Struct UICollectionViewLayout 

pub struct UICollectionViewLayout { /* private fields */ }

Available on crate feature UICollectionViewLayout only.

Apple’s documentation

Implementations

impl UICollectionViewLayout

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

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

Safety

coder possibly has further requirements.

pub fn collectionView(&self) -> Option<Retained<UICollectionView>>

Available on crate features UICollectionView and UIResponder and UIScrollView and UIView only.

pub fn invalidateLayout(&self)

pub fn invalidateLayoutWithContext( &self, context: &UICollectionViewLayoutInvalidationContext, )

pub unsafe fn registerClass_forDecorationViewOfKind( &self, view_class: Option<&AnyClass>, element_kind: &NSString, )

Safety

view_class probably has further requirements.

pub fn registerNib_forDecorationViewOfKind( &self, nib: Option<&UINib>, element_kind: &NSString, )

👎Deprecated: Loading Interface Builder products will not be supported in a future version of visionOS.

Available on crate feature UINib only.

impl UICollectionViewLayout

Methods declared on superclass NSObject.

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

impl UICollectionViewLayout

UISubclassingHooks.

pub fn layoutAttributesClass(mtm: MainThreadMarker) -> &'static AnyClass

pub fn invalidationContextClass(mtm: MainThreadMarker) -> &'static AnyClass

pub fn prepareLayout(&self)

pub fn layoutAttributesForElementsInRect( &self, rect: CGRect, ) -> Option<Retained<NSArray<UICollectionViewLayoutAttributes>>>

Available on crate feature objc2-core-foundation only.

pub fn layoutAttributesForItemAtIndexPath( &self, index_path: &NSIndexPath, ) -> Option<Retained<UICollectionViewLayoutAttributes>>

pub fn layoutAttributesForSupplementaryViewOfKind_atIndexPath( &self, element_kind: &NSString, index_path: &NSIndexPath, ) -> Option<Retained<UICollectionViewLayoutAttributes>>

pub fn layoutAttributesForDecorationViewOfKind_atIndexPath( &self, element_kind: &NSString, index_path: &NSIndexPath, ) -> Option<Retained<UICollectionViewLayoutAttributes>>

pub fn shouldInvalidateLayoutForBoundsChange(&self, new_bounds: CGRect) -> bool

Available on crate feature objc2-core-foundation only.

pub fn invalidationContextForBoundsChange( &self, new_bounds: CGRect, ) -> Retained<UICollectionViewLayoutInvalidationContext>

Available on crate feature objc2-core-foundation only.

pub fn shouldInvalidateLayoutForPreferredLayoutAttributes_withOriginalAttributes( &self, preferred_attributes: &UICollectionViewLayoutAttributes, original_attributes: &UICollectionViewLayoutAttributes, ) -> bool

pub fn invalidationContextForPreferredLayoutAttributes_withOriginalAttributes( &self, preferred_attributes: &UICollectionViewLayoutAttributes, original_attributes: &UICollectionViewLayoutAttributes, ) -> Retained<UICollectionViewLayoutInvalidationContext>

pub fn targetContentOffsetForProposedContentOffset_withScrollingVelocity( &self, proposed_content_offset: CGPoint, velocity: CGPoint, ) -> CGPoint

Available on crate feature objc2-core-foundation only.

pub fn targetContentOffsetForProposedContentOffset( &self, proposed_content_offset: CGPoint, ) -> CGPoint

Available on crate feature objc2-core-foundation only.

pub fn collectionViewContentSize(&self) -> CGSize

Available on crate feature objc2-core-foundation only.

pub fn developmentLayoutDirection(&self) -> UIUserInterfaceLayoutDirection

Available on crate feature UIInterface only.

pub fn flipsHorizontallyInOppositeLayoutDirection(&self) -> bool

impl UICollectionViewLayout

UIUpdateSupportHooks.

pub fn prepareForCollectionViewUpdates( &self, update_items: &NSArray<UICollectionViewUpdateItem>, )

Available on crate feature UICollectionViewUpdateItem only.

pub fn finalizeCollectionViewUpdates(&self)

pub fn prepareForAnimatedBoundsChange(&self, old_bounds: CGRect)

Available on crate feature objc2-core-foundation only.

pub fn finalizeAnimatedBoundsChange(&self)

pub fn prepareForTransitionToLayout(&self, new_layout: &UICollectionViewLayout)

pub fn prepareForTransitionFromLayout( &self, old_layout: &UICollectionViewLayout, )

pub fn finalizeLayoutTransition(&self)

pub fn initialLayoutAttributesForAppearingItemAtIndexPath( &self, item_index_path: &NSIndexPath, ) -> Option<Retained<UICollectionViewLayoutAttributes>>

pub fn finalLayoutAttributesForDisappearingItemAtIndexPath( &self, item_index_path: &NSIndexPath, ) -> Option<Retained<UICollectionViewLayoutAttributes>>

pub fn initialLayoutAttributesForAppearingSupplementaryElementOfKind_atIndexPath( &self, element_kind: &NSString, element_index_path: &NSIndexPath, ) -> Option<Retained<UICollectionViewLayoutAttributes>>

pub fn finalLayoutAttributesForDisappearingSupplementaryElementOfKind_atIndexPath( &self, element_kind: &NSString, element_index_path: &NSIndexPath, ) -> Option<Retained<UICollectionViewLayoutAttributes>>

pub fn initialLayoutAttributesForAppearingDecorationElementOfKind_atIndexPath( &self, element_kind: &NSString, decoration_index_path: &NSIndexPath, ) -> Option<Retained<UICollectionViewLayoutAttributes>>

pub fn finalLayoutAttributesForDisappearingDecorationElementOfKind_atIndexPath( &self, element_kind: &NSString, decoration_index_path: &NSIndexPath, ) -> Option<Retained<UICollectionViewLayoutAttributes>>

pub fn indexPathsToDeleteForSupplementaryViewOfKind( &self, element_kind: &NSString, ) -> Retained<NSArray<NSIndexPath>>

pub fn indexPathsToDeleteForDecorationViewOfKind( &self, element_kind: &NSString, ) -> Retained<NSArray<NSIndexPath>>

pub fn indexPathsToInsertForSupplementaryViewOfKind( &self, element_kind: &NSString, ) -> Retained<NSArray<NSIndexPath>>

pub fn indexPathsToInsertForDecorationViewOfKind( &self, element_kind: &NSString, ) -> Retained<NSArray<NSIndexPath>>

impl UICollectionViewLayout

UIReorderingSupportHooks.

pub fn targetIndexPathForInteractivelyMovingItem_withPosition( &self, previous_index_path: &NSIndexPath, position: CGPoint, ) -> Retained<NSIndexPath>

Available on crate feature objc2-core-foundation only.

pub fn layoutAttributesForInteractivelyMovingItemAtIndexPath_withTargetPosition( &self, index_path: &NSIndexPath, position: CGPoint, ) -> Retained<UICollectionViewLayoutAttributes>

Available on crate feature objc2-core-foundation only.

pub fn invalidationContextForInteractivelyMovingItems_withTargetPosition_previousIndexPaths_previousPosition( &self, target_index_paths: &NSArray<NSIndexPath>, target_position: CGPoint, previous_index_paths: &NSArray<NSIndexPath>, previous_position: CGPoint, ) -> Retained<UICollectionViewLayoutInvalidationContext>

Available on crate feature objc2-core-foundation only.

pub fn invalidationContextForEndingInteractiveMovementOfItemsToFinalIndexPaths_previousIndexPaths_movementCancelled( &self, index_paths: &NSArray<NSIndexPath>, previous_index_paths: &NSArray<NSIndexPath>, movement_cancelled: bool, ) -> Retained<UICollectionViewLayoutInvalidationContext>

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 UICollectionViewLayout

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for UICollectionViewLayout

fn as_ref(&self) -> &NSObject

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

impl AsRef<UICollectionViewLayout> for UICollectionViewCompositionalLayout

Available on crate feature UICollectionViewCompositionalLayout only.

fn as_ref(&self) -> &UICollectionViewLayout

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

impl AsRef<UICollectionViewLayout> for UICollectionViewFlowLayout

Available on crate feature UICollectionViewFlowLayout only.

fn as_ref(&self) -> &UICollectionViewLayout

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

impl AsRef<UICollectionViewLayout> for UICollectionViewLayout

fn as_ref(&self) -> &Self

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

impl AsRef<UICollectionViewLayout> for UICollectionViewTransitionLayout

Available on crate feature UICollectionViewTransitionLayout only.

fn as_ref(&self) -> &UICollectionViewLayout

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

impl Borrow<AnyObject> for UICollectionViewLayout

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for UICollectionViewLayout

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl Borrow<UICollectionViewLayout> for UICollectionViewCompositionalLayout

Available on crate feature UICollectionViewCompositionalLayout only.

fn borrow(&self) -> &UICollectionViewLayout

Immutably borrows from an owned value.

impl Borrow<UICollectionViewLayout> for UICollectionViewFlowLayout

Available on crate feature UICollectionViewFlowLayout only.

fn borrow(&self) -> &UICollectionViewLayout

Immutably borrows from an owned value.

impl Borrow<UICollectionViewLayout> for UICollectionViewTransitionLayout

Available on crate feature UICollectionViewTransitionLayout only.

fn borrow(&self) -> &UICollectionViewLayout

Immutably borrows from an owned value.

impl ClassType for UICollectionViewLayout

const NAME: &'static str = "UICollectionViewLayout"

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

type Super = NSObject

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 UICollectionViewLayout

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

Formats the value using the given formatter.

impl Deref for UICollectionViewLayout

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for UICollectionViewLayout

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 UICollectionViewLayout

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSCoding for UICollectionViewLayout

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

where Self: Sized + Message,

Safety

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

where Self: Sized + Message,

Safety

impl NSObjectProtocol for UICollectionViewLayout

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 UICollectionViewLayout

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 UICollectionViewLayout

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

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

impl DowncastTarget for UICollectionViewLayout

impl Eq for UICollectionViewLayout