Struct gtk4::ConstantExpression

#[repr(transparent)]
pub struct ConstantExpression { /* private fields */ }

Implementations

impl ConstantExpression

pub fn for_value(value: &Value) -> ConstantExpression

pub fn value(&self) -> Value

impl ConstantExpression

pub fn upcast(self) -> Expression

pub fn upcast_ref(&self) -> &Expression

impl ConstantExpression

pub fn new<V: ToValue>(value: &V) -> Self

pub fn value_as<V: for<'b> FromValue<'b> + 'static>(&self) -> V

Similar to Self::value but panics if the value is of a different type.

Methods from Deref<Target = Expression>

pub const NONE: Option<&'static Expression> = None

pub fn bind(
    &self,
    target: &impl IsA<Object>,
    property: &str,
    this_: Option<&impl IsA<Object>>
) -> ExpressionWatch

pub fn value_type(&self) -> Type

pub fn is_static(&self) -> bool

pub fn watch<P: Fn() + 'static>(
    &self,
    this_: Option<&impl IsA<Object>>,
    notify: P
) -> ExpressionWatch

pub fn is<E: IsExpression>(&self) -> bool

pub fn downcast_ref<E: IsExpression>(&self) -> Option<&E>

pub fn type_(&self) -> Type

pub fn evaluate(&self, this: Option<&impl IsA<Object>>) -> Option<Value>

pub fn evaluate_as<V: for<'b> FromValue<'b> + 'static, T: IsA<Object>>(
    &self,
    this: Option<&T>
) -> Option<V>

Similar to Self::evaluate but panics if the value is of a different type.

pub fn chain_property<T: IsA<Object>>(
    &self,
    property_name: &str
) -> PropertyExpression

Create a PropertyExpression that looks up for property_name with self as parameter. This is useful in long chains of Expressions.

pub fn chain_closure<R>(&self, closure: RustClosure) -> ClosureExpression where
    R: ValueType, 

Create a ClosureExpression from a glib::Closure with self as the second parameter and R as the return type. The return type is checked at run-time and must always be specified. This is useful in long chains of Expressions when using the glib::closure! macro.

Note that the first parameter will always be the this object bound to the expression. If None is passed as this then the type of the first parameter must be Option<glib::Object> otherwise type checking will panic.

use gtk::prelude::*;
use gtk::glib;
use glib::{closure, Object};

let button = gtk::Button::new();
button.set_label("Hello");
let label = button
    .property_expression("label")
    .chain_closure::<String>(closure!(|_: Option<Object>, label: &str| {
        format!("{} World", label)
    }))
    .evaluate_as::<String, _>(gtk::Widget::NONE);
assert_eq!(label.unwrap(), "Hello World");

pub fn chain_closure_with_callback<F, R>(&self, f: F) -> ClosureExpression where
    F: Fn(&[Value]) -> R + 'static,
    R: ValueType, 

Create a ClosureExpression with self as the second parameter. This is useful in long chains of Expressions.

Trait Implementations

impl AsRef<Expression> for ConstantExpression

fn as_ref(&self) -> &Expression

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

impl Clone for ConstantExpression

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ConstantExpression

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

Formats the value using the given formatter.

impl Deref for ConstantExpression

type Target = Expression

The resulting type after dereferencing.

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

Dereferences the value.

impl Display for ConstantExpression

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

Formats the value using the given formatter.

impl<'a> FromValue<'a> for ConstantExpression

type Checker = GenericValueTypeOrNoneChecker<ConstantExpression>

Value type checker.

unsafe fn from_value(value: &'a Value) -> Self

Get the contained value from a Value.

impl StaticType for ConstantExpression

fn static_type() -> Type

Returns the type identifier of Self.

impl ToValue for ConstantExpression

fn to_value(&self) -> Value

Convert a value to a Value.

fn value_type(&self) -> Type

Returns the type identifer of self.

impl ToValueOptional for ConstantExpression

fn to_value_optional(s: Option<&Self>) -> Value

Convert an Option to a Value.

impl ValueType for ConstantExpression

type Type = ConstantExpression

Type to get the Type from.

impl IsExpression for ConstantExpression