iOS Switch views problem

dogwong · May 19, 2010

I follow this viedo (http://www.youtube.com/watch?v=zu31fCIwt1E) and make a simular apps
but it throw a error:
"expected expression before 'ThirdViewController'"
on the line
"[self presentModalViewController:ThirdViewController animated:YES];"

I don't know what it mean....
is it because the simulator version? (i use 3 but the video use 2)
and how to switch view if this way is wrong

Please help....
and sorry for my bad English
thanks

TiberiusXavier · May 19, 2010

Can you post your code?

dejo · May 19, 2010

dogwong said:
Code:

[self presentModalViewController:ThirdViewController animated:YES];

Remember that Objective-C is case-sensitive and that ThirdViewController is a class name not an instance variable name.

dogwong · May 19, 2010

(project name is SWF)

here is the code:

SWFAppDelegate.h

Code:

#import <UIKit/UIKit.h>

@class SWFViewController;

@interface SWFAppDelegate : NSObject <UIApplicationDelegate> {
    UIWindow *window;
    SWFViewController *viewController;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet SWFViewController *viewController;

@end

SWFAppDelegate.m

Code:

#import "SWFAppDelegate.h"
#import "SWFViewController.h"

@implementation SWFAppDelegate

@synthesize window;
@synthesize viewController;


- (void)applicationDidFinishLaunching:(UIApplication *)application {    
    
    // Override point for customization after app launch    
    [window addSubview:viewController.view];
    [window makeKeyAndVisible];
}


- (void)dealloc {
    [viewController release];
    [window release];
    [super dealloc];
}


@end

SWFViewController.h

Code:

#import <UIKit/UIKit.h>
#import "SecondViewController.h"

@interface SWFViewController : UIViewController {
	IBOutlet UIButton *about;
	IBOutlet SecondViewController *SecondViewController;
}

- (IBAction)showAbout;

@end

SWFViewController.m

Code:

#import "SWFViewController.h"


@implementation SWFViewController



/*
// The designated initializer. Override to perform setup that is required before the view is loaded.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        // Custom initialization
    }
    return self;
}
*/

/*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/


/*
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];
}
*/



// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationLandscapeRight);
}


- (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.
}

- (void)viewDidUnload {
	// Release any retained subviews of the main view.
	// e.g. self.myOutlet = nil;
}


- (void)dealloc {
    [super dealloc];
}

- (IBAction)showAbout {
	[COLOR="DarkOrange"][self presentModalViewController:SecondViewController animated:YES];[/COLOR]
// this line have error
}

@end

SecondViewController.h

Code:

#import <UIKit/UIKit.h>
#import "ThirdViewController.h"


@interface SecondViewController : UIViewController {
	
	IBOutlet ThirdViewController *ThirdViewController;
	
}

- (IBAction)gotoThirdView;

- (IBAction)gotoBack;

@end

SecondViewController.h

Code:

#import <UIKit/UIKit.h>
#import "ThirdViewController.h"


@interface SecondViewController : UIViewController {
	
	IBOutlet ThirdViewController *ThirdViewController;
	
}

- (IBAction)gotoThirdView;

- (IBAction)gotoBack;

@end

SecondViewController.m

Code:

#import "SecondViewController.h"


@implementation SecondViewController

- (IBAction)gotoThirdView{
	[self presentModalViewController:ThirdViewController animated:YES];
}

- (IBAction)goBack{
	[self dismissModalViewControllerAnimated:YES];
}
/*
 // The designated initializer.  Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        // Custom initialization
    }
    return self;
}
*/

/*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/

/*
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];
}
*/

/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/

- (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.
}

- (void)viewDidUnload {
	// Release any retained subviews of the main view.
	// e.g. self.myOutlet = nil;
}


- (void)dealloc {
    [super dealloc];
}


[COLOR="darkorange"]@end[/COLOR] warning: incomplete implementation of class 'SecondViewController'

ThirdViewController.h

Code:

#import <UIKit/UIKit.h>


@interface ThirdViewController : UIViewController {
	
	
	
}

- (IBAction)goBack;

@end

ThirdViewController.m

Code:

#import "ThirdViewController.h"


@implementation ThirdViewController

- (IBAction)goBack{
	[self dismissModalViewControllerAnimated:YES];
}

/*
 // The designated initializer.  Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        // Custom initialization
    }
    return self;
}
*/

/*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/

/*
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];
}
*/

/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/

- (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.
}

- (void)viewDidUnload {
	// Release any retained subviews of the main view.
	// e.g. self.myOutlet = nil;
}


- (void)dealloc {
    [super dealloc];
}


@end

SWFViewController.xib

a button: title: about
connection: Touch up inside - file's owner showAbout

SecondView.xib

a label, text: Second
a button, title: go to third
connection: Touch up inside - file's owner gotoThirdView
a button, title: back
connection: Touch up inside - file's owner gotoBack

ThirdView.xib
a label, text: Third
a button, title: Back
connection: Touch up inside - file's owner gotoBack

Thanks

Svinja · May 20, 2010

Hi,
as dejo said...this part of the code is wrong:

Code:

- (IBAction)gotoThirdView
{
	[self presentModalViewController:ThirdViewController animated:YES];
}

ThirdViewController is a class, you must use instance of that class in order for this to work...for example

Code:

- (IBAction)gotoThirdView
{
        ThirdViewController *thirdViewController=[[ThirdViewController alloc] init];
	[self presentModalViewController:thirdViewController animated:YES];
        [thirdViewController release];
}

notice the capital letters...

dogwong · May 20, 2010

Svinja said:
Hi,
as dejo said...this part of the code is wrong:

Code:

- (IBAction)gotoThirdView { [self presentModalViewController:ThirdViewController animated:YES]; }

ThirdViewController is a class, you must use instance of that class in order for this to work...for example

Code:

- (IBAction)gotoThirdView { ThirdViewController *thirdViewController=[[ThirdViewController alloc] init]; [self presentModalViewController:thirdViewController animated:YES]; [thirdViewController release]; }

notice the capital letters...

Build and Run succeeded.

But when i try that, it is normal if I switch between first and second view, and it crash when I switch to third view, what's wrong?
and is that any way to find what make the apps carsh?
Thanks

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iOS Switch views problem

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