Im getting only this failure after having built the project.
Im using the XCode 4.6.3
class.m
#import "Car.h"
//constructor
-(id)init //<----- ***MISSING CONTEXT FOR METHOD DECLARATION***
{
self = [super init];
if(self){
self.brand = #"";
self.model = #"";
self.vin = 0;
}
return self;
class.h contains no error.
#import <Foundation/Foundation.h>
#interface Car : NSObject
{
NSString *brand, *model;
NSNumber *vin;
}
//set
-(void) setBrand:(NSString *) newBrand;
-(void) setModel:(NSString *) newModel;
-(void) setVIN:(NSNumber *) newVIN;
//get
-(NSString *) getBrand;
-(NSString *) getModel;
-(NSNumber *) getVIN;
//methods
-(void) accelerateTo100;
-(void) fuelConsuming;
-(void) hardStop;
#end
Can you help me with this. Thanks alot.
Answer is what #CodaFi explained. Try this
#import "Car.h"
#implementation Car
-(id)init
{
self = [super init];
if(self){
[self setBrand : #""];
[self setMode1 : #""];
[self setVIN : #""];
}
return self;
}
#end
Implementations of methods related to the Car class are always wrapped in #implementation Car and terminated with an #end. You're declaring and implementing methods without telling the compiler which class they belong to.
Check that you don't have an #import "..." within the #implementation section.
Related
I have written a method formatSearchString for a class and am trying to call it on a line before it is implemented (shouldn't matter?). I get this error:
Error: Semantic Issue
Use of undeclared identifier 'formatSearchString'
I am using XCode 4.6.2
The interface file FHViewController.h:
#import <Foundation/Foundation.h>
#interface FHViewController : UITableViewController
<UITableViewDataSource, UITableViewDelegate, NSURLConnectionDataDelegate>
#property(strong, nonatomic) NSString *searchTerm;
- (NSString *)formatSearchString:(NSString *)userEntry;
#end
The implementation file FHViewController.m:
#import "FHViewController.h"
#interface FHViewController()
- (NSString *)formatSearchString:(NSString *)userEntry;
#end
#implementation FHViewController
#synthesize searchTerm;
-(void)viewDidLoad
{
[super viewDidLoad];
NSString *formatted = [formatSearchString userEntry:searchTerm];
}
- (NSString *)formatSearchString:(NSString *)userEntry
{
NSLog(#"User Entry: %#", userEntry);
return #"Dummy string for now";
}
#end
NSString *formatted = [formatSearchString userEntry:searchTerm];
That line is wrong. Note the difference :
NSString *formatted = [self formatSearchString:searchTerm];
You are using formatSearchString as a variable name, not a method name, you need to call formatSearchString on an object:
NSString *formattedString = [self formatSearchString:mySearchString];
The syntax for a method call in Objective C is [receiver method: param1 ...]. So you need to change your code to:
-(void)viewDidLoad
{
[super viewDidLoad];
NSString *formatted = [self formatSearchString: searchTerm];
}
I have an interface:
#import <Foundation/Foundation.h>
#interface Picture : NSObject;
#property (readonly) NSString *filepath;
- (UIImage *)image;
#end
and implementation:
#import "Picture.h"
#define kFilepath #"filepath"
#interface Picture () <NSCoding> {
NSString *filepath;
}
#end
#implementation Picture
#synthesize filepath;
- (id)initWithCoder:(NSCoder *)aDecoder {
self = [super initWithCoder:aDecoder];
return self;
}
- (void)encodeWithCoder:(NSCoder *)aCoder {
[aCoder encodeObject:filepath forKey:kFilepath];
}
- (UIImage *)image {
return [UIImage imageWithContentsOfFile:filepath];
}
#end
I get error: ARC issue - No visible #interface for 'NSObject' declares the selector' initWithCoder:'
Is there something different about NSCoding when using ARC?
Thanks
There's nothing different between ARC and manual reference counting. NSObject doesn't conform to NSCoding and therefore doesn't supply -initWithCoder: or -encodeWithCoder:. Just don't call through to the superclass implementations of those methods.
- (id)initWithCoder: (NSCoder *)aCoder {
self = [super init];
if (self) {
[aCoder decodeObject: filepath forKey: kFilepath];
}
return self;
}
I have created a singleton for my MusicBackground. And I receive a line code of imcomplete implementation of this line #implementation MyBgMusic. Can anyone tell me why ? Below is the code:
#import "MyBgMusic.h"
static MyBgMusic *sharedMyManager = nil;
#implementation MyBgMusic
#synthesize player,playBgMusic;
#pragma mark -
#pragma mark Singleton Methods
+ (MyBgMusic*)sharedInstance {
static MyBgMusic *_sharedInstance;
if(!_sharedInstance) {
static dispatch_once_t oncePredicate;
dispatch_once(&oncePredicate, ^{
_sharedInstance = [[super allocWithZone:nil] init];
});
}
return _sharedInstance;
}
+ (id)allocWithZone:(NSZone *)zone {
return [self sharedInstance];
}
- (id)copyWithZone:(NSZone *)zone {
return self;
}
#if (!__has_feature(objc_arc))
- (id)retain {
return self;
}
- (unsigned)retainCount {
return UINT_MAX; //denotes an object that cannot be released
}
- (id)autorelease {
return self;
}
- (void)dealloc
{
[MyBgMusic release];
[playBgMusic release];
[player release];
[super dealloc];
}
#endif
#pragma mark -
#pragma mark Custom Methods
- (void)viewDidLoad
{
NSString *path = [[NSBundle mainBundle] pathForResource:#"music" ofType:#"mp3"];
self.player=[[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:path] error:NULL];
player.delegate = self;
[player play];
player.numberOfLoops = -1;
[super viewDidLoad];
}
#end
For the M file, below is the code:
#import <Foundation/Foundation.h>
#import <AVFoundation/AVAudioPlayer.h>
#interface MyBgMusic : UIViewController <AVAudioPlayerDelegate> {
AVAudioPlayer *player;
UIButton *playBgMusic;
}
#property (nonatomic, retain) IBOutlet AVAudioPlayer *player;
#property (nonatomic, retain) IBOutlet UIButton *playBgMusic;
+ (id)sharedManager;
-(IBAction) toggleMusic;
#end
And how do I reference to my toggle button: Below is the code :
- (IBAction)toggleMusic {
if ([self.player isPlaying] == YES) {
[self.player stop];
} else {
[self.player play];
}
self.playBgMusic.enabled = YES;
}
It means that your MyBgMusic class isn't doing everything it promised to do in its header file, which includes being a UIViewController and implementing the AVAudioPlayerDelegate protocol. I'm not familiar with exactly what the AVAudioPlayerDelegate is, but it's quite possible that your class doesn't implement all of the required methods.
Also, you're declaring methods +(id)sharedManager and -(IBAction)toggleMusic, but I don't see them anywhere in the implementation file. That would be a case of promising something in the header and not implementing it in the class.
It would help if you posted the actual error message.
That error means your #implementation section does not contain everything described in the #interface section.
I can see two problems.
First you need to place this code:
- (IBAction)toggleMusic {
...
}
Somewhere in between #implementation and #end.
And you also need to rename the line + (MyBgMusic*)sharedInstance to + (id)sharedManager.
EDIT:
To access the toggle music method elsewhere in your code, you would do:
[[MyBgMusic sharedManager] toggleMusic];
Your +(id)sharedManagerimplementation is called +(id)sharedInstance. Just guessing, but it seems they are supposed to do the same.
This is a sample from book "Cocoa Programming For Mac Os X 3rd(HD)" chapter 7 "Key-Value Coding. Key-Vaule Observing
Here is the code:
Person.h:
#import <Foundation/Foundation.h>
#interface Person : NSObject {
NSString *personName;
float expectedRaise;
}
#property (readwrite, copy) NSString *personName;
#property (readwrite) float expectedRaise;
#end
Person.mm:
#import "Person.h"
#implementation Person
#synthesize expectedRaise;
#synthesize personName;
- (id)init
{
[super init];
expectedRaise = 0.05;
personName = #"New Person";
return self;
}
- (void)dealloc
{
[personName release];
[super dealloc];
}
#end
MyDocument.h:
#import <Cocoa/Cocoa.h>
#interface MyDocument : NSDocument
{
NSMutableArray *employees;
}
#property (retain) NSMutableArray *employees;
#end
MyDocument.mm:
#import "MyDocument.h"
#import "Person.h"
#implementation MyDocument
#synthesize employees;
- (id)init
{
if (![super init])
return nil;
employees = [[NSMutableArray alloc] init];
return self;
}
- (void)dealloc
{
[employees release];
[super dealloc];
}
- (void)windowControllerDidLoadNib:(NSWindowController *) aController
#end
And the sample works fine.(A blank table at first and you can add or delete record).
Now I tried to add some records to the array so that the blank table would have
someting in it at first.
Here's what I'v tried(inside the init method):
[self willChangeValueForKey:#"employees"];
Person *p1 = [[Person alloc] init];
[employees addObject: [NSData dataWithBytes: &p1 length: sizeof(p1)]];
[self didChangeValueForKey:#"employees"];
But when I build and wrong I got the error msg:
[<NSConcreteData 0x422bf0> valueForUndefinedKey:]: this class is not key value coding-compliant for the key personName.
......
Can any one help me out of here? Thanks in advance ^_^
That seems like a very reasonable response... you added NSData to your array named employees; guessing from the names, and from the KVC, you probably meant to add p1 to your array instead. So, try:
[employees addObject:p1];
I'm having some trouble figuring out to call methods that I have in other classes
#import "myNewClass.h"
#import "MainViewController.h"
#implementation MainViewController
#synthesize txtUsername;
#synthesize txtPassword;
#synthesize lblUserMessage;
- (IBAction)calculateSecret {
NSString *usec = [self calculateSecretForUser:txtUsername.text
withPassword:txtPassword.text];
[lblUserMessage setText:usec];
[usec release];
}
...
myNewClass.h
#import <Foundation/Foundation.h>
#interface myNewClass : NSObject {
}
- (NSString*)CalculateSecretForUser:(NSString *)user withPassword:(NSString *)pwd;
#end
myNewClass.m
#import "myNewClass.h"
#implementation myNewClass
- (NSString*)CalculateSecretForUser:(NSString *)user withPassword:(NSString *)pwd
{
NSString *a = [[NSString alloc] initWithFormat:#"%# -> %#", user, pwd];
return a;
}
#end
the method CalculateSecretForUser always says
'MainViewController' may not respond to '-calculateSecretForUser:withPassword:'
what am I doing wrong here?
The keyword "self" means the instance of your current class. So you are sending the message calculateSecretForUser:withPassword to MainViewController which does not implements it. You should instantiate myNewClass and call it :
- (IBAction)calculateSecret {
myNewClass *calculator = [[myNewClass alloc] init];
NSString *usec = [calculator calculateSecretForUser:txtUsername.text
withPassword:txtPassword.text];
[lblUserMessage setText:usec];
[usec release];
[calculator release];
}