not receiving the messages, so I think I don't link it well programmatically and just appears because of the storyboard.
I don't know if I have to create another UIViewController instead of the UIView, or if this is the correct path.
Can anybody explain me a little, or just write a little code snippet with the instantiation of the second view and adding it?
Lots of thanks!!
(I paste some code, of the declaration in .h and instantiation in .m)
#import <UIKit/UIKit.h>
#import "EditView.h"
#interface ReleaseViewController : UIViewController <UIWebViewDelegate, UISearchBarDelegate> {
IBOutlet UIWebView *web;
IBOutlet UISearchBar *search;
IBOutlet EditView *evHack;
}
#property (nonatomic, retain) IBOutlet UIWebView *web;
#property (nonatomic, retain) IBOutlet UISearchBar *search;
#property (nonatomic, retain) IBOutlet EditView *evHack;
#end
- (void)viewDidLoad
{
[super viewDidLoad];
search.delegate = self;
web.delegate = self;
evHack = [evHack initWithFrame:CGRectMake(0, 44, 320, 377)];
[evHack setHidden:YES];
}
EditView Class (I still have nothing):
#import <UIKit/UIKit.h>
#interface EditView : UIView
#end
#import "EditView.h"
#implementation EditView
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
NSLog(#"View created");
}
return self;
}
/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
// Drawing code
}
*/
#end
initWithFrame only works when you alloc/init an app. If its already initialized, in this case by the storyboard, just set its frame:
evHack.frame = CGRectMake(0,44, 320, 377);
I don't know what it looks like in IB, But setting its frame in code may be redundant if you set it in IB too. To check whether evHack is hooked up right, NSLog evHack in viewDidLoad. If you get nil back, it's not hooked up right.
I'm running into a wall trying to resize the Hosting View. The problem is I either get a full-screen plot or a blank screen. I'm hoping to get some leads to fix this problem:
I'm using Xcode 4 | IOS 4.3 | Recently downloaded core plot using hg:
I have two xib files (MainWindow & my ViewController)
My ViewController.xib file contains two objects: a View and Hosting View both at the same level:
+-View
+-Graph Hosting View
I get no erros in my code, but all I get a blank screen. I've searched for 3 days how to get around this problem, but haven't found something that works.
My xAppDelegate.h
#import <UIKit/UIKit.h>
#class CorePlotTestViewController;
#interface CorePlotTestAppDelegate : NSObject <UIApplicationDelegate> {
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet CorePlotTestViewController *viewController;
#end
My ViewController.h
#import <UIKit/UIKit.h>
#import "CorePlot-CocoaTouch.h"
#interface CorePlotTestViewController : UIViewController <CPTPlotDataSource>
{
CPTXYGraph *graph;
NSMutableArray *dataForPlot;
CPTGraphHostingView *graphView;
}
#property(readwrite, retain, nonatomic) NSMutableArray *dataForPlot;
#property(nonatomic, retain)IBOutlet CPTGraphHostingView* graphView;
My ViewController.m
#import "CorePlotTestViewController.h"
#interface CorePlotTestViewController(private)
- (void) configureTableHeader;
#end
#implementation CorePlotTestViewController
#synthesize dataForPlot;
#synthesize graphView;
-(void)dealloc
{
[dataForPlot release];
[super dealloc];
}
- (void)viewDidLoad {
[super viewDidLoad];
[self configureTableHeader];
}
- (void) configureTableHeader
{
// here I implement the contents of the Hosting View
graph = [[CPTXYGraph alloc] initWithFrame: CGRectZero];
CPTGraphHostingView *hostingView = [(CPTGraphHostingView *)[CPTGraphHostingView alloc]
initWithFrame:CGRectZero];
[self.view addSubview:hostingView];
...
// etc
...
}
In your code, you initialize the hosting view using a CGRectZero frame, which is basically a frame with an origin at (0,0) and both a width and a height of 0 px. It is the reason why you don't see the graph at all when you run your project.
If you gave a custom size and location to the hosting view in Interface Builder, it is overridden by this code.
By the way, I'm not sure why you want to add the hosting view to the controller's view in the code. You just need to layout both components using Interface Builder, giving the hosting view the size and the location you want it to have.
Last thing : why do you add a 'T' to Core-Plot class names ? CPTPlotDataSource should simply be CPPlotDataSource; CPTXYGraph: CPXYGraph; etc.
Im new to iphone development and after lots of reading on it im still trying to figure out how UIViews operate properly. I have been playing about with it and i this is where i am at so far:
I have created a new xcode project using the view-based application. I have my MMAppViewController classes and i created a new UIViewController subclass called "Level1View".
There is a button titled "Level 1" that takes me to the "Level1View" viewController. In this viewController there is there is a "next" button, a "main menu" button (that returns to MMAppViewController) and there is a label, currently titled "Level 1".
My problem is that the code i have used to change the title of label does not work! Does anyone know why this is? Here is my code:
#class MMAppViewController;
#interface MMAppAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
MMAppViewController *viewController;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet MMAppViewController *viewController;
#end
and
#implementation MMAppViewController
-(IBAction)pushLevel1{
Level1View *level1View = [[Level1View alloc] initWithNibName:nil bundle:nil];
[self presentModalViewController:level1View animated:YES];
}
...
and
#import <UIKit/UIKit.h>
#interface Level1View : UIViewController {
IBOutlet UILabel *labelTitle;
}
-(IBAction)pushBack;
-(IBAction)pushNext;
#end
and
#import "Level1View.h"
#import "MMAppViewController.h"
#implementation Level1View
-(IBAction)pushBack{
MMAppViewController *MainView = [[MMAppViewController alloc] initWithNibName:nil bundle:nil];
[self presentModalViewController:MainView animated:YES];
}
-(IBAction)pushNext{
[labelTitle setText:(#"Thanks for playing :)")];
}
- (void)didReceiveMemoryWarning {
...
Currently the app runs but the label wont change when i hit the "next" button. Can anyone help?
are you sure a UINavigationController isn't a better tool for the job you want to do? That will make it easy for you to manage a stack of UIView objects.
That said, have you tried adding logging to make sure your pushNext method is getting called? where is labelTitle declared? Did you use a XIB or not?
Did you bind the Label in Interface Builder to the labelTitle outlet in your Level1View?
If you forget that step, the outlets won't work. Even after several years, I still forget this step sometimes.
--Mike
are you sure you connected the label in IB?
and if you set a property "#property (nonatomic, retain) IBOutlet UILabel *labelTitle;" in Level1View.h you can access it from Main View:
Level1View *level1View = [[Level1View alloc] initWithNibName:nil bundle:nil];
[self presentModalViewController:level1View animated:YES];
level1View.labelTitle.text = #"something";
[level1View release];
The other thing you shouldn't present the Main View Controller again instead dismiss the Level1View with:
#implementation Level1View
-(IBAction)pushBack{
[self dismissModalViewControllerAnimated:YES];
}
//
and maybe the problem is [[Level1View alloc] initWithNibName:nil bundle:nil] you have to specify the nib you want to load e.g. [[Level1View alloc] initWithNibName:#"Level1View" bundle:nil]
Declare labelTitle as a property in your header file, and synthesize labelTitle in your .m - as long as labelTitle is hooked up through interface builder the rest of your code is fine.
.h
#property (nonatomic, retain) IBOutlet UILabel *labelTitle;
.m
#synthesize labelTitle;
Then your setter call will work. (also, dot-notation works for synthesized properties so you may as well use it)
change
[labelTitle setText:(#"Thanks for playing :)")];
to
labelTitle.text = #"Thanks for playing :)";
Synthesizing a property will create setter and getter methods at runtime. Read: The Objective-C Programming Language
I have a UINavigationController as one of the views inside a tab bar control. It looks fine, and I have a UIBarButtonItem that is supposed to load a subview. I have the button wired up to an IBAction that calls pushViewController but when I do this nothing happens. It doesn't crash or anything.. it just doesn't do anything. I've tried: using different view controllers as the subview (no luck). Does anybody have any suggestions? Here is my code:
Header file:
#import <UIKit/UIKit.h>
#import "FSSettings.h"
#import "MeasureSelector.h"
#import "Dashboard.h"
#interface DashboardNavigationController : UIViewController {
IBOutlet UINavigationController *navController;
IBOutlet UINavigationBar *navBar;
IBOutlet UIBarButtonItem *measureButton;
}
#property (nonatomic, retain) IBOutlet UINavigationController *navController;
#property (nonatomic, retain) IBOutlet UINavigationBar *navBar;
#property (nonatomic, retain) IBOutlet UIBarButtonItem *measureButton;
- (IBAction) showMeasureScreen:(id)sender;
#end
And the .m file containing the action:
// Displays the measure screen
- (IBAction) showMeasureScreen:(id)sender
{
NSLog(#"Loaded measure screen");
MeasureSelector *msel = [[MeasureSelector alloc] initWithNibName:#"MeasureSelector" bundle:nil];
[[self navigationController] pushViewController:msel animated:YES];
NSLog(#"Done.");
}
When I click the button nothing happens (but I do see the log messages). I can do this over and over with no ill effects, however.
The navigationController property of UIViewController refers to the nav controller of which the UIViewController is part of the hierarchy. If I understand the scenario correctly, DashboardNavigationController manages the view that is the container for the UINavigationController, so it makes sense that this property would be nil.
Use the outlet you created to access the nav controller from outside of the nav controller's hierarchy.
I'm a beginner programmmer, this is for xcode - iPhone. although i made alot of my iPhone app but i seem to lack some understanding of how a simple communication might work.
Specially when I've got 2 ViewControllers.
And I wana call one function of a ViewController from another ViewController. Both are under a tabbarController. What I want to achieve is When I'm in ViewA, after tapping on a tableCell, I Should Invoke a method of ViewB and the NavigationBar of ViewB pushes to viewDetail.
The Following is the code i'm using
in ViewControllerA.h (where I'm calling a method)
#class ViewControllerB;
#interface SmartDDxViewController : UIViewController {
IBOutlet UITableView *tableView;
ViewControllerB *xViewController;
}
#property (nonatomic, retain) UITableView *tableView;
#property (nonatomic, retain) ViewControllerB *xViewController;
And this is what I use to invoke it..ViewControllerA.m
ViewControllerB *ddViewController = [[ViewControllerB alloc] init];
self.xViewController = ddViewController;
[xViewController InitialiseDetailWithId:2 title:#"HEYA"];
Heres the InitialiseDetailWithId code: in ViewControllerB.m
-(void)InitialiseDetailWithId:(NSInteger)pkey title:(NSString *)tt{
NSLog(#"InitialiseDetailC=========================================");
AppDelegate *appDelegate = (Smart_DifferentialsAppDelegate *)[[UIApplication sharedApplication] delegate];
[appDelegate GetConditionDetailsWithId:pkey];
DDisViewController *viewController= [[DDisViewController alloc] initWithNibName:#"DetailView" bundle:nil];
viewController.title = tt;
[self.NavBar pushViewController:viewController animated:YES];
//[tt release];
[viewController release];
viewController = nil;
[self say:#"HEYA"]; //this is ALERTVIEW box that displays HEYA
}
I'm getting all information fine, and the alertview does get displayed. But when I chose that View in TabBar, its not pushed.
Do not use direct access between view controllers, instead use the delegate pattern. Define your controller like this:
#protocol ViewControllerAInitDelegate;
#interface ViewControllerA : UIViewController {
IBOutlet UITableView *tableView;
id<ViewControllerAInitDelegate> initDelegate;
}
#property (nonatomic, retain) UITableView *tableView;
#property (nonatomic, assign) ViewControllerAInitDelegate *initDelegate;
#end
#protocol ViewControllerInitDelegate
-(void)initializeDetailWithId:(NSInteger)pkey title:(NSString)tt;
#end
So in
Now let your application delegate conform to the ViewControllerInitDelegate protocol. It should look something like this:
#interface AppDelegate : NSObject <UIApplicationDelegate, ViewControllerInitDelegate> {
IBOutlet UITabBarControler* tabBarController;
IBOutlet ViewControllerA* controllerA;
IBOutlet ViewControllerB* controllerB;
}
#end;
The AppDelegate should know about both ViewControllerA, and ViewControllerB, but neither of the view controller should know about each other. This way it will be much easier to debug and extend your app.
//current view controller index
int currentVCIndex = [self.navigationController.viewControllers indexOfObject:self.navigationController.topViewController];
//previous view controller (index -1)
AccountViewController *account = (AccountViewController *)[self.navigationController.viewControllers objectAtIndex:currentVCIndex - 1];
(access to anything you want)
account.property = object;
[account doSmthng];
In each of your view controllers, you might want to add a instance variable/property to keep track of the other view controller.
you might have for example:
#interface ThisViewController : UIViewController {
SomeViewController *sViewController;
// other instance variables
}
#property (nonatomic, retain) SomeViewController *sViewController;
This not only makes it easier to call methods from the other view controller and access its public properties, but it also allows you an easier way of flipping between the two (with or without animation).