iPhone Objective C - can't display new view - iphone

Question

I'm finding it difficult to get started in Objective-C.
I'm executing the following code when a button is clicked:
NSLog(#"hi");
MainMenuDriver *mainMenuDriver= [[MainMenuDriver alloc] initWithNibName:nil bundle:nil];
[[self navigationController]pushViewController:mainMenuDriver animated:YES];
I can see "hi" in the console when I hit the button, it's just that the view should change to MainMenuDriver. But nothing happens!
Please help!
As per request for more code:
MainMenuDriver.h:
#import <UIKit/UIKit.h>
#import <CoreLocation/CoreLocation.h>
#interface MainMenuDriver : UIViewController <UINavigationControllerDelegate,CLLocationManagerDelegate>{
IBOutlet UIButton *photos;
IBOutlet UIButton *profile;
IBOutlet UISwitch *onOffline;
IBOutlet UILabel *label1;
NSTimer *uploadGPS_timer;
CLLocationManager *lm;
NSString *lat;
NSString *lng;
}
#property(nonatomic,retain) UIButton *photos;
#property(nonatomic,retain) UIButton *profile;
#property(nonatomic,retain) UISwitch *onOffline;
#property(nonatomic,retain) UILabel *label1;
#property (nonatomic,retain) NSTimer *uploadGPS_timer;
#property(nonatomic,retain) NSString *lat,*lng;
-(IBAction)showMessages:(id)sender;
-(IBAction)showFriends:(id)sender;
-(IBAction)showPhotos:(id)sender;
-(IBAction)showProfile:(id)sender;
-(IBAction)switchSwitched:(id)sender;
-(void)uploadGPS_tick:(NSTimer*)timer;
#end
MainMenuDriver.m
#import "MainMenuDriver.h"
#import "ASIFormDataRequest.h"
#import "JoeMaxiViewController.h"
#import "Photos.h"
#import "Profile.h"
#implementation MainMenuDriver
#synthesize messages,profile,photos,friends,label1;
#synthesize onOffline;
#synthesize uploadGPS_timer;
#synthesize lat,lng;
-(IBAction)showPhotos:(id)sender{
[self.navigationItem setBackBarButtonItem:[[UIBarButtonItem alloc] initWithTitle:#"Back" style:UIBarButtonItemStylePlain target:nil action:nil]];
Photos *x= [[Photos alloc] initWithNibName:nil bundle:nil];
[[self navigationController]pushViewController:x animated:YES];
}
-(IBAction)showProfile:(id)sender{
[self.navigationItem setBackBarButtonItem:[[UIBarButtonItem alloc] initWithTitle:#"Back" style:UIBarButtonItemStylePlain target:nil action:nil]];
Profile *x= [[Profile alloc] initWithNibName:nil bundle:nil];
[[self navigationController]pushViewController:x animated:YES];
}
-(void)logout:(id)sender{
if([uploadGPS_timer isValid]){
[uploadGPS_timer invalidate];
}
[lm release];
//[uploadGPS_timer release];
[self.navigationController popViewControllerAnimated:NO];
/*NSString *urlStr=[[NSString alloc] initWithFormat:#"http://www.prestocab.com/driver/ajax/logout.php"];
NSURL *url=[NSURL URLWithString:urlStr];
__block ASIFormDataRequest *request=[[ASIFormDataRequest alloc ]initWithURL:url];
[request setDelegate:self];
[request setCompletionBlock:^{
NSString *response=[request responseString];
NSLog(#"%#",response);
}];
[request setFailedBlock:^{
}];
[request startAsynchronous];*/
}
-(IBAction)switchSwitched:(id)sender{
if(onOffline.on){
[label1 setText:#"For Hire"];
[label1 setTextColor:[UIColor colorWithRed:0.0 green:0.8 blue:0.0 alpha:1.0]];
uploadGPS_timer=[NSTimer scheduledTimerWithTimeInterval:10.0 target:self selector:#selector(uploadGPS_tick:) userInfo:nil repeats:YES];
[self uploadGPS_tick:nil];
}else{
[label1 setText:#"Engaged"];
[label1 setTextColor:[UIColor colorWithRed:0.8 green:0.0 blue:0.0 alpha:1.0]];
if([uploadGPS_timer isValid]){
[uploadGPS_timer invalidate];
}
}
}
-(void)uploadGPS_tick:(NSTimer*)timer{
if(!lat || !lng){
//do nothing
}else{
NSString *urlStr=[[NSString alloc] initWithFormat:#"http://www.prestocab.com/driver/ajax/updateCoords.php"];
NSURL *url=[NSURL URLWithString:urlStr];
__block ASIFormDataRequest *request=[[ASIFormDataRequest alloc ]initWithURL:url];
[request setPostValue:lat forKey:#"lat"];
[request setPostValue:lng forKey:#"lng"];
NSLog(#"EOH: %#",lat);
[request setDelegate:self];
[request setCompletionBlock:^{
NSString *response=[request responseString];
NSLog(#"%#",response);
//do nothing
}];
[request setFailedBlock:^{
//NSError *error =[request error];
//do nothing
}];
[request startAsynchronous];
}
}
-(void)locationManager:(CLLocationManager*) manager didUpdateToLocation:(CLLocation *) newLocation fromLocation:(CLLocation*) oldLocation{
lat=[[NSString alloc]initWithFormat:#"%g",newLocation.coordinate.latitude];
lng=[[NSString alloc]initWithFormat:#"%g",newLocation.coordinate.longitude];
NSLog(#"%#,%#",lat,lng);
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)didReceiveMemoryWarning
{
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
self.navigationItem.title=#"PrestoCab";
UIBarButtonItem *anotherButton = [[UIBarButtonItem alloc] initWithTitle:#"Logout" style:UIBarButtonItemStylePlain target:self action:#selector(logout:)];
self.navigationItem.rightBarButtonItem = anotherButton;
[anotherButton release];
//GPS
lm=[[CLLocationManager alloc] init];
if([CLLocationManager locationServicesEnabled]){
lm.delegate=self;
lm.desiredAccuracy=kCLLocationAccuracyBest;
lm.distanceFilter=30.0f;
[lm startUpdatingLocation];
}
//[self check4messages_tick:nil]; //want to start immediately, not in 10/40 seconds' time
[self uploadGPS_tick:nil];
//check4messages_timer=[NSTimer scheduledTimerWithTimeInterval:40.0 target:self selector:#selector(check4messages_tick:) userInfo:nil repeats:YES];
uploadGPS_timer=[NSTimer scheduledTimerWithTimeInterval:10.0 target:self selector:#selector(uploadGPS_tick:) userInfo:nil repeats:YES];
[super viewDidLoad];
}
- (void)viewDidUnload
{
[super viewDidUnload];
if([uploadGPS_timer isValid]){
[uploadGPS_timer invalidate];
}
}
-(void)dealloc{
[super dealloc];
[uploadGPS_timer release];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
#end
Also, here is
MyClassViewController.h:
#import <UIKit/UIKit.h>
#interface MyClassViewController : UINavigationController{
IBOutlet UIButton *passenger;
IBOutlet UIButton *driver;
}
#property (nonatomic,retain) UIButton *passenger;
#property (nonatomic,retain) UIButton *driver;
-(IBAction) passengerClicked:(id)sender;
-(IBAction) driverClicked:(id)sender;
#end
and MyClassViewController.m:
#import "MyClassViewController.h"
#import "MainMenuDriver.h"
#implementation MyClassViewController
#synthesize passenger;
#synthesize driver;
-(IBAction)passengerClicked:(id)sender{
NSLog(#"passenger");
}
-(IBAction)driverClicked:(id)sender{
NSLog(#"driver");
MainMenuDriver *mainMenuDriver= [[MainMenuDriver alloc] initWithNibName:nil bundle:nil];
[[self navigationController]pushViewController:mainMenuDriver animated:YES];
}
- (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.
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
}
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
}
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
}
- (void)viewDidDisappear:(BOOL)animated
{
[super viewDidDisappear:animated];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}
#end

Answer 1

I can see a couple of things:
Your nib file's name is different from the name of your class. If you put nil, the UIViewController will try to load a nib file with the UIViewController's name. Your UIViewController can be MainMenuDriver but your nib file name can be MainMenuDriverNibFileName.nib
[self navigationController] is nil.
For this, do the following:
NSLog(#"hi");
if([self navigationController]){
MainMenuDriver *mainMenuDriver= [[MainMenuDriver alloc] initWithNibName:nil bundle:nil];
[[self navigationController]pushViewController:mainMenuDriver animated:YES];
}
else{
NSLog(#"Houston we have a problem");
}
Update 1:
So, its nil, what you can do is the following:
Quick and Dirty:
[self presentViewController:mainMenuDriver animated:YES];
Instead of UIViewController switch to a UINavigationController.