After fetching UITableView Section and Row… what does this code do?

Question

Can anyone explain me what this code does after getting NSArray....

- (UIViewController *)sampleForIndexPath:(NSIndexPath *)indexPath {

    NSArray *samples = [samples_ objectAtIndex:indexPath.section];
    Class clazz = [samples objectAtIndex:indexPath.row];
    UIViewController *instance = [[clazz alloc] initWithNibName:nil bundle:nil];
    return [instance autorelease];
  }

I am getting NSArray of Section... then how can we assign the values of the row to a Class??

Answer 1

Here the array samples contains the objects of type Class . You can create an instance of class directly using a class name or by using a Class object/variable. For example,

/* One Way */

// Create an instance of MyViewController deirectly
UIViewController *vc = [[MyViewController alloc] init];

/* Another Way */

// The following line returns a class object
Class cls = NSClassFromString(@"MyViewController");
// The below is just for an example. This also returns a class object 
Class cls = [MyViewController class]; 
// Create an instance of MyViewController from the class object
UIViewController *vc = [[cls alloc] init];

Your code uses the second way to allocate the view controller object from the class object returned by [samples objectAtIndex:indexPath.row] .

Answer 2

After getting the array, it retrieves a particular Class using:

Class clazz = [samples objectAtIndex:indexPath.row];

and then it instantiates a UIViewController object using the class, and return that object:

UIViewController *instance = [[clazz alloc] initWithNibName:nil bundle:nil];
return [instance autorelease];