CODEWITHSUNDEEP
iosobjective-cclass
Brian Smith
Brian Smith

Reputation: 31

How to call a method on an id class object?

I'm trying to write code that'll simplify the addition of new functions in an internal tool build. There is a UITableView with each cell being a button for a function that'll segue into another view.

Each function is in its own class file. Currently, this is the way I'm doing it.

In the view controller, I initialize the class in a method, then I segue into its view controller

- (void)resetButtonTouched {
    [ResetClass *reset = [[ResetClass alloc] initWithNumber num];
    [self.navigationController pushViewController: reset animated: YES];
}

Then for cellForRowAtIndexPath I create the cell 

cell.textLabel.text = @"Reset";

Then in the didSelectRowAtIndexPath I create the button response

[_viewController resetButtonTouched];

And I do that for the 10 other functions, so

[Function2 *function2 = [[Function2 alloc] initWithNumber num]; [Function3 *function3 = [[Function2 alloc] initWithNumber num];

etc...

I'd like to simplify this so I only have to register a class in one place and it'll automatically add the cell and connect the button. For cellForRowAtIndexPath and didSelectRowAtIndexPath I can just get it to look in an array based on indexPath.row. But, I need a way to store the class objects in an array and initialize them when called upon.

I'm thinking I can have every function that gets added here to have class methods that'll

and a normal method to be called after initialization to do its stuff.

I want to write something where if I just write these two lines,

ResetFunction *reset;
[self registerFunction:reset];

It'll do everything I did above (create a working button that calls that class object)

I'm thinking of having an array that will store all the different class objects, call it allFunctions, and a method runFunction that'll do the initialization and segueing. Then in cellForRowAtIndexPath it'll just be 

cell.textLabel.text = [allFunctions[indexPath.row] getTitle];

and in didSelectRowAtIndexPath it'll call [_viewController runFunction:allFunctions[indexPath.row]];

How would I do that? I tried creating a method with an id * parameter, which takes the class object, with the intent of storing that in the array allFunctions I'm having trouble making a method that'll store all the functions because it's giving me the "implicit conversion of a non-objective-c pointer to autoreleasing id is disallowed with ARC" when I try to call [self registerClass:reset].

What should I do?

Upvotes: 2

Views: 702

Answers (1)

Ken Thomases
Ken Thomases

Reputation: 90571

Class objects are objects, too. Rather than id, you use a Class variable to hold a reference to a class object.

Class theClass = [ResetClass class];

You can store these in an NSMutableArray.

[someArray addObject:theClass];

You can later retrieve the class and send messages to it:

Class theClass = someArray[index];
id object = [[theClass alloc] init];

If you need to be able to query each class object for a title property, you'll need to implement on each class that you add to your array. For example, this is a class method implementing such a class property:

+ (NSString*) title
{
    return @"Blah, blah, blah";
}

You could obtain it using code like:

Class theClass = someArray[index];
NSString* title = [theClass title];
// ... code which uses the title ...

Upvotes: 3

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