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];
}
Related
I found similar questions, but I couldn't solve my error. My error is:
No known class method for selector 'initWithUrl:sub:cont:cat:dat'
I've tried
#Synthesize,
self.variableName instead of _variableName,
adding [[MyClass init] alloc],
changing - to +
How can I fix it?
MyClass.h:
#import <Foundation/Foundation.h>
#interface MyClass : NSObject
-(id)init;
-(id)initWithURL:(NSURL *)url_ sub:(NSString *)subject_ cont:(NSString *)content_ cat:(NSString *)category_ dat:(NSString *)date_;
#property NSURL *bannerImageURL;
#property NSString *subject;
#property NSString *content;
#property NSString *category;
#property NSString *date;
#end
MyClass.m:
#import "MyClass.h"
#implementation MyClass
-(id)init {
self = [super init];
if (self) {
_bannerImageURL = [NSURL URLWithString:#"url0"];
_subject = #"sub0";
_content = #"cont0";
_category = #"cat0";
_date = #"dat0";
}
return self;
}
-(id)initWithURL:(NSURL *)url_ sub:(NSString *)subject_ cont:(NSString *)content_ cat:(NSString *)category_ dat:(NSString *)date_ {
self = [super init];
if (self) {
_bannerImageURL = url_;
_subject = subject_;
_content = content_;
_category = category_;
_date = date_;
}
return self;
}
#end
myViewController.m:
#import "myViewController.h"
#import "MyClass.h"
#implementation SimpleTableViewController
MyClass *news1;
- (void)viewDidLoad {
[super viewDidLoad];
NSURL *aUrl = [NSURL URLWithString:#"aUrl"];
// Error occurs here.
news1 = [MyClass initWithURL:aUrl sub:#"aSub" cont:#"aCont" cat:#"aCat" dat:#"aDat"];
}
I think you mean:
news1 = [[MyClass alloc] initWithURL:aUrl sub:#"aSub" cont:#"aCont" cat:#"aCat" dat:#"aDat"];
This is a standard pattern in Objective-C: call [SomeClass alloc] to create a new instance, then immediately call some initializer method on it. Initializers are instance methods which must be called on an instance of a class, whereas alloc is a class method that is called on the class itself (and which returns a newly allocated instance of that class).
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.
Okay, so I've been working on the Stanford iOS development course that they have posted for free online. I've been working on figuring out how to make a programable variable. It has been working fine so far, aside from the fact that I think the following lines of code are programming the variable to be #"x=" instead of the previous number entered.
The View Controller:
#import "ViewController.h"
#import "CalculatorBrain.h"
#interface ViewController()
#property (nonatomic) BOOL userIsInTheMiddleOfEnteringANumber;
#property (nonatomic) BOOL userPressedSomethingElse;
#property (nonatomic, strong) CalculatorBrain *brain;
#end
#implementation ViewController
#synthesize display;
#synthesize inputHistory;
#synthesize userPressedSomethingElse;
#synthesize userIsInTheMiddleOfEnteringANumber;
#synthesize brain = _brain;
- (CalculatorBrain *)brain
{
if (!_brain) _brain = [[CalculatorBrain alloc] init];
return _brain;
}
NSString *xValue = #"0";
- (IBAction)enterPressed
// A specific action if enter is pressed
{
[self.brain pushOperand:[self.display.text doubleValue]];
self.userIsInTheMiddleOfEnteringANumber = NO;
if (self.userPressedSomethingElse)
{
self.inputHistory.text = [self.inputHistory.text stringByAppendingString:#" "];
}
self.userPressedSomethingElse = NO;
}
- (IBAction)variableChanged:(id)sender
{
if (self.userIsInTheMiddleOfEnteringANumber)
{
[self enterPressed];
}
NSString *operation = [sender currentTitle];
xValue = [self.brain programVariable:operation];
self.inputHistory.text = [self.inputHistory.text stringByAppendingString:#"X="];
self.inputHistory.text = [self.inputHistory.text stringByAppendingString:xValue];
}
The Calculator Brain (the .m one):
#import "CalculatorBrain.h"
#interface CalculatorBrain()
#property (nonatomic,strong) NSMutableArray *operandStack;
#end
#implementation CalculatorBrain
#synthesize operandStack = _operandStack;
- (NSMutableArray *) operandStack
{
if (!_operandStack)
{
_operandStack = [[NSMutableArray alloc] init];
}
return _operandStack;
}
- (void) pushOperand:(double)operand
{
NSNumber *operandObject = [NSNumber numberWithDouble:operand];
[self.operandStack addObject:operandObject];
}
- (double)popOperand
{
NSNumber *operandObject = [self.operandStack lastObject];
if (operandObject) [self.operandStack removeLastObject];
return [operandObject doubleValue];
}
- (NSString *) programVariable: (NSString *) operation
{
double result = [self popOperand];
NSString *resultString = [NSString stringWithFormat:#"%.2d",result];
return resultString;
}
The .h Calculator Brain:
#import <Foundation/Foundation.h>
#interface CalculatorBrain : NSObject
- (void) pushOperand: (double) operand;
- (double) performOperation: (NSString *) operation;
- (NSString *) programVariable: (NSString *) operation;
#end
The button that is pushed says "x=", and because of some tracing statements I added, I have figured out that this is being set to xValue. However, I don't know how to fix it... Any ideas?
In your variableChanged:method, you possibly want if (!self.userIsInTheMiddleOfEnteringANumber) at the beginning. Note the logical negation, which I derive the need from the sense of your variable name. I see no way that variable is set, so I trust you are properly setting it elsewhere in your app.
Also, change the variable xValue to a instance variable on ViewController. It is currently a global static variable. If you have more than one ViewController objects created, you will have problems.
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];
}