First of all your View shouldn't ask data from Presenter - it's violation of VIPER architecture.
The View is passive. It waits for the Presenter to give it content to display; it never asks the Presenter for data.
As for you question:
It's better to keep current view state in Presenter, including all data. Because it's providing communications between VIPER parts based on state.
But in other way Presenter shouldn't know anything about UIKit, so UITableViewDataSource and UITableViewDelegate should be part of View layer.
To keep you ViewController in good shape and do it in 'SOLID' way, it's better to keep DataSource and Delegate in separate files. But these parts still should know about presenter to ask data. So I prefer to do it in Extension of ViewController
All module should look something like that:
View
ViewController.h
extern NSString * const TableViewCellIdentifier;
@interface ViewController
@end
ViewController.m
NSString * const TableViewCellIdentifier = @"CellIdentifier";
@implemntation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
[self.presenter setupView];
}
- (void)refreshSongs {
[self.tableView reloadData];
}
@end
ViewController+TableViewDataSource.h
@interface ViewController (TableViewDataSource) <UITableViewDataSource>
@end
ViewController+TableViewDataSource.m
@implementation ItemsListViewController (TableViewDataSource)
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [self.presenter songsCount];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
Song *song = [self.presenter songAtIndex:[indexPath.row]];
// Configure cell
return cell;
}
@end
ViewController+TableViewDelegate.h
@interface ViewController (TableViewDelegate) <UITableViewDelegate>
@end
ViewController+TableViewDelegate.m
@implementation ItemsListViewController (TableViewDelegate)
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
Song *song = [self.presenter songAtIndex:[indexPath.row]];
[self.presenter didSelectItemAtIndex:indexPath.row];
}
@end
Presenter
Presenter.m
@interface Presenter()
@property(nonatomic,strong)NSArray *songs;
@end
@implementation Presenter
- (void)setupView {
[self.interactor getSongs];
}
- (NSUInteger)songsCount {
return [self.songs count];
}
- (Song *)songAtIndex:(NSInteger)index {
return self.songs[index];
}
- (void)didLoadSongs:(NSArray *)songs {
self.songs = songs;
[self.userInterface refreshSongs];
}
@end
Interactor
Interactor.m
@implementation Interactor
- (void)getSongs {
[self.service getSongsWithCompletionHandler:^(NSArray *songs) {
[self.presenter didLoadSongs:songs];
}];
}
@end
