I would like to have only one class for control my menu.
I try used this:
In the .h
#define Generic ((AppDelegate*)[[UIApplication sharedApplication] delegate])
#import <UIKit/UIKit.h>
#interface Generic : UIViewController
- (IBAction)photo:(id)sender;
#property (nonatomic, strong) NSString *apareceMenu;
#end
in the .m
- (IBAction)photo:(id)sender{
NSLog(#"Ok");
}
Now i need read the - (IBAction)photo in other class, But i don't know how.
I believe to be something
[Generic photo];
Could someone help me please?
Follow the instructions in this post:
How to call method from one class in another (iOS) https://stackoverflow.com/a/9731162/2274694
[Generic photo:] is correct method to call the function. Before the you must do this steps in another class.
Generic *genericObj = [[Generic alloc]initWithNibName:#"Generic" bundle:nil];
then you call your class like,
[genericObj photo];
create object for Generic class and call photo via that object
[genericObj photo];
Related
I m trying to passing values from second class to first class for that I am using protocol and delegate process. Whenever I run my program I am facing below Issue.
No Type or Protocol Named 'locateMeDelegate'
Viewcontroller A .h
#interface first : UIViewController < locateMeDelegate > { }
In my case the issue was caused by importing the delegate's header file to the delegator's class .h file. This seems to create a sort of vicious circle. As soon as I deleted the import statement of the delegate's header from the delegator's .h file, the error went away.
Tipically, if you intend your protocol to be used by other classes you must declare it in the header file like this:
// MyClass.h
#protocol MyProtocol;
#interface MyClass : NSObject
#end
#protocol MyProtocol
- (void) doSomething: (MyClass*) m;
#end
After you declare it, you should implement the methods of the protocol in the implementation file, which should conform to the protocol like this:
// MyClass.m
#implementation MyClass <MyProtocol>
pragma mark - MyProtocol methods
- (void) doSomething: (MyClass *)m {
// method body
}
#end
After these two steps you're ready to use you protocol in any class you desire. For example, let's say we want to pass data to MyClass from other class (e.g. OtherClass.h). You should declare in OtherClass.h a property so that we can refer to MyClass and execute the protocol. Something like this:
// OtherClass.h
#import MyClass.h
#interface OtherClass : NSObject
#property (weak) id<MyProtocol> delegate;
#end
You don't forget to import the header file where you declared your protocol, otherwise Xcode will prompt No Type or protocol named "MyProtocol"
id<MyProtocol> delegate; means you can set as the delegate of OtherClass any object (id) that conforms to the MyProtocol protocol (<MyProtocol>)
Now you can create an OtherClass object from MyClass and set its delegate property to self. Like this:
// MyClass.m
- (void)viewDidLoad() {
OtherClass *otherClass = [[OtherClass alloc] init];
otherClass.delegate = self;
}
It's possible to set the delegate to self because the delegate can be any object and MyClass conforms to MyProtocol.
I hope this can help. If you want to know more about protocols you can refer to this two websites:
Working with Protocols - Apple Documentation
Ry's Objective-C Tutorial (This one is easy to pick up)
I also faced the same issue and it seems the error is from Xcode itself. Please Try running on Physical device. This would solve the issue faced.
Here is my TextValidator class:
//TextValidator.h
#import <Foundation/Foundation.h>
#interface TextValidator : NSObject
- (BOOL) isValidPassword:(NSString *)checkPassword;
- (BOOL) isValidEmail:(NSString *)checkString;
- (BOOL) isEmpty:(NSString *)checkString;
#end
// TextValidator.m
#import "TextValidator.h"
#implementation TextValidator
- (BOOL) isEmpty:(NSString *)checkString
{
return YES;
}
- (BOOL) isValidPassword:(NSString *)checkPassword
{
return YES;
}
- (BOOL) isValidEmail:(NSString *)checkString
{
return YES;
}
#end
This is the way I try to initialise the TextValidator class in ViewController.m:
//ViewController.h
#import <Foundation/Foundation.h>
#interface SignUpViewController : UIViewController <UITextFieldDelegate>
#end
//ViewController.m
#import "SignUpViewController.h"
#import "TextValidator.h"
#interface SignUpViewController ()
#property TextValidator *myValidator;
#end
#implementation SignUpViewController
- (void)viewDidLoad
{
[[self.myValidator alloc] init]; //iOS error: No visible #interface for 'TextValidator' declares the selector 'alloc'*
[super viewDidLoad];
}
#end
When I try to compile the code I get the following error:
No visible #interface for 'TextValidator' declares the selector 'alloc'.
TextValidator class inherits from NSObject and as far as I know init and alloc functions are already defined at the base class. So why does the program gives such an error?
Note that, I already checked this topic and it doesn't work for me.
My psychic debugger, without reading your code, tells me you're calling alloc on an object instance, rather than a class. The alloc method is a static method defined by classes (typically inherited from NSObject) that returns a new instance of the underlying object. You can't ask an instance to allocate itself!
Now looking at the code, I see that you want:
self.myValidator = [[TextValidator alloc] init];
to construct a new instance, and assign it to the myValidator property.
Replace
[[self.myValidator alloc] init];
with
self.myValidator = [[TextValidator alloc] init];
The error signals that you have not implemented the alloc instance method for self.myValidator, which is true. But that's a class method that applies for all NSObject objects.
Your syntax of creating object is incorrect. Correct code:
self.myValidator = [[TextValidator alloc] init];
If you experience this randomly (like when you are changing branches), not because you forgot to declare selector.
Go to file inspector > Target Membership
uncheck the targets
then check it again
This will refresh your project.pbxproj
Then if you build, you'll see your real problem
For Others :
Check the varible name is not like the class name.
Well it happend to me.
XXXViewController * XXXViewController = [[XXXViewController alloc] init];
Don't tell anyone like I did right now.
For those who get the error of "no visible #interface for declares the selector ..."
such an error usually happens when you have mistyped the name of the method, or that method doesn't belong to that class at all and doesn't exist in your class
I had this problem today and solved it on my own. Basically you could also not be satisfying all the requirements of the function / procedure.
Go into the class itself and make sure your declaring all the requirements.
I took the class out of the header library and compared it word for word to verify it matches the function using it.
I have 2 classes geoViewController and geoMainViewController
I have a method in the geoMainViewController called getFoo
It looks like this:
- (NSString *)getFoo
{
NSString* foo = #"This is foo";
return foo;
}
I am trying to call getFoo from the geoViewController class.
I have #import "geoMainViewController.h" in my geoViewController m file.
I am trying instantiate the geoMainViewController class and call the getFoo method from the viewDidLoad in my geoViewController class like this:
- (void)viewDidLoad
{
[super viewDidLoad];
geoMainViewController* mainVC = [[geoMainViewController alloc] init];
NSString* myFoo = [mainVC getFoo];
}
It seems to be instantiating the geoMainViewController class fine but I am getting an error on NSString* myFoo = [mainVC getFoo];
The error is - no visible #interface for 'geoMainViewController' declares the selector 'getFoo'
I am sure I am missing a step because I am very new to Objective C. I am just not sure what I am doing wrong.
Any help on this would be great.
Thanks!
In your geoMainViewController.h you should declare the selector to be visible:
-(NSString *)getFoo;
Did you put - (NSString *)getFoo in your geoMainViewController.h ?
You have to make those methods visible to the outside of your object through the .h file, so other objects know which selectors they respond to. Did the autoComplete fill in the message per chance?
#import <Foundation/Foundation.h>
#interface
{
}
#property (nonatomic,strong) ;
#property (nonatomic,strong) ;
#property (nonatomic, strong) ;
- (NSString *)getFoo
#end
EDIT: (You could also just make Foo a property by the way)
Did you declare it in your header file?
Header file contains all the function declarations in the .h file and you only include the .h file in your class. So it depends on .h file. .h file will have all the functions as the .m file.
Hope it helps you.
You are misunderstanding how to use a view controller. While you can technically create an instance of a view controller in order to call one of its methods, you shouldn't do so. The normal approach is that the view controller is part of the view hierarchy and you can call methods on it when you have access to that instance. You are missing something fundamental here.
Your actual error is a missinh method declaration, I would suspect, but you have bigger problems to solve first.
I am using forward declaration in the calling Class.
.h file in ClassTwo
#class ClassOne
#property(nonatomic,retain) ClassOne *class_One;
.m file
#synthesize class_One;
Then i am trying to call this method in ClassOne
[self.class_One callingThisMethodFromClassTwo];
On the other hand if i create a shared instance in ClassOne and use it as a class method it works
[[ClassOne Shared] nowItWorks];
Sorry if this is a silly question i am very new
try to allocate class_One instance and add #import "ClassOne.h" to headers on top of your classtwo.m
self.class_One= [[ClassOne alloc]init];
[self.class_One callingThisMethodFromClassTwo];
If [self.class_One callingThisMethodFromClassTwo]; fails... this directly refers that
Either class_One is not alloc+init-ed.
Or callingThisMethodFromClassTwo is a private/protected method.
Or callingThisMethodFromClassTwo is a class method.
I am recommending you to use Protocol/Delegate for this issue.
You Should declare a delegate protocol for your class. An example of a delegate protocol and interface for class Foo might be in this way:
#protocol MyClassDelegate
// Required means if they want to use the delegate they
// have to implement it.
#required
// method that you want to call from another class.
- (void)taskComplete:(BOOL)complete;
#end
#interface MyClass : NSObject
{
// We don't know what kind of class is going to adopt us at
//compile time, that's why this is an id
id delegate;
}
#property (nonatomic, assign) id delegate;
(void)taskComplete;
(void)doSomeTask;
Suppose you have a complex project and don’t want to create lots of
linkages between your classes, in that case delegation like this is going to be your best way to implement. It’s like having function pointers ad callbacks, but the communication goes both ways easily. Time to adopt our protocol and actually use it in a class.
myClass = [[MyClass alloc] init];
// Very important. If we don't let myClass know who the delegate
// is we'll never get the protocol methods called to us.
[myClass setDelegate:self];
In this you can call method from another class. I hope this will help you.
I have created a math based application in Xcode 4.4. I am using tabbar based app with the help of storyboard.
I have written all my math functions in a separate class called CalculationMethods which is the subclass of NSObject.
My ViewController:
// FirstViewController.h
#import <UIKit/UIKit.h>
#import "CalculationMethods.h"
#interface FirstViewController : UIViewController
#end
// FirstViewController.m
#import "FirstViewController.h"
#import "CalculationMethods.h"
#interface FirstViewController ()
#end
#implementation FirstViewController
- (void)viewDidLoad
{
[super viewDidLoad];
NSLog(#"%f",[self julianDateFinder: [self currentDayMonthAndYearFinder]]);
}
#end
As you can see I have included my CalculationMethod.h file in both FirstViewController.h and the FirstViewController.m file, but when I use the methods of that class such as julianDateFinder and currentDayMonthAndYearFinder, Xcode errors, saying:
"No Visible #interface for 'FirstViewController' declares the selector 'CurrentDayMonthAndYearFinder'"
I am new to iOS and XCode. Can anyone help me solve the error?
In the FirstViewController, to use any of the methods in the CalculationMethods class, you need to create an instance of CalculationMethods. And then access a method using this syntax: [instanceOfCalculationMethods aMethodInCalculationMethods];
For example in your case, try this:
In the FirstViewController.h file, before the #end:
CalculationMethods *_calculationMethods;
And in the viewDidLoad method:
_calculationMethods = [CalculationMethods alloc] init];
NSLog(#"%f",[_calculationMethods julianDateFinder: [_calculationMethods currentDayMonthAndYearFinder]]);
I think you're misunderstanding how Objective C works slightly.
Without adding details of the CalculationMethods.h header file I can't help you much, but that compiler warning is telling you that FirstViewController doesn't have the method currentDayMonthAndYearFinder.
The reason that this is the case is because you're calling performing the selector CurrentDayMonthAndYearFinder on self which in the context of your FirstViewController instance is in fact the instance of FirstViewController
You said it yourself that your method CurrentDayMonthAndYearFinder is on your CalculatorMethods class so I suggest you either create an instance of your CalculatorMethods class or call the class method named CurrentDayMonthAndYearFinder on your CalculatorMethods class.
The problem here is weather or not you've defined instance methods or class methods.
Do yourself a favour and update your question with the contents of CalculationMethods.h