i am doing an apps which i need to call nsobject class in a view controller class, i try a couple method but its not working either i get a sigabrt error or the apps crash.
please help me.
I'm lost for days now.
any one have a sample code for calling nsobject from view controller?
thanks in advance for you kind help.
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController
-(IBAction)firstButton;
#end
#import <UIKit/UIKit.h>
#interface TutoAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
UINavigationController *navigationController;
UIButton *firstButton;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet UINavigationController *navigationController;
#property (nonatomic, retain) IBOutlet UIButton *firstButton;
#end
Please post some code where we can provide the correct solution. Even I don't get problem exactly but if you want to call class object then do the following.
-(void)buttoevent:(id)sender
{
nsobjectclass *obj = [[nsobjectclass alloc]init];
//if you want to call any method of that class then do the following.
[obj methodname];
}
First of all check if you have imported the class before using it
Related
I'm trying to do something like this: http://www.pushplay.net/2009/05/framework-for-having-multiple-views-in-an-iphone-app/
So far I've got this structure: appDelegate -> rootViewController -> welcomeViewController
I've a method (doSomething) in my delegate, which is called by an IBAction in welcomeViewController. It works, I can do an NSlog in doSomething and it shows the method is being called within the delegate.
The problem is when I run a command like [rootViewController loadNewView] in my doSomething method (in the delegate), it does nothing. It doesn't error, it just does nothing.
I've been reading and seen protocols and notifications are suggested, but I'd like to know why this method using the delegate doesn't work and if there is any way to fix it.
SurveyClientAppDelegate.h
#interface SurveyClientAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
RootViewController *rootViewController;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet RootViewController *rootViewController;
-(void)doSomething;
#end
SurveyClientAppDelegate.m
- (void)doSomething {
NSLog(#"Attempt: rootViewController loadLocationList");
[rootViewController loadLocationList];
}
RootViewController.h
#interface RootViewController : UIViewController {
WelcomeViewController *welcomeView;
}
#property (nonatomic, retain) WelcomeViewController *welcomeView;
#property (nonatomic, retain) SurveyListViewController *surveyList;
-(void)loadLocationList;
RootViewController.m
- (void)loadLocationList
{
NSLog(#"RootViewController: loadLocationList");
}
WelcomeViewController.h
#interface WelcomeViewController : UIViewController
-(IBAction)viewList:(id)sender;
-(void)loadLocationList;
WelcomeViewController.m
- (void)viewList:(id)sender
{
SurveyClientAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
[appDelegate doSomething];
}
Are you keeping a reference to rootViewContoller in your welcomeViewController? It's possible (and likely) that rootViewController will be released before you can call methods on it.
This is a good time to use delegates. You mention calling a method "in the delegate" but without seeing any of your code it's difficult to tell if you're using it correctly or not.
I want to call a function in a viewController from my appDelegate but with the following code, it doesn't get called. What am I doing wrong?
AppDelegate.h:
#import <UIKit/UIKit.h>
#import "DetailsToTransfer.h"
#class AccountDetailTransferViewController;
#interface AccountDetailTransferAppDelegate : NSObject <UIApplicationDelegate> {
DetailsToTransfer *objDetailsToTransfer;
}
#property (nonatomic, retain) DetailsToTransfer *objDetailsToTransfer;
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet AccountDetailTransferViewController *viewController;
-(void)sendToTransferScreen:(NSArray *)detailsArray;
#end
AppDelegate.m:
....
-(void)sendToTransferScreen:(NSArray *)detailsArray {
[objDetailsToTransfer setLabels:detailsArray];
objDetailsToTransfer = [[DetailsToTransfer alloc]initWithNibName:#"DetailsToTransfer" bundle:nil];
[self.window addSubview:objDetailsToTransfer.view];
}
DetailsToTransfer.h:
#import <UIKit/UIKit.h>
#interface DetailsToTransfer : UIViewController {
NSArray *accountDetailsArray;
UILabel *nameLabel;
UILabel *accountLabel;
IBOutlet UIButton *btnTransfer;
IBOutlet UIButton *btnBack;
}
#property (nonatomic, retain) NSArray *accountDetailsArray;
#property (nonatomic, retain) IBOutlet UILabel *nameLabel;
#property (nonatomic, retain) IBOutlet UILabel *accountLabel;
-(IBAction)sendDetails;
-(IBAction)goBack;
-(void)setLabels:(NSArray *)array;
#end
DetailsToTransfer.m
....
-(void)setLabels:(NSArray *)array {
NSLog(#"Setting Labels");
self.nameLabel.text = [array objectAtIndex:0];
self.accountLabel.text = [array objectAtIndex:1];
}
....
I would like to add that all the properties have been synthesized and that I'm calling the method in the appDelegate properly (i checked using NSLogs)
In AppDelegate.m:
Looks as if you are calling a method on your object before the object has been created. Until you have alloc / init your object, there will be no labels to set text.
Try changing your method to this:
-(void)sendToTransferScreen:(NSArray *)detailsArray {
if (!objDetailsToTransfer) {
objDetailsToTransfer = [[DetailsToTransfer alloc]initWithNibName:#"DetailsToTransfer" bundle:nil];
[objDetailsToTransfer setLabels:detailsArray];
[self.window addSubview:objDetailsToTransfer.view];
}
}
The problem might be that you are trying to set the values on a object that hasn't been created yet. I also provided an if statement to prevent the object from being created multiple times.
In the Apple sample code, the AppDelegate contains window and navigationController as instance variable. (http://developer.apple.com/library/ios/#samplecode/TableViewSuite/Listings/1_SimpleTableView_Classes_SimpleTableViewAppDelegate_h.html%23//apple_ref/doc/uid/DTS40007318-1_SimpleTableView_Classes_SimpleTableViewAppDelegate_h-DontLinkElementID_5)
#interface SimpleTableViewAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
UINavigationController *navigationController;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) UINavigationController *navigationController;
The code generated by XCode4 is only as simple as
#interface SimpleTableViewAppDelegate : NSObject <UIApplicationDelegate> {
}
Why the two instances variables can be missed?
Why only the *window need to be declared as IBOutlet, but not *navigationController?
Thanks.
The LLVM compiler used by Xcode 4 can automatically generate instance variables for synthesized properties. When a property is declared and synthesized, the compiler will automatically generate the corresponding ivar. It's a great feature as it not only saves typing but also makes the external interface of a class cleaner.
I am trying to add a record to the database using core data. The appDelegate has the managed object model, context, and store coordinator setup in it. When the app is launched and I query the fetchResultsController method in one of my views the database is created matching the scheme with the correct table names and columns in it. However the problem comes when I try to add a record to the table.
The BurpListNavController.h file has the following contents (I am just learning):
#import <UIKit/UIKit.h>
#class BurpRecordController;
#interface BurpListNavController : UINavigationController <NSFetchedResultsControllerDelegate> {
BurpRecordController *burpRecordController;
NSFetchedResultsController *fetchedResultsController;
NSManagedObjectContext *managedObjectContext;
}
#property (nonatomic, retain) IBOutlet BurpRecordController *burpRecordController;
#property (nonatomic, retain) NSFetchedResultsController *fetchedResultsController;
#property (nonatomic, retain) NSManagedObjectContext *managedObjectContext;
- (void)saveBurpLocal:(id)sender;
#end
I then have a view that records the burp, yes another one of the thousands of burp applications. haha. The following code is as follows:
#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
#import <CoreAudio/CoreAudioTypes.h>
#class BurpLocal;
#class BurpListNavController;
#interface BurpRecordController : UIViewController <AVAudioRecorderDelegate, UIActionSheetDelegate> {
/*** Outlets to talk to the view ***/
IBOutlet UITextField *burpName;
IBOutlet UIButton *_recordButton;
/*** Standard Variables ***/
NSURL *recordedTmpFile;
//AVAudioRecorder *recorder;
NSError *error;
BurpLocal *burpLocal;
BurpListNavController *burpListNavController;
}
/*** Properties ***/
#property (nonatomic, retain) IBOutlet UITextField *burpName;
#property (nonatomic, retain) IBOutlet UIButton *recordButton;
#property (nonatomic, assign) IBOutlet BurpListNavController *burpListNavController;
#property(nonatomic, retain) BurpLocal *burpLocal;
/*** Method ***/
-(IBAction)saveRecording:(id)sender;
-(void)applicationWillTerminate:(NSNotification *)notification;
#end
When the end-user pushes the "save" button it calls the "saveRecording" method which I can step into and is great. Then I try to call the following line of code within the "saveRecording" method: [burpListNavController saveBurpLocal:sender]; thinking this will call the "saveBurpLocal" method in the nav controller and it just steps over it, does not stop at the break point in the nav controller method and then just goes to the end of the current "saveRecording" function. Does not write a record to the database or anything.
Please help! This is driving me crazy.
It's difficult to tell without more code; but it sounds like burpListNavController has not been set. When you step through the saveRecording: method, is the value of burpListNavController 0x0? If it is then you have forgotten to set that iVar somewhere.
If you have come from another language this might sound a little strange, as usually calling a method on a null pointer you cause you to crash. This isn't the case in Objective-C though, it is perfectly legal to send a message to nil; but don't expect anything to actually happen.
So we have recently started developing applications for the iPad for our company. Unfortunately none of us here have ever done any iPhone/iPad development so we are just kind of learning on the fly and winging it. Basically our problem is happening when we try to push a view onto the screen when a table row is clicked. Neither of us can figure out why it's not doing it because the code looks 100% correct by anything we can tell. Here is what the didRowSelectedAtIndex: method looks like:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// Navigation logic -- create and push a new view controller
if(pdvController == nil)
pdvController = [[PersonDetailViewController alloc] initWithNibName:#"PersonDetailView" bundle:[NSBundle mainBundle]];
Person *aPerson = [appDelegate.people objectAtIndex:indexPath.row];
pdvController.aPerson = aPerson;
[self.appDelegate.navigationController pushViewController:pdvController animated:YES];
}
and here is the header for the toolbarSearchViewController:
#import <UIKit/UIKit.h>
#import "RecentSearchesController.h"
#import "PersonDetailViewController.h"
#class ToolbarSearchAppDelegate, PersonDetailViewController;
#interface ToolbarSearchViewController : UIViewController <UISearchBarDelegate, UIPopoverControllerDelegate, RecentSearchesDelegate> {
ToolbarSearchAppDelegate *appDelegate;
UIToolbar *toolbar;
UISearchBar *searchBar;
UITableView *resultsTable;
PersonDetailViewController *pdvController;
RecentSearchesController *recentSearchesController;
UITableViewController *resultsTableController;
UIPopoverController *recentSearchesPopoverController;
}
#property (nonatomic, retain) IBOutlet UIToolbar *toolbar;
#property (nonatomic, retain) UISearchBar *searchBar;
#property (nonatomic, retain) IBOutlet UITableView *resultsTable;
#property (nonatomic, retain) ToolbarSearchAppDelegate *appDelegate;
#property (nonatomic, retain) PersonDetailViewController *pdvController;
#property (nonatomic, retain) UITableViewController *resultsTableController;
#property (nonatomic, retain) RecentSearchesController *recentSearchesController;
#property (nonatomic, retain) UIPopoverController *recentSearchesPopoverController;
#end
and the ToolbarSearchAppDelegate header:
#import <UIKit/UIKit.h>
#class ToolbarSearchViewController;
#interface ToolbarSearchAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
ToolbarSearchViewController *viewController;
UINavigationController *navigationController;
NSMutableArray *people;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet ToolbarSearchViewController *viewController;
#property (nonatomic, retain) IBOutlet UINavigationController *navigationController;
#property (nonatomic, retain) NSMutableArray *people;
#end
and finally the personDetailController.h:
#import <UIKit/UIKit.h>
#class Person;
#interface PersonDetailViewController : UIViewController {
IBOutlet UITableView *tableView;
Person *aPerson;
}
#property (nonatomic, retain) Person *aPerson;
#property (nonatomic, retain) UITableView *tableView;
#end
We are getting pretty annoyed because neither of us can figure out why it's not loading and any help or insight you guys could provide would be amazing. I wasn't sure what you may need to see, so if you need anything more specific, let me know and I will post it. Thanks!
ps. I am not sure how the code tags are going to handle all of Obj-c's quirky syntax, so if you see syntax errors, just ignore them. Assume that it is syntactically correct and will compile and run...
This line looks a little odd:
[self.appDelegate.navigationController pushViewController:pdvController animated:YES];
try and make it
[self.navigationController pushViewController:pdvController animated:YES];
edit summing op, the problem is that you don't have a navigation controller, so you can't push a view controller like that. What you can do, is pushing a view controller modally, using
[self presentModalViewController:pdvController animated:YES];