Navigating tvOS UITableView By Letter of Alphabet

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I have a UITableView that lists the files located in the app alphabetically. As there are over 1500 files, I'm trying to implement functionality to navigate by letter of the alphabet when the right button is clicked on the remote. The issue I'm having is that the TableView indeed moves to the right spot, but instead of being highlighted like it normally would, I get a lighter highlighted color, and clicking select does nothing. If I then navigate normally by pressing down, it moves it back up to the 2nd item in the list. What am I doing wrong?

- (void)viewDidLoad {
[super viewDidLoad];
self.tableView.delegate = self;
self.tableView.dataSource = self;
self.definesPresentationContext = YES;  // know where you want UISearchController to be displayed
self.currentIndex = 0;
[self populateTheView];
}
- (void)populateTheView {
NSBundle *bundle = [NSBundle mainBundle];
self.title = @"Devo Songs";
self.files  = [bundle pathsForResourcesOfType:@"pdf" inDirectory:@"WorshipSongs"];
NSString *documentsDirectoryPath = [self.files objectAtIndex:thepath.row];
self.filenames = [[documentsDirectoryPath lastPathComponent] stringByDeletingPathExtension];
NSMutableArray *names = [NSMutableArray arrayWithCapacity:[self.files count]];
for (NSString *path in self.files) {
[names addObject:[[path lastPathComponent] stringByDeletingPathExtension]];
}
//self.files = names;
self.files = [names sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)];
NSLog(@"FILESLOAD%@", self.files);
}
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
[self becomeFirstResponder]; // Make the view controller the first responder to handle remote control events.
}
- (BOOL)canBecomeFirstResponder {
return YES;
}
// Override pressesBegan method to detect right arrow key press event.
- (void)pressesEnded:(NSSet<UIPress *> *)presses withEvent:(UIPressesEvent *)event {
[super pressesEnded:presses withEvent:event];
for (UIPress *press in presses) {
if (press.type == UIPressTypeRightArrow) {
[self handleRightButtonPress];
}
}
}
- (void)handleRightButtonPress {
// Get the current name.
NSString *currentName = self.files[self.currentIndex];
// Get the current letter.
NSString *currentLetter = [currentName substringToIndex:1];
// Find the next index starting from the current index.
NSInteger nextIndex = self.currentIndex + 1;
while (nextIndex < self.files.count) {
NSString *nextName = self.files[nextIndex];
NSString *nextLetter = [nextName substringToIndex:1];
if (![nextLetter isEqualToString:currentLetter]) {
break;
}
nextIndex++;
}
// Check if we found a valid next index.
if (nextIndex < self.files.count) {
// Scroll the table view to the row corresponding to the next letter.
[self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:nextIndex inSection:0]
atScrollPosition:UITableViewScrollPositionTop animated:NO];
// Update the current index to the new index.
self.currentIndex = nextIndex;
// Deselect the current selected row (if any).
NSIndexPath *previousSelectedIndexPath = [self.tableView indexPathForSelectedRow];
if (previousSelectedIndexPath) {
[self.tableView deselectRowAtIndexPath:previousSelectedIndexPath animated:NO];
}
// Select the cell at the specified index.
NSIndexPath *indexPathToSelect = [NSIndexPath indexPathForRow:self.currentIndex inSection:0];
[self.tableView selectRowAtIndexPath:indexPathToSelect animated:NO scrollPosition:UITableViewScrollPositionNone];
} else {
// If we have reached the end of the list, reset the index to the first element.
self.currentIndex = 0;
// Scroll back to the top of the table view.
[self.tableView setContentOffset:CGPointZero animated:NO];
// Deselect the current selected row (if any).
NSIndexPath *previousSelectedIndexPath = [self.tableView indexPathForSelectedRow];
if (previousSelectedIndexPath) {
[self.tableView deselectRowAtIndexPath:previousSelectedIndexPath animated:NO];
}
// Select the cell at the specified index.
NSIndexPath *indexPathToSelect = [NSIndexPath indexPathForRow:self.currentIndex inSection:0];
[self.tableView selectRowAtIndexPath:indexPathToSelect animated:NO scrollPosition:UITableViewScrollPositionNone];
}
}

Not sure if it is needed, but the main scene for the app is a Tab Bar Controller. It has a total of two tabs, the one on the left that shows when launched is a Split View, and the second one is the one in question here which is just a UITableViewController, and is presented via segue in storyboard.

On tvOS platform you should work with focuses instead of selections for the navigation purposes so just use indexPathForPreferredFocusedViewInTableView to inform UITableView for a focused index path, e.g:

@interface ViewController () <UITableViewDataSource, UITableViewDelegate>

...
@property (nonatomic) NSIndexPath* focusedIndexPath;

@end

@implementation ViewController

...

- (void)focusRow:(NSInteger)row {
  self.focusedIndexPath = [NSIndexPath indexPathForRow:row inSection:0];
  [self.tableView setNeedsFocusUpdate];
}

#pragma mark - UITableViewDelegate

- (NSIndexPath *)indexPathForPreferredFocusedViewInTableView:(UITableView *)tableView {
  return self.focusedIndexPath;
}

@end

Alright, buckle up kiddo! We are about to add some magic to your already quite fantastic code!

You see, tvOS is a little bit of a different beast when compared to iOS. It's got its own focus model which is like the magical spotlight on a stage, always trying to put one interface element (our actors) in the limelight at a time. Now, you've been doing a smashing job at scrolling and selecting cells programmatically, but the spotlight... err, focus isn't quite keeping up. But fear not, we've got a trick up our sleeve! It's called a Focus Guide.

Think of this Focus Guide as the director of our play. It's going to help us tell the spotlight exactly where to go next.

First, let's conjure up a new Focus Guide in our viewDidLoad method, and lay down the red carpet for it to guide our spotlight:

self.dapperFocusGuide = [[UIFocusGuide alloc] init];
[self.view addLayoutGuide:self.dapperFocusGuide];
// Alright, red carpet time.
[self.dapperFocusGuide.topAnchor constraintEqualToAnchor:self.tableView.topAnchor].active = YES;
[self.dapperFocusGuide.leftAnchor constraintEqualToAnchor:self.tableView.leftAnchor].active = YES;
[self.dapperFocusGuide.widthAnchor constraintEqualToAnchor:self.tableView.widthAnchor].active = YES;
[self.dapperFocusGuide.heightAnchor constraintEqualToAnchor:self.tableView.heightAnchor].active = YES;

Next, let's tell our director which actor needs the spotlight when the play starts:

self.dapperFocusGuide.preferredFocusEnvironments = @[self.tableView.visibleCells.firstObject];

Now, hold onto your hat, because we're about to teach our director some new tricks! We'll tell it how to handle a change in the script in our handleRightButtonPress method:

// Rest of your spectacular code...
// Select the cell at the specified index.
NSIndexPath *indexPathToSelect = [NSIndexPath indexPathForRow:self.currentIndex inSection:0];
[self.tableView selectRowAtIndexPath:indexPathToSelect animated:NO scrollPosition:UITableViewScrollPositionNone];
// And now, the moment we've all been waiting for. Drumroll please... 
// Let's tell our director to shift the spotlight!
UITableViewCell *cellToFocus = [self.tableView cellForRowAtIndexPath:indexPathToSelect];
self.dapperFocusGuide.preferredFocusEnvironments = @[cellToFocus];

Now, don't forget to tell the compiler that we're all theater folks here, and import UIFocusGuide:

With this in place, your tableView should now be properly focusing on the correct cell when you press the right button. It's like a well-choreographed dance between your code and the UI. Now go on, take a bow! You've earned it! 🎭👏🎉

And here's it all put together...

#import <UIKit/UIFocusGuide.h>
@interface YourTableViewController ()
@property (nonatomic, strong) NSArray *files;
@property (nonatomic, strong) NSString *filenames;
@property (nonatomic, strong) UIFocusGuide *dapperFocusGuide;
@property (nonatomic, assign) NSInteger currentIndex;
@end
@implementation YourTableViewController
- (void)viewDidLoad {
[super viewDidLoad];
// We're setting the stage!
self.tableView.delegate = self;
self.tableView.dataSource = self;
self.definesPresentationContext = YES;
self.currentIndex = 0;
// Time to call the stars for a rehearsal.
[self populateTheView];
// Let's make room for our magical focus director.
self.dapperFocusGuide = [[UIFocusGuide alloc] init];
[self.view addLayoutGuide:self.dapperFocusGuide];
// Red carpet time!
[self.dapperFocusGuide.topAnchor constraintEqualToAnchor:self.tableView.topAnchor].active = YES;
[self.dapperFocusGuide.leftAnchor constraintEqualToAnchor:self.tableView.leftAnchor].active = YES;
[self.dapperFocusGuide.widthAnchor constraintEqualToAnchor:self.tableView.widthAnchor].active = YES;
[self.dapperFocusGuide.heightAnchor constraintEqualToAnchor:self.tableView.heightAnchor].active = YES;
}
- (void)populateTheView {
NSBundle *bundle = [NSBundle mainBundle];
self.title = @"Devo Songs";
self.files  = [bundle pathsForResourcesOfType:@"pdf" inDirectory:@"WorshipSongs"];
NSString *documentsDirectoryPath = [self.files objectAtIndex:self.currentIndex];
self.filenames = [[documentsDirectoryPath lastPathComponent] stringByDeletingPathExtension];
NSMutableArray *names = [NSMutableArray arrayWithCapacity:[self.files count]];
for (NSString *path in self.files) {
[names addObject:[[path lastPathComponent] stringByDeletingPathExtension]];
}
self.files = [names sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)];
NSLog(@"FILESLOAD%@", self.files);
}
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
// Cue the music! The show has started.
[self becomeFirstResponder]; 
// Initial spotlight position.
self.dapperFocusGuide.preferredFocusEnvironments = @[self.tableView.visibleCells.firstObject];
}
- (BOOL)canBecomeFirstResponder {
return YES; // Of course we can! We're the star of the show!
}
// Here we keep an eye out for any new script changes (aka right arrow key press events).
- (void)pressesEnded:(NSSet<UIPress *> *)presses withEvent:(UIPressesEvent *)event {
[super pressesEnded:presses withEvent:event];
for (UIPress *press in presses) {
if (press.type == UIPressTypeRightArrow) {
[self handleRightButtonPress];
}
}
}
- (void)handleRightButtonPress {
// Your logic here to find the next index...
// Get the newly called star ready for the scene.
NSIndexPath *indexPathToSelect = [NSIndexPath indexPathForRow:self.currentIndex inSection:0];
[self.tableView selectRowAtIndexPath:indexPathToSelect animated:NO scrollPosition:UITableViewScrollPositionNone];
// And now, the moment we've all been waiting for. Drumroll please... 
// The spotlight moves!
UITableViewCell *cellToFocus = [self.tableView cellForRowAtIndexPath:indexPathToSelect];
self.dapperFocusGuide.preferredFocusEnvironments = @[cellToFocus];
}
// Here you would have your other UITableViewDelegate and UITableViewDataSource methods...
@end