Why does my pushViewController not work - ios

Question

When I hit an element in my tableView it comes up with an error. I have checked all of the connections but still cant work it out. Here is my code
#import "CGViewController.h"
#import "CGAppDelegate.h"
#import "sls.h"
#import "patientController.h"
#interface CGViewController ()
#end
#implementation CGViewController
- (void)viewDidLoad
{
[super viewDidLoad];
self.title = #"Patients";
CGAppDelegate *delegate =
(CGAppDelegate *)[[UIApplication sharedApplication] delegate];
patients = delegate.patients;
self.navigationItem.rightBarButtonItem = self.editButtonItem;
UIBarButtonItem *addButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:#selector(add:)];
self.navigationItem.leftBarButtonItem = addButtonItem;
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark UITableViewDataSource Methods
- (UITableViewCell *)tableView:(UITableView *)tv
cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tv dequeueReusableCellWithIdentifier:#"cell"];
if( nil == cell) {
cell = [[UITableViewCell alloc]
initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:#"cell"];
}
if (indexPath.row < patients.count) {
sls *thissls = [patients objectAtIndex:indexPath.row];
cell.textLabel.text = thissls.patientName;
}
else {
cell.textLabel.text = #"";
cell.textLabel.textColor = [UIColor lightGrayColor];
}
return cell;
}
-(void)setEditing:(BOOL)editing animated:(BOOL)animated {
if ( editing != self.editing) {
[super setEditing:editing animated:animated];
[self.tableView setEditing:editing animated:animated];
NSArray *indexes =
[NSArray arrayWithObject:
[NSIndexPath indexPathForRow:patients.count inSection:0]];
if ( editing == YES ) {
[self.tableView insertRowsAtIndexPaths:indexes withRowAnimation:UITableViewRowAnimationLeft];
} else {
[self.tableView deleteRowsAtIndexPaths:indexes withRowAnimation:UITableViewRowAnimationLeft];
}
}
[self.tableView reloadData];
}
-(UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath {
if (indexPath.row < patients.count ) {
return UITableViewCellEditingStyleDelete;
}
else {
return UITableViewCellEditingStyleNone;
}
}
- (NSInteger)tableView:
(UITableView *)tv numberOfRowsInSection:
(NSInteger)section {
NSInteger count = patients.count;
if (self.editing) {
count = count + 1;
}
return count;
}
-(void)tableView:(UITableView *)tv didSelectRowAtIndexPath:
(NSIndexPath *)indexPath {
CGAppDelegate *delegate =
(CGAppDelegate *)[[UIApplication sharedApplication] delegate];
patientController *patient = [[patientController alloc] init];
[delegate.navController pushViewController:patient animated: YES];
[tv deselectRowAtIndexPath:indexPath animated: YES];
}
-(void) tableView:(UITableView *)tv
commitEditingStyle:(UITableViewCellEditingStyle)editing forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editing == UITableViewCellEditingStyleDelete) {
[patients removeObjectAtIndex:indexPath.row];
[tv deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath]
withRowAnimation:UITableViewRowAnimationLeft];
}
}
#end
Any ideas on what is wrong if you know please can you help as soon as possible as i am on a deadline
Thanks in advance.
The error says Thread 1:signal SIGABRT
The error is in main.m
#import <UIKit/UIKit.h>
#import "CGAppDelegate.h"
int main(int argc, char *argv[])
{
#autoreleasepool {
return UIApplicationMain(argc, argv, nil, NSStringFromClass([CGAppDelegate class]));
}
}
it says that the error is here
patientController *patient = [[patientController alloc] init];
here is my patientController.h file
#import <UIKit/UIKit.h>
#interface patientController : UIViewController {
NSIndexPath *index;
IBOutlet UIImageView * pictureView;
IBOutlet UILabel * descriptionView1;
IBOutlet UILabel * descriptionView2;
IBOutlet UILabel * descriptionView3;
}
- (id)initwithIndexPath:(NSIndexPath *)indexPath;
#end
and my .m file
#import "patientController.h"
#import "CGAppDelegate.h"
#import "sls.h"
#interface patientController ()
#end
#implementation patientController
- (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.
CGAppDelegate *delegate =
(CGAppDelegate *)[[UIApplication sharedApplication] delegate];
sls *thissls = [delegate.patients objectAtIndex:index.row];
self.title = thissls.patientName;
self->descriptionView1.text = thissls.patientName;
self->descriptionView2.text = thissls.surnameName;
self->descriptionView3.text = thissls.dateOfBirth;
self->pictureView.image = thissls.patientImage;
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (id)initwithIndexPath:(NSIndexPath *)indexPath {
if ( (self == [super init]) ) {
index = indexPath;
}
return self;
}
#end
Please can anyone at all help

Answer 1

Use:
[self.navigationController pushViewController:patient animated: YES];

Answer 2

If you are currently in a navigationController (which you have to in order to push a new ViewController), then you can push your new controller by just calling these lines
-(void)tableView:(UITableView *)tv didSelectRowAtIndexPath:
(NSIndexPath *)indexPath {
patientController *patient = [[patientController alloc] init];
[self.navigationController pushViewController:patient animated: YES];
}

Answer 3

Use
[self.navController pushViewController:patient animated: YES];
Every viewcontroller has its navigation controller reference in itself,no need to call the application delegate to invoke it[The navigation controller Must be initialised and all the viewcontrollers must be pushed into the navigation stack until this one to make it work]
So use this to setup the navigation controller in the appdelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
//Note : this is an example set like this with your viewcontroller instance
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
self.viewController = [[ViewController alloc] initWithNibName:#"ViewController_iPhone" bundle:nil];
} else {
self.viewController = [[ViewController alloc] initWithNibName:#"ViewController_iPad" bundle:nil];
}
self.window.rootViewController = [[UINavigationController alloc] initWithRootViewController:self.viewController];
[self.window makeKeyAndVisible];
return YES;
}

Answer 4

To check where your exception is raised, in Xcode, in the breakpoints navigation tab click on the plus button in the bottom-left corner and add an Exceptions Breakpoint. Then run the app from Xcode. The next time an exception is raised, as in your case, the execution of your app will stop and Xcode will point at the line of code where the exception is raised.
Anyway, to make you understand how navigationControllers work:
UINavigationController is a UIViewController that controls a stack of other UIViewController instances. This other view controllers are said to be in the 'navigation stack'. The top item in the navigation stack is the view controller whose view you see at a given time onto the screen. You can push (present) or pop (dismiss) a view controller on/from the navigation stack.
A UINavigationController is initialized with a 'rootViewController' which is going to be it's first view controller onto the stack and therefore the first you see when you add the navigationController onto the screen (e.g. by setting it as the appDelegate window's rootViewController). Each UIViewController on the navigation stack references it's navigationController through the property 'navigationController'.
At any given point, you can use the UINavigationController methods pushViewController:animated: and popViewControllerAnimated: or popToViewController:animated: or popToRootViewControllerAnimated: to add or remove viewControllers from the navigationStack. To see the results of this methods, of course, you should have the navigationController on screen.
For more informations refer to the UINavigationController Class Reference.