How can I force focus to change to a specific view in tvOS? - objective-c

Question

I am implementing custom code to handle a click on the Menu button on the Siri Remote.
How can I force focus to change to my custom menu when pressing the menu button?

Answer 1

For ios 10 you should use preferredFocusEnvironments instead of preferredFocusedView .
In below example if you want to focus on button then see below code.
#IBOutlet weak var button: UIButton!
override var preferredFocusEnvironments: [UIFocusEnvironment] {
return [button]
}
override func viewDidLoad() {
super.viewDidLoad()
setNeedsFocusUpdate()
updateFocusIfNeeded()
}

Answer 2

Finally figured it out myself. You have to override the preferredFocusedView property of your UIView or UIViewController.
In Swift it works like this:
func myClickHandler() {
someCondition = true
self.setNeedsFocusUpdate()
self.updateFocusIfNeeded()
someCondition = false
}
override weak var preferredFocusedView: UIView? {
if someCondition {
return theViewYouWant
} else {
return defaultView
}
}
I can't quite remember how to override getters in Objective-C so if someone want to post that I'll edit the answer.

Answer 3

Here is another implementation based on Slayters answer above. Its slightly more elegant I think than using the conditional booleans.
Put this in your viewcontroller
var viewToFocus: UIView? = nil {
didSet {
if viewToFocus != nil {
self.setNeedsFocusUpdate();
self.updateFocusIfNeeded();
}
}
}
override weak var preferredFocusedView: UIView? {
if viewToFocus != nil {
return viewToFocus;
} else {
return super.preferredFocusedView;
}
}
Then to use it in your code
viewToFocus = myUIView;

Answer 4

here is the objective C
- (UIView *)preferredFocusedView
{
if (someCondition) {
// this is if your menu is a tableview
NSIndexPath *ip = [NSIndexPath indexPathForRow:2 inSection:0];
UITableViewCell * cell = [self.categoryTableView cellForRowAtIndexPath:ip];
return cell;
}
return self.view.preferredFocusedView;
}
in your viewDidLoad or view did appear do something like this:
UIFocusGuide *focusGuide = [[UIFocusGuide alloc]init];
focusGuide.preferredFocusedView = [self preferredFocusedView];
[self.view addLayoutGuide:focusGuide];
if you want to do it when it first launches

Answer 5

Here's a nice little Swift 2 copy / paste snippet:
var myPreferredFocusedView: UIView?
override var preferredFocusedView: UIView? {
return myPreferredFocusedView
}
func updateFocus(to view: UIView) {
myPreferredFocusedView = napDoneView
setNeedsFocusUpdate()
updateFocusIfNeeded()
}
Use it like this:
updateFocus(to: someAwesomeView)

Answer 6

#elu5ion 's answer, but in objective-c
first declare:
#property (nonatomic) UIView *preferredView;
Set these methods:
-(void)setPreferredView:(UIView *)preferredView{
if (preferredView != nil) {
_preferredView = nil;
UIFocusGuide *focusGuide = [[UIFocusGuide alloc]init];
[self.view addLayoutGuide:focusGuide];
focusGuide.preferredFocusedView = [self preferredFocusedView];
[self setNeedsFocusUpdate];
[self updateFocusIfNeeded];
}
_preferredView = preferredView;
}
- (UIView *)preferredFocusedView {
if (_preferredView) {
return _preferredView;
}
return self.view.preferredFocusedView;
}