Struct UIFocusGuide

#[repr(C)]
pub struct UIFocusGuide { /* private fields */ }

Available on crate features UIFocusGuide and UILayoutGuide only.

UIFocusGuides are UILayoutGuide subclasses that participate in the focus system from within their owning view. A UIFocusGuide may be used to expose non-view areas as focusable.

See also Apple’s documentation

Implementations

impl UIFocusGuide

pub unsafe fn isEnabled(&self) -> bool

If disabled, UIFocusGuides are ignored by the focus engine, but still participate in layout. Modifying this flag allows you to conditionally enable or disable certain focus behaviors. YES by default.

pub unsafe fn setEnabled(&self, enabled: bool)

Setter for isEnabled.

pub unsafe fn preferredFocusEnvironments( &self, ) -> Retained<NSArray<ProtocolObject<dyn UIFocusEnvironment>>>

Available on crate feature UIFocus only.

Setting preferredFocusEnvironments to a non-empty array marks this guide’s layoutFrame as focusable. If empty, this guide is effectively disabled. If focused, the guide attempts to redirect focus to each environment in the array, in order, stopping when a focusable item in an environment has been found.

pub unsafe fn setPreferredFocusEnvironments( &self, preferred_focus_environments: Option<&NSArray<ProtocolObject<dyn UIFocusEnvironment>>>, )

Available on crate feature UIFocus only.

Setter for preferredFocusEnvironments.

pub unsafe fn preferredFocusedView(&self) -> Option<Retained<UIView>>

👎Deprecated

Available on crate features UIResponder and UIView only.

Setting a preferred focused view marks this guide’s layoutFrame as focusable, and if focused, redirects focus to its preferred focused view. If nil, this guide is effectively disabled.

pub unsafe fn setPreferredFocusedView( &self, preferred_focused_view: Option<&UIView>, )

👎Deprecated

Available on crate features UIResponder and UIView only.

This is a weak property. Setter for preferredFocusedView.

impl UIFocusGuide

Methods declared on superclass NSObject.

pub unsafe fn init(this: Allocated<Self>) -> Retained<Self>

pub unsafe fn new(mtm: MainThreadMarker) -> Retained<Self>

Methods from Deref<Target = UILayoutGuide>

pub unsafe fn layoutFrame(&self) -> CGRect

Available on crate feature objc2-core-foundation only.

pub unsafe fn owningView(&self) -> Option<Retained<UIView>>

Available on crate features UIResponder and UIView only.

pub unsafe fn setOwningView(&self, owning_view: Option<&UIView>)

Available on crate features UIResponder and UIView only.

This is a weak property. Setter for owningView.

pub unsafe fn identifier(&self) -> Retained<NSString>

pub unsafe fn setIdentifier(&self, identifier: &NSString)

Setter for identifier.

pub unsafe fn leadingAnchor(&self) -> Retained<NSLayoutXAxisAnchor>

Available on crate feature NSLayoutAnchor only.

pub unsafe fn trailingAnchor(&self) -> Retained<NSLayoutXAxisAnchor>

Available on crate feature NSLayoutAnchor only.

pub unsafe fn leftAnchor(&self) -> Retained<NSLayoutXAxisAnchor>

Available on crate feature NSLayoutAnchor only.

pub unsafe fn rightAnchor(&self) -> Retained<NSLayoutXAxisAnchor>

Available on crate feature NSLayoutAnchor only.

pub unsafe fn topAnchor(&self) -> Retained<NSLayoutYAxisAnchor>

Available on crate feature NSLayoutAnchor only.

pub unsafe fn bottomAnchor(&self) -> Retained<NSLayoutYAxisAnchor>

Available on crate feature NSLayoutAnchor only.

pub unsafe fn widthAnchor(&self) -> Retained<NSLayoutDimension>

Available on crate feature NSLayoutAnchor only.

pub unsafe fn heightAnchor(&self) -> Retained<NSLayoutDimension>

Available on crate feature NSLayoutAnchor only.

pub unsafe fn centerXAnchor(&self) -> Retained<NSLayoutXAxisAnchor>

Available on crate feature NSLayoutAnchor only.

pub unsafe fn centerYAnchor(&self) -> Retained<NSLayoutYAxisAnchor>

Available on crate feature NSLayoutAnchor only.

pub unsafe fn constraintsAffectingLayoutForAxis( &self, axis: UILayoutConstraintAxis, ) -> Retained<NSArray<NSLayoutConstraint>>

Available on crate features UIView and NSLayoutConstraint only.

pub unsafe fn hasAmbiguousLayout(&self) -> bool

Available on crate feature UIView only.

Methods from Deref<Target = NSObject>

pub fn doesNotRecognizeSelector(&self, sel: Sel) -> !

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>

pub fn class(&self) -> &'static AnyClass

Available on crate feature UIIndirectScribbleInteraction only.

Dynamically find the class of this object.

Panics

May panic if the object is invalid (which may be the case for objects returned from unavailable init/new methods).

Example

Check that an instance of NSObject has the precise class NSObject.

use objc2::ClassType;
use objc2::runtime::NSObject;

let obj = NSObject::new();
assert_eq!(obj.class(), NSObject::class());

pub unsafe fn get_ivar<T>(&self, name: &str) -> &T

where T: Encode,

👎Deprecated: this is difficult to use correctly, use Ivar::load instead.

Available on crate feature UIIndirectScribbleInteraction only.

Use Ivar::load instead.

Safety

The object must have an instance variable with the given name, and it must be of type T.

See Ivar::load_ptr for details surrounding this.

pub fn downcast_ref<T>(&self) -> Option<&T>

where T: DowncastTarget,

Available on crate feature UIIndirectScribbleInteraction only.

Attempt to downcast the object to a class of type T.

This is the reference-variant. Use Retained::downcast if you want to convert a retained object to another type.

Mutable classes

Some classes have immutable and mutable variants, such as NSString and NSMutableString.

When some Objective-C API signature says it gives you an immutable class, it generally expects you to not mutate that, even though it may technically be mutable “under the hood”.

So using this method to convert a NSString to a NSMutableString, while not unsound, is generally frowned upon unless you created the string yourself, or the API explicitly documents the string to be mutable.

See Apple’s documentation on mutability and on isKindOfClass: for more details.

Generic classes

Objective-C generics are called “lightweight generics”, and that’s because they aren’t exposed in the runtime. This makes it impossible to safely downcast to generic collections, so this is disallowed by this method.

You can, however, safely downcast to generic collections where all the type-parameters are AnyObject.

Panics

This works internally by calling isKindOfClass:. That means that the object must have the instance method of that name, and an exception will be thrown (if CoreFoundation is linked) or the process will abort if that is not the case. In the vast majority of cases, you don’t need to worry about this, since both root objects NSObject and NSProxy implement this method.

Examples

Cast an NSString back and forth from NSObject.

use objc2::rc::Retained;
use objc2_foundation::{NSObject, NSString};

let obj: Retained<NSObject> = NSString::new().into_super();
let string = obj.downcast_ref::<NSString>().unwrap();
// Or with `downcast`, if we do not need the object afterwards
let string = obj.downcast::<NSString>().unwrap();

Try (and fail) to cast an NSObject to an NSString.

use objc2_foundation::{NSObject, NSString};

let obj = NSObject::new();
assert!(obj.downcast_ref::<NSString>().is_none());

Try to cast to an array of strings.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);
// This is invalid and doesn't type check.
let arr = arr.downcast_ref::<NSArray<NSString>>();

This fails to compile, since it would require enumerating over the array to ensure that each element is of the desired type, which is a performance pitfall.

Downcast when processing each element instead.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);

for elem in arr {
    if let Some(data) = elem.downcast_ref::<NSString>() {
        // handle `data`
    }
}

Trait Implementations

impl AsRef<AnyObject> for UIFocusGuide

fn as_ref(&self) -> &AnyObject

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<NSObject> for UIFocusGuide

fn as_ref(&self) -> &NSObject

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<UIFocusGuide> for UIFocusGuide

fn as_ref(&self) -> &Self

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<UILayoutGuide> for UIFocusGuide

fn as_ref(&self) -> &UILayoutGuide

Converts this type into a shared reference of the (usually inferred) input type.

impl Borrow<AnyObject> for UIFocusGuide

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for UIFocusGuide

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl Borrow<UILayoutGuide> for UIFocusGuide

fn borrow(&self) -> &UILayoutGuide

Immutably borrows from an owned value.

impl ClassType for UIFocusGuide

const NAME: &'static str = "UIFocusGuide"

The name of the Objective-C class that this type represents.

type Super = UILayoutGuide

The superclass of this class.

type ThreadKind = dyn MainThreadOnly

Whether the type can be used from any thread, or from only the main thread.

fn class() -> &'static AnyClass

Get a reference to the Objective-C class that this type represents.

fn as_super(&self) -> &Self::Super

Get an immutable reference to the superclass.

impl Debug for UIFocusGuide

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for UIFocusGuide

type Target = UILayoutGuide

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Hash for UIFocusGuide

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Message for UIFocusGuide

fn retain(&self) -> Retained<Self>

where Self: Sized,

Increment the reference count of the receiver.

impl NSCoding for UIFocusGuide

unsafe fn encodeWithCoder(&self, coder: &NSCoder)

where Self: Sized + Message,

unsafe fn initWithCoder( this: Allocated<Self>, coder: &NSCoder, ) -> Option<Retained<Self>>

where Self: Sized + Message,

impl NSObjectProtocol for UIFocusGuide

fn isEqual(&self, other: Option<&AnyObject>) -> bool

where Self: Sized + Message,

Check whether the object is equal to an arbitrary other object.

fn hash(&self) -> usize

where Self: Sized + Message,

An integer that can be used as a table address in a hash table structure.

fn isKindOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of the class, or one of its subclasses.

fn is_kind_of<T>(&self) -> bool

where T: ClassType, Self: Sized + Message,

👎Deprecated: use isKindOfClass directly, or cast your objects with AnyObject::downcast_ref

Check if the object is an instance of the class type, or one of its subclasses.

fn isMemberOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of a specific class, without checking subclasses.

fn respondsToSelector(&self, aSelector: Sel) -> bool

where Self: Sized + Message,

Check whether the object implements or inherits a method with the given selector.

fn conformsToProtocol(&self, aProtocol: &AnyProtocol) -> bool

where Self: Sized + Message,

Check whether the object conforms to a given protocol.

fn description(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object.

fn debugDescription(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object to use when debugging.

fn isProxy(&self) -> bool

where Self: Sized + Message,

Check whether the receiver is a subclass of the NSProxy root class instead of the usual NSObject.

fn retainCount(&self) -> usize

where Self: Sized + Message,

The reference count of the object.

impl PartialEq for UIFocusGuide

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl RefEncode for UIFocusGuide

const ENCODING_REF: Encoding = <UILayoutGuide as ::objc2::RefEncode>::ENCODING_REF

The Objective-C type-encoding for a reference of this type.

impl DowncastTarget for UIFocusGuide

impl Eq for UIFocusGuide