i want to share data between views...
i have the appdelegate of tabbar application:
myappdelegate.h
#import <UIKit/UIKit.h>
#interface myappdelegate : NSObject <UIApplicationDelegate, UITabBarControllerDelegate> {
UIWindow *window;
UITabBarController *tabBarController;
NSString *result;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet UITabBarController *tabBarController;
#property (copy , readwrite) NSString *result;
#end
if i want to call with this command, there is the hint: "may not respond"....
myappdelegate *dataCenter = [(myappdelegate *)[UIApplication sharedApplication] delegate]; <<may not respond
dataCenter.result = #"msg";
result_view *resultView = [[result_view alloc] initWithNibName:#"result_view" bundle:nil];
[self.navigationController pushViewController:resultView animated:YES];
[resultView release];
result_view.m
- (void)viewDidLoad
{
myappdelegate *dataCenter = (myappdelegate*)[[UIApplication sharedApplication]delegate];
[label setText:dataCenter.result];
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
}
the program crashes...
Your code is saying that the sharedApplication is of the class myappdelegate, which indeed does not respond to delegate. Do this:
(myappdelegate *)[[UIApplication sharedApplication] delegate];
to remove the warning.
Due to Objective-C's runtime messaging, your current (warning-generating) code won't crash the app. The crash lies somewhere else.
Your first line should be
myappdelegate *dataCenter = (myappdelegate *)[[UIApplication sharedApplication] delegate];
As for the second line, I can't tell what you expect to happen. You don't have a result_array property on your myappdelegate class, so of course you can't set that property.
If you were trying to set the result property, you should have written
dataCenter.result = #"msg";
Related
I have a navigation controller residing inside a tab bar controller and whenever I try to access a class from a class within the navigation controller all my values return (null).
This is how I'm trying to do it.
AppDelegate.h
#interface AppDelegate : UIResponder <UIApplicationDelegate, UITabBarControllerDelegate> {
NSString *searchQueryA;
}
#property (strong, nonatomic) NSString *searchQueryA;
ThirdViewController.h
#import "MasterViewController.h"
#import "AppDelegate.h"
#class MasterViewController;
#interface ThirdViewController : UIViewController {
code
}
#property (strong, retain) MasterViewController *masterViewController;
ThirdViewController.m
- (IBAction)showDetail:(id)sender {
AppDelegate *appDelegate = [[AppDelegate alloc] init];
appDelegate.searchQueryA = _searchField.text;
masterViewController = [[MasterViewController alloc] initWithNibName:#"MasterViewController" bundle:nil];
[self.navigationController pushViewController:masterViewController animated:YES];
}
MasterViewController.h
#import "AppDelegate.h"
#interface MasterViewController : UITableViewController
{
NSString *searchQueryM;
}
#property (nonatomic, strong) NSString *searchQueryM;
MasterViewController.m
AppDelegate *appDelegate = [[AppDelegate alloc] init];
searchQueryM = appDelegate.searchQueryA;
NSLog(#"%#", searchQueryM);
And in the log I can see that searchQueryM is (null). If I try to access the variable in AppDelegate from another class, that isn't involved with navigation controller, then it shows perfectly fine. What am I missing?
If you need to see more code I'd be happy to provide it.
EDIT:
For legibility I'll post code changes here:
I have the delegate in my AppDelegate.h
As Leonardo pointed out I only alloc'd and init'd my AppDelegate. I changed that snippet to this:
AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
searchQueryM = appDelegate.searchQueryA;
but still no go as searchQueryM still is (null).
This is what I do with searchQueryM
MasterViewController.h
#interface MasterViewController : UITableViewController
{
NSString *searchQueryM;
}
#property (nonatomic, strong) NSString *searchQueryM;
MasterViewController.m
#synthesize searchQueryM;
I'm fairly new to Objective-C (as well as OO-programming) and should probably read a book on it, but it seems to me like there isn't a lot more to it than that. Do correct me if I'm wrong.
EDIT 2
ThirdViewController.h
#interface ThirdViewController : UIViewController {
UITextField *_searchField;
}
#property (nonatomic, strong) IBOutlet UITextField *searchField;
ThirdViewController.m
#synthesize searchField = _searchField;
...
- (IBAction)showDetail:(id)sender {
_code_
NSLog(#"%#", searchField.text);
_code_
If i type in "asd" in the searchField textfield and output it with the log I get "asd".
}
Why are you alloc init your AppDelegate ?
The AppDelegate should be accessed with:
[[UIApplication sharedApplication] delegate]
We should see how you normally initialize searchQueryM, you are getting null, probably because the AppDelegate get only allocated and init, but the logic that initialize its properties never gets called.
I am getting the following warning when I am calling other view controllers..
WindowMultivewAppDelegate might not respond to -switchView to view
This is my code in the Firstviewcontroller.m
- (IBAction)swapViews:(id)sender{
WindowMultiViewAppDelegate *delegate = (WindowMultiViewAppDelegate *)[[UIApplication sharedApplication] delegate];
SecondViewController *secondView = [[SecondViewController alloc] initWithNibName:#"SecondViewController" bundle:nil];
[delegate switchView:self toView:secondView.view];
}
this is my code in the Firstviewcontroller.h
#import <UIKit/UIKit.h>
#interface FirstViewController : UIViewController {
}
- (IBAction)swapViews:(id)sender;
#end
in the appdelegate.m
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions: (NSDictionary *)launchOptions {
initWithNibName:#"FirstViewController" bundle:nil];
[self.window addSubview:navigationController.view];
locationManager = [[CLLocationManager alloc] init];
locationManager.distanceFilter = kCLDistanceFilterNone; // whenever we move
locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters; // 100 m
if ([CLLocationManager locationServicesEnabled]) {
[locationManager startUpdatingLocation];
}
[self.window makeKeyAndVisible];
return YES;
}
in the appdelegate.h
#interface WindowMultiViewAppDelegate : NSObject <UIApplicationDelegate, CLLocationManagerDelegate , MKMapViewDelegate> {
UIWindow *window;
UINavigationController *navigationController;
CLLocationManager *locationManager;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet CLLocationManager *locationManager;
#property (nonatomic, retain) IBOutlet UINavigationController *navigationController;
#end
I have placed a UInavgationcontroller into the mainWindow.xib which leads to the rootviewcontroller which i named FirstViewController
The application quites in the secondviewcontroller when a button next is pressed which has that action inside
- (IBAction)swapNext:(id)sender
{
WindowMultiViewAppDelegate *delegate = (WindowMultiViewAppDelegate *)[[UIApplication sharedApplication] delegate];
MediaViewController *mediaView = [[MediaViewController alloc] initWithNibName:#"MediaViewController" bundle:nil];
[delegate switchView:self toView:mediaView.view];
}
What am I doing wrong??
Can anybody tell me how to connect more subviews into the UINavigationController
I want one of this subviews to be a video player - offline- and the other one to be a map which find the user"s location
I am a beginner.... thank you all when I learn I am going to help others :))
I don't see that you define the switchView: method anywhere, so it's no surprise that you get a warning about this.
I have a navigation controller that utilizes an if statement to switch between the different views, and when i run it it comes up with a warning on the line:
ROSS_APP_7AppDelegate *delegate = [[UIApplication sharedApplication] delegate];
warning: type 'id ' does not conform to the 'UITabBarControllerDelegate' protocol
I'd like some help on how to get rid of this warning.
Here is the whole if statement:
if(indexPath.row == 0)
{
MapDetailController *mapD = [[MapDetailController alloc] initWithNibName:#"MapDetailController" bundle:nil];
self.mapDetailController = mapD;
[mapD release];
mapDetailController.title = [NSString stringWithFormat:#"%#", [moreArray objectAtIndex:row]];
ROSS_APP_7AppDelegate *delegate = [[UIApplication sharedApplication] delegate];
[delegate.moreNavController pushViewController:mapDetailController animated:YES];
}
Thanks
EDIT:
Here is what my AppDelegate looks like (response to answer #2)
#import <UIKit/UIKit.h>
#class MoreNavController;
#interface ROSS_APP_7AppDelegate : NSObject <UIApplicationDelegate, UITabBarControllerDelegate> {
UIWindow *window;
IBOutlet UITabBarController *tabBarController;
IBOutlet MoreNavController *moreNavController;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet UITabBarController *tabBarController;
#property (nonatomic, retain) IBOutlet MoreNavController *moreNavController;
#end
You probably forgot to have your app delegate conform to the UITabBarControllerDelegate protocol.
To implement it, your appDelegate header should look like this (the #interface declaration is the relevant line):
#import ...
#interface ROSS_APP_7AppDelegate : AppDelegate_Shared <UITabBarControllerDelegate>
{
....
}
#property(nonatomic, retain) .....
#end
You might be using AppDelegate_Shared / AppDelegate_iPhone / AppDelegate_iPad so bear in mind that the above example considers a shared app delegate
EDIT:
After seeing your comment,
Try replacing:
ROSS_APP_7AppDelegate *delegate = [[UIApplication sharedApplication] delegate];
With this:
ROSS_APP_7AppDelegate *delegate = (ROSS_APP_7AppDelegate*)[[UIApplication sharedApplication] delegate];
Does typecasting the return like this get rid of your warning?
Have you tried casting the delegate as in:
(id)[[UIApplication sharedApplication] delegate];
???
I have an App Delegate and a 3 view controllers in my project. I have a variable(a NSMutable Array) in my App Delegate which I want to access from my view controllers. So I decided to create a pointer to my App Delegate and access the variables.
Here is my code:
iSolveMathAppDelegate.h
#import <UIKit/UIKit.h>
#interface iSolveMathAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
UITabBarController *tabBarController;
NSMutableArray *tmpArray;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) NSMutableArray *tmpArray; // variable I want to access
#property (nonatomic, retain) IBOutlet UITabBarController *tabBarController;
#end
iSolveMathAppDelegate.m
#import "iSolveMathAppDelegate.h"
#implementation iSolveMathAppDelegate
#synthesize window;
#synthesize tabBarController;
#synthesize tmpArray;
...
- (void)dealloc {
[tabBarController release];
[window release];
[tmpArray release];
[super dealloc];
}
#end
The view controller class from which I want to access the tmpArray.
referenceViewController.h
#import <UIKit/UIKit.h>
#class iSolveMathAppDelegate;
#interface referenceViewController : UITableViewController {
NSMutableArray *equationTypes;
iSolveMathAppDelegate *data;
}
#property(nonatomic, retain) NSMutableArray *equationTypes;
#property(nonatomic, retain) iSolveMathAppDelegate *data;
#end
And finally referenceViewController.m
#import "referenceViewController.h"
#implementation referenceViewController
#synthesize equationTypes, data;
data = (iSolveMathAppDelegate *)[[UIApplication sharedApplication] delegate];
//says that initializer element is not constant...ERROR!
- (void)viewDidLoad {
[super viewDidLoad];
NSString *path = [[NSBundle mainBundle] pathForResource:#"equationTemplates"ofType:#"plist"];
data.tmpArray = [[NSMutableArray alloc] initWithContentsOfFile:path];
self.equationTypes = data.tmpArray;
[data.tmpArray release]; // obviously none of these work, as data is not set.
}
- (void)dealloc {
[super dealloc];
[equationTypes release];
[data release];
}
#end
So anyway at the line data = (iSolveMathAppDelegate *)[[UIApplication sharedApplication] delegate]; the compiler says that the initializer element is not constant.
I have scrouged the web for answers, and for all it seems to work...but no dice for me :( Can you please advice me on where I have gone wrong? I am using XCode 3.2 and iOS SDK 3....maybe the SDK is the problem.
Thank You
That line of code isn't in a method or function, so the compiler is treating it as the definition of a compile-time constant or static/global variable. Those need constant values for initialization.
You should put the assignment of data within a method. A good place would be -viewDidLoad:
- (void)viewDidLoad {
[super viewDidLoad];
data = (iSolveMathAppDelegate *)[[UIApplication sharedApplication] delegate];
...
}
I figured out the struct and union problem. All I had to do was change #class iSolveAppDelegate to #import "iSolveAppDelegate.h" in my referenceViewController.h file. Thanks Jonathan for your help!
In my application i want to use instance of pagecontrol in more then 3 views..so,i want to declare,#property and #synthesize should be in appDelegate..Please give some ideas to do this...
Thanks,
Mano
I never used pagecontrol, but in principle, your code would look like:
in YourAppDelegate .h
#interface YourAppDelegate : NSObject <UIApplicationDelegate> {
...
UIPageControl *pageControl;
...
}
#property (nonatomic, retain) IBOutlet ScrollingViewController *viewController;
YourAppDelegate.m:
- (void)applicationDidFinishLaunching:(UIApplication *)application {
pageControl = [[UIPageControl alloc] init]; // or whatever is needed to set up pagecontrol
}
in one of your views:
YourAppDelegate *appDelegate = (YourAppDelegate *)[[UIApplication sharedApplication] delegate];
//and then access the variable by appDelegate.variable