Struct gio::ListModel[][src]

pub struct ListModel(_);
Expand description

ListModel is an interface that represents a mutable list of GObjects. Its main intention is as a model for various widgets in user interfaces, such as list views, but it can also be used as a convenient method of returning lists of data, with support for updates.

Each object in the list may also report changes in itself via some mechanism (normally the signal::glib::Object::notify signal). Taken together with the signal::ListModel::items-changed signal, this provides for a list that can change its membership, and in which the members can change their individual properties.

A good example would be the list of visible wireless network access points, where each access point can report dynamic properties such as signal strength.

It is important to note that the ListModel itself does not report changes to the individual items. It only reports changes to the list membership. If you want to observe changes to the objects themselves then you need to connect signals to the objects that you are interested in.

All items in a ListModel are of (or derived from) the same type. ListModelExt::item_type() returns that type. The type may be an interface, in which case all objects in the list must implement it.

The semantics are close to that of an array: ListModelExt::n_items() returns the number of items in the list and g_list_model_get_item() returns an item at a (0-based) position. In order to allow implementations to calculate the list length lazily, you can also iterate over items: starting from 0, repeatedly call g_list_model_get_item() until it returns None.

An implementation may create objects lazily, but must take care to return the same object for a given position until all references to it are gone.

On the other side, a consumer is expected only to hold references on objects that are currently “user visible”, in order to facilitate the maximum level of laziness in the implementation of the list and to reduce the required number of signal connections at a given time.

This interface is intended only to be used from a single thread. The thread in which it is appropriate to use it depends on the particular implementation, but typically it will be from the thread that owns the [thread-default main context][g-main-context-push-thread-default] in effect at the time that the model was created.

Implements

ListModelExt

Trait Implementations

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

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Feeds this value into the given Hasher. Read more

Feeds a slice of this type into the given Hasher. Read more

Override the virtual methods of this interface for the given subclass and do other interface initialization. Read more

Instance specific initialization. Read more

This method returns an Ordering between self and other. Read more

Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

Restrict a value to a certain interval. Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

Returns the type identifier of Self.

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Gets the TypeId of self. Read more

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Upcasts an object to a superclass or interface T. Read more

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Tries to downcast to a subclass or interface implementor T. Read more

Tries to downcast to a reference of its subclass or interface implementor T. Read more

Tries to cast to an object of type T. This handles upcasting, downcasting and casting between interface and interface implementors. All checks are performed at runtime, while downcast and upcast will do many checks at compile-time already. Read more

Tries to cast to reference to an object of type T. This handles upcasting, downcasting and casting between interface and interface implementors. All checks are performed at runtime, while downcast and upcast will do many checks at compile-time already. Read more

Casts to T unconditionally. Read more

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Performs the conversion.

Performs the conversion.

Returns true if the object is an instance of (can be cast to) T.

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Same as connect but takes a SignalId instead of a signal name.

Same as connect_local but takes a SignalId instead of a signal name.

Same as connect_unsafe but takes a SignalId instead of a signal name.

Emit signal by signal id.

Same as emit but takes Value for the arguments.

Emit signal by its name.

Same as emit_by_name but takes Value for the arguments.

Emit signal with details by signal id.

Same as emit_with_details but takes Value for the arguments.

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

🔬 This is a nightly-only experimental API. (toowned_clone_into)

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The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.