Struct UICollectionLayoutListConfiguration

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pub struct UICollectionLayoutListConfiguration { /* private fields */ }

Available on crate feature UICollectionLayoutList only.

Expand description

A list configuration can be used to layout a section inside a UICollectionViewCompositionalLayout as a list.

Implementations§

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pub fn initWithAppearance( this: Allocated<Self>, appearance: UICollectionLayoutListAppearance, ) -> Retained<Self>

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pub fn appearance(&self) -> UICollectionLayoutListAppearance

The overall appearance of the section.

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pub fn showsSeparators(&self) -> bool

Whether this section shows separators or not. For additional control, see separatorConfiguration. Note that when this property is NO, the separatorConfiguration is ineffective.

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pub fn setShowsSeparators(&self, shows_separators: bool)

Setter for showsSeparators.

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pub fn separatorConfiguration(&self) -> Retained<UIListSeparatorConfiguration>

Available on crate feature UIListSeparatorConfiguration only.

The preferred configuration for separators. Used as a baseline for a section in a list using this UICollectionLayoutListConfiguration

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pub fn setSeparatorConfiguration( &self, separator_configuration: &UIListSeparatorConfiguration, )

Available on crate feature UIListSeparatorConfiguration only.

Setter for separatorConfiguration.

This is copied when set.

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pub unsafe fn itemSeparatorHandler( &self, ) -> UICollectionLayoutListItemSeparatorHandler

Available on crate features UIListSeparatorConfiguration and block2 only.

This handler is executed when the list section is configuring separator appearance for an item. The index path for the item being configured and a resolved separator configuration are passed in to this block. The configuration returned from this block will be treated as the final separator configuration for this item.

§Safety

The returned block’s argument 1 must be a valid pointer.
The returned block’s argument 2 must be a valid pointer.

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pub unsafe fn setItemSeparatorHandler( &self, item_separator_handler: UICollectionLayoutListItemSeparatorHandler, )

Available on crate features UIListSeparatorConfiguration and block2 only.

Setter for itemSeparatorHandler.

This is copied when set.

§Safety

item_separator_handler must be a valid pointer or null.

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pub fn backgroundColor(&self) -> Option<Retained<UIColor>>

Available on crate feature UIColor only.

The background color of the section. Defaults to nil, indicating the system background color for the specified appearance is used.

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pub fn setBackgroundColor(&self, background_color: Option<&UIColor>)

Available on crate feature UIColor only.

Setter for backgroundColor.

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pub unsafe fn leadingSwipeActionsConfigurationProvider( &self, ) -> UICollectionLayoutListSwipeActionsConfigurationProvider

Available on crate features UISwipeActionsConfiguration and block2 only.

Called when list is about to show leading swipe actions for a particular index path. Return either a UISwipeActionsConfiguration object or nil if this index path does not show swipe actions.

§Safety

The returned block’s argument must be a valid pointer.

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pub unsafe fn setLeadingSwipeActionsConfigurationProvider( &self, leading_swipe_actions_configuration_provider: UICollectionLayoutListSwipeActionsConfigurationProvider, )

Available on crate features UISwipeActionsConfiguration and block2 only.

Setter for leadingSwipeActionsConfigurationProvider.

This is copied when set.

§Safety

leading_swipe_actions_configuration_provider must be a valid pointer or null.

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pub unsafe fn trailingSwipeActionsConfigurationProvider( &self, ) -> UICollectionLayoutListSwipeActionsConfigurationProvider

Available on crate features UISwipeActionsConfiguration and block2 only.

Called when list is about to show trailing swipe actions for a particular index path. Return either a UISwipeActionsConfiguration object or nil if this index path does not show swipe actions.

§Safety

The returned block’s argument must be a valid pointer.

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pub unsafe fn setTrailingSwipeActionsConfigurationProvider( &self, trailing_swipe_actions_configuration_provider: UICollectionLayoutListSwipeActionsConfigurationProvider, )

Available on crate features UISwipeActionsConfiguration and block2 only.

Setter for trailingSwipeActionsConfigurationProvider.

This is copied when set.

§Safety

trailing_swipe_actions_configuration_provider must be a valid pointer or null.

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pub fn headerMode(&self) -> UICollectionLayoutListHeaderMode

Defines whether the section has a header. Defaults to UICollectionLayoutListHeaderModeNone.

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pub fn setHeaderMode(&self, header_mode: UICollectionLayoutListHeaderMode)

Setter for headerMode.

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pub fn footerMode(&self) -> UICollectionLayoutListFooterMode

Defines whether the section has a footer. Defaults to UICollectionLayoutListFooterModeNone.

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pub fn setFooterMode(&self, footer_mode: UICollectionLayoutListFooterMode)

Setter for footerMode.

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pub fn headerTopPadding(&self) -> CGFloat

Available on crate feature objc2-core-foundation only.

Padding above each section header. The default value is UICollectionViewLayoutAutomaticDimension

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pub fn setHeaderTopPadding(&self, header_top_padding: CGFloat)

Available on crate feature objc2-core-foundation only.

Setter for headerTopPadding.

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pub fn contentHuggingElements( &self, ) -> UICollectionLayoutListContentHuggingElements

Determines the type of items that will tightly hug their content.

The default value for this property is UICollectionLayoutListContentHuggingElementsSupplementaryHeader on visionOS for plain style table views and an empty set on all other platforms. When the value of this property is UICollectionLayoutListContentHuggingElementsSupplementaryHeader, the header view will not stretch the width of the collection view if its content’s intrinsic content size is less than the collection view’s width.

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pub fn setContentHuggingElements( &self, content_hugging_elements: UICollectionLayoutListContentHuggingElements, )

Setter for contentHuggingElements.

Methods from Deref<Target = NSObject>§

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

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>§

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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());

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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.

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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`
    }
}