State Access

The layout! macro expands XML into Rust code that runs inside a &self method (typically view). Attribute values and text content that reference application state are automatically resolved against self.

Field and Method Attributes

Attributes that accept state — such as value on <text-input> or is-checked on <checkbox> — are written as bare field or method paths. The macro prefixes them with self. automatically.

<text-input placeholder="Search…" value="query" />

Expands to:

iced::widget::text_input("Search…", &self.query)

Dot-separated paths and method calls are also supported:

<text-input placeholder="Name" value="user.name" />
<checkbox is-checked="form.is_valid()" on-toggle="toggle_valid" />

Expand to:

iced::widget::text_input("Name", &self.user.name)
iced::widget::checkbox(self.form.is_valid())

Event Handler Attributes

Attributes that accept a handler — such as on-submit, on-press, on-input, on-toggle — accept two forms.

Message variant (contains ::)

If the value contains ::, it is emitted as-is:

<button on-press="Message::Clicked">…</button>

iced::widget::button(…).on_press(Message::Clicked)

Method name (no ::)

Otherwise the value is treated as a method on self. The exact wrapping depends on the handler:

Attribute	Generated code
on-press, on-submit, on-press-maybe, on-submit-maybe	self.method()
on-press-with	|| self.method()
on-input, on-paste	|s| self.method(s)
on-toggle	|checked| self.method(checked)
on-change (vertical-slider)	|v| self.method(v)

Examples:

<text-input value="query" on-input="update_query" on-submit="submit" />

iced::widget::text_input("", &self.query)
    .on_input(|s| self.update_query(s))
    .on_submit(self.submit())

<checkbox is-checked="checked" on-toggle="toggle" />

iced::widget::checkbox(self.checked)
    .on_toggle(|checked| self.toggle(checked))

Text Interpolation

Inside <text> content (and other text-bearing attributes such as label on <checkbox>), you can embed state values using ${…} syntax. Like attribute paths, the variable is resolved against self.

Single variable

When the entire content is a single ${…} expression, the macro passes a reference directly — no allocation:

<text>${username}</text>

iced::widget::text(&self.username)

Mixed content

When the content contains both literal text and variables, the macro generates a format! call:

<text>Hello, ${username}! You have ${message_count} messages.</text>

iced::widget::text(format!("Hello, {}! You have {} messages.", self.username, self.message_count))