macOS Help me with Objective-C

[anonymous3025]

Hello, I am new to objective-C and Cocoa. I tried to make an app where you enter text and there is an if statement that decides what happens. Except even if a enter the correct info the else statement still executes. Here is the code:

//This is the header file
#import <Cocoa/Cocoa.h>

@interface Who : NSObject {
IBOutlet id input;
IBOutlet id text;
}
- (IBAction)whoid)sender;
@end


//This is the implementation file
#import "Who.h"

@implementation Who
- (IBAction)whoid)sender {
if (input==@"Tim")
{
[text setStringValue"Hi tim"];
}
else
{
[text setStringValue"I do not know you"];
}
}
@end

 

[CaptainZap]

If you want to compare two strings, the == doesn't work because input is just a pointer to the data. So you need to use the [string isEqualTo: string2] which should work for the if statement.

Edit: Oh and if your input is a NSTextField you should use the stringValue method... So your if statment should look like this.

if ([[input stringValue] isEqualToString: @"Tim"]) {
	[text setStringValue:@"Hi tim"];
}
else {
	[text setStringValue:@"I do not know you"];
}

And for future reference, try to include your code in tags, it makes it easier to read

 

[Soulstorm]

//This is the header file
#import <Cocoa/Cocoa.h>

@interface Who : NSObject {
	IBOutlet id input;
	IBOutlet id text;
}
- (IBAction)who:(id)sender;
@end


//This is the implementation file
#import "Who.h"

@implementation Who
- (IBAction)who:(id)sender {
	if (input==@"Tim")
	{
		[text setStringValue:@"Hi tim"];
	}
	else
	{
		[text setStringValue:@"I do not know you"];
	}
}
@end

Things just don't work that way in objective C, my friend.

The 'id' is actually a pointer to an object. Pointers have different behaviors or operators such as '=='. I think you should look into pointers. Understand them completely before proceeding to learning ObjC, because problems may arise later with memory management.

 

[Eraserhead]

Don't use id as the type for the point, use NSTextField or whatever...

And you use [foo isEqualTo"bar] to check equality of objective C objects.

 

[NexesDev]

Your code should look like this

Your code should look something like this, it will work.

Header file:

#import <Cocoa/Cocoa.h>


@interface mainController : NSObject
{
IBOutlet NSTextField *inputText;
IBOutlet NSTextField *displayText;
}

-(IBAction)sendTextNSButton *)sender;

@end

Main File :

@implementation mainController

-(IBAction)sendTextNSButton *)sender
{
if ([[inputText stringValue] isEqualTo"Tim"])
{
[displayText setStringValue"I know you"];
}
if ([[inputText stringValue] isNotEqualTo"Tim"])
{
[displayText setStringValue"I dont know you"];
}

}

@end