---
name: robius-widget-patterns
description: |
  CRITICAL: Use for Robius widget patterns. Triggers on:
  apply_over, TextOrImage, modal, 可复用, 模态,
  collapsible, drag drop, reusable widget, widget design,
  pageflip, 组件设计, 组件模式
risk: critical
source: community
date_added: "2026-09-04"
---
## Supporting material availability

This catalog copy contains the inline guidance below, but does not include the following supporting paths. They are external prerequisites, not bundled files:

- `<support-root>/references/widget-patterns.md`
- `<support-root>/references/styling-patterns.md`
- `<support-root>/references/moly-widget-patterns.md`

Ask for the original supporting material or an existing installation before using a step that depends on these paths; this catalog does not identify a verified download source for them. Resolve each path relative to that installation, inspect its contents, and verify any applicable license and execution prerequisites. Do not run a command or claim a referenced procedure was followed until its required file exists. Do not fabricate the missing scripts or treat an unrelated file with the same name as equivalent. Independent steps fully documented here can proceed within the user’s authorized scope; report any dependent step as unavailable.


# Robius Widget Patterns Skill

Best practices for designing reusable Makepad widgets based on Robrix and Moly codebase patterns.

**Source codebases:**
- **Robrix**: Matrix chat client - Avatar, RoomsList, RoomScreen widgets
- **Moly**: AI chat application - Slot, ChatLine, PromptInput, AdaptiveView widgets

## When to Use
Use this skill when:
- Creating reusable Makepad widgets
- Designing widget component APIs
- Implementing text/image toggle patterns
- Dynamic styling in Makepad
- Keywords: robrix widget, makepad component, reusable widget, widget design pattern

## Production Patterns

For production-ready widget patterns, see the `_base/` directory:

| Pattern | Description |
|---------|-------------|
| 01-widget-extension | Add helper methods to widget references |
| 02-modal-overlay | Popups, dialogs using DrawList2d overlay |
| 03-collapsible | Expandable/collapsible sections |
| 04-list-template | Dynamic lists with LivePtr templates |
| 05-lru-view-cache | Memory-efficient view caching |
| 14-callout-tooltip | Tooltips with arrow positioning |
| 20-redraw-optimization | Efficient redraw patterns |
| 15-dock-studio-layout | IDE-style resizable panels |
| 16-hover-effect | Hover effects with instance variables |
| 17-row-based-grid-layout | Dynamic grid layouts |
| 18-drag-drop-reorder | Drag-and-drop widget reordering |
| 19-pageflip-optimization | PageFlip 切换优化，即刻销毁/缓存模式 |
| 21-collapsible-row-portal-list | Auto-grouping consecutive items in portal lists with FoldHeader |
| 22-dropdown-overlay | Dropdown popups using DrawList2d overlay (no layout push) |

## Standard Widget Structure

```rust
use makepad_widgets::*;

live_design! {
    use link::theme::*;
    use link::widgets::*;

    pub MyWidget = {{MyWidget}} {
        width: Fill, height: Fit,
        flow: Down,

        // Child widgets defined in DSL
        inner_view = <View> {
            // ...
        }
    }
}

#[derive(Live, LiveHook, Widget)]
pub struct MyWidget {
    #[deref] view: View,              // Delegate to inner View

    #[live] some_property: f64,       // DSL-configurable property
    #[live(100.0)] default_val: f64,  // With default value

    #[rust] internal_state: State,    // Rust-only state (not in DSL)

    #[animator] animator: Animator,   // For animations
}

impl Widget for MyWidget {
    fn handle_event(&mut self, cx: &mut Cx, event: &Event, scope: &mut Scope) {
        self.view.handle_event(cx, event, scope);
        // Custom event handling...
    }

    fn draw_walk(&mut self, cx: &mut Cx2d, scope: &mut Scope, walk: Walk) -> DrawStep {
        self.view.draw_walk(cx, scope, walk)
    }
}
```

## Text/Image Toggle Pattern

A common pattern for widgets that show either text or an image (like avatars):

```rust
live_design! {
    pub Avatar = {{Avatar}} {
        width: 36.0, height: 36.0,
        align: { x: 0.5, y: 0.5 }
        flow: Overlay,  // Stack views on top of each other

        text_view = <View> {
            visible: true,  // Default visible
            show_bg: true,
            draw_bg: {
                uniform background_color: #888888
                fn pixel(self) -> vec4 {
                    let sdf = Sdf2d::viewport(self.pos * self.rect_size);
                    let c = self.rect_size * 0.5;
                    sdf.circle(c.x, c.x, c.x)
                    sdf.fill_keep(self.background_color);
                    return sdf.result
                }
            }
            text = <Label> {
                text: "?"
            }
        }

        img_view = <View> {
            visible: false,  // Hidden by default
            img = <Image> {
                fit: Stretch,
                width: Fill, height: Fill,
            }
        }
    }
}

#[derive(LiveHook, Live, Widget)]
pub struct Avatar {
    #[deref] view: View,
    #[rust] info: Option<UserInfo>,
}

impl Avatar {
    /// Show text content, hiding the image
    pub fn show_text<T: AsRef<str>>(
        &mut self,
        cx: &mut Cx,
        bg_color: Option<Vec4>,
        info: Option<AvatarTextInfo>,
        username: T,
    ) {
        self.info = info.map(|i| i.into());

        // Get first character
        let first_char = utils::first_letter(username.as_ref())
            .unwrap_or("?").to_uppercase();
        self.label(ids!(text_view.text)).set_text(cx, &first_char);

        // Toggle visibility
        self.view(ids!(text_view)).set_visible(cx, true);
        self.view(ids!(img_view)).set_visible(cx, false);

        // Apply optional background color
        if let Some(color) = bg_color {
            self.view(ids!(text_view)).apply_over(cx, live! {
                draw_bg: { background_color: (color) }
            });
        }
    }

    /// Show image content, hiding the text
    pub fn show_image<F, E>(
        &mut self,
        cx: &mut Cx,
        info: Option<AvatarImageInfo>,
        image_set_fn: F,
    ) -> Result<(), E>
    where
        F: FnOnce(&mut Cx, ImageRef) -> Result<(), E>
    {
        let img_ref = self.image(ids!(img_view.img));
        let res = image_set_fn(cx, img_ref);

        if res.is_ok() {
            self.view(ids!(img_view)).set_visible(cx, true);
            self.view(ids!(text_view)).set_visible(cx, false);
            self.info = info.map(|i| i.into());
        }
        res
    }

    /// Check current display status
    pub fn status(&mut self) -> DisplayStatus {
        if self.view(ids!(img_view)).visible() {
            DisplayStatus::Image
        } else {
            DisplayStatus::Text
        }
    }
}
```

## Dynamic Styling with apply_over

Apply dynamic styles at runtime:

```rust
// Apply single property
self.view(ids!(content)).apply_over(cx, live! {
    draw_bg: { color: #ff0000 }
});

// Apply multiple properties
self.view(ids!(message)).apply_over(cx, live! {
    padding: { left: 20, right: 20 }
    margin: { top: 10 }
});

// Apply with variables
let highlight_color = if is_selected { vec4(1.0, 0.0, 0.0, 1.0) } else { vec4(0.5, 0.5, 0.5, 1.0) };
self.view(ids!(item)).apply_over(cx, live! {
    draw_bg: { color: (highlight_color) }
});
```

## Widget Reference Pattern

Implement `*Ref` methods for external API:

```rust
impl AvatarRef {
    /// See [`Avatar::show_text()`].
    pub fn show_text<T: AsRef<str>>(
        &self,
        cx: &mut Cx,
        bg_color: Option<Vec4>,
        info: Option<AvatarTextInfo>,
        username: T,
    ) {
        if let Some(mut inner) = self.borrow_mut() {
            inner.show_text(cx, bg_color, info, username);
        }
    }

    /// See [`Avatar::show_image()`].
    pub fn show_image<F, E>(
        &self,
        cx: &mut Cx,
        info: Option<AvatarImageInfo>,
        image_set_fn: F,
    ) -> Result<(), E>
    where
        F: FnOnce(&mut Cx, ImageRef) -> Result<(), E>
    {
        if let Some(mut inner) = self.borrow_mut() {
            inner.show_image(cx, info, image_set_fn)
        } else {
            Ok(())
        }
    }
}
```

## Collapsible/Expandable Pattern

```rust
live_design! {
    pub CollapsibleSection = {{CollapsibleSection}} {
        flow: Down,

        header = <View> {
            cursor: Hand,
            icon = <Icon> { }
            title = <Label> { text: "Section" }
        }

        content = <View> {
            visible: false,
            // Expandable content here
        }
    }
}

#[derive(Live, LiveHook, Widget)]
pub struct CollapsibleSection {
    #[deref] view: View,
    #[rust] is_expanded: bool,
}

impl CollapsibleSection {
    pub fn toggle(&mut self, cx: &mut Cx) {
        self.is_expanded = !self.is_expanded;
        self.view(ids!(content)).set_visible(cx, self.is_expanded);

        // Rotate icon
        let rotation = if self.is_expanded { 90.0 } else { 0.0 };
        self.view(ids!(header.icon)).apply_over(cx, live! {
            draw_icon: { rotation: (rotation) }
        });

        self.redraw(cx);
    }
}
```

## Loading State Pattern

```rust
live_design! {
    pub LoadableContent = {{LoadableContent}} {
        flow: Overlay,

        content = <View> {
            visible: true,
            // Main content
        }

        loading_overlay = <View> {
            visible: false,
            show_bg: true,
            draw_bg: { color: #00000088 }
            align: { x: 0.5, y: 0.5 }
            <BouncingDots> { }
        }

        error_view = <View> {
            visible: false,
            error_label = <Label> { }
        }
    }
}

#[derive(Live, LiveHook, Widget)]
pub struct LoadableContent {
    #[deref] view: View,
    #[rust] state: LoadingState,
}

pub enum LoadingState {
    Idle,
    Loading,
    Loaded,
    Error(String),
}

impl LoadableContent {
    pub fn set_state(&mut self, cx: &mut Cx, state: LoadingState) {
        self.state = state;
        match &self.state {
            LoadingState::Idle | LoadingState::Loaded => {
                self.view(ids!(content)).set_visible(cx, true);
                self.view(ids!(loading_overlay)).set_visible(cx, false);
                self.view(ids!(error_view)).set_visible(cx, false);
            }
            LoadingState::Loading => {
                self.view(ids!(content)).set_visible(cx, true);
                self.view(ids!(loading_overlay)).set_visible(cx, true);
                self.view(ids!(error_view)).set_visible(cx, false);
            }
            LoadingState::Error(msg) => {
                self.view(ids!(content)).set_visible(cx, false);
                self.view(ids!(loading_overlay)).set_visible(cx, false);
                self.view(ids!(error_view)).set_visible(cx, true);
                self.label(ids!(error_view.error_label)).set_text(cx, msg);
            }
        }
        self.redraw(cx);
    }
}
```

## PortalList Item Pattern

For virtual list items:

```rust
live_design! {
    pub ItemsList = {{ItemsList}} {
        list = <PortalList> {
            keep_invisible: false,
            auto_tail: false,
            width: Fill, height: Fill,
            flow: Down,

            // Item templates
            item_entry = <ItemEntry> {}
            header = <SectionHeader> {}
            empty = <View> {}
        }
    }
}

impl Widget for ItemsList {
    fn draw_walk(&mut self, cx: &mut Cx2d, scope: &mut Scope, walk: Walk) -> DrawStep {
        while let Some(item) = self.view.draw_walk(cx, scope, walk).step() {
            if let Some(mut list) = item.as_portal_list().borrow_mut() {
                list.set_item_range(cx, 0, self.items.len());

                while let Some(item_id) = list.next_visible_item(cx) {
                    let item = list.item(cx, item_id, live_id!(item_entry));
                    // Populate item with data
                    self.populate_item(cx, item, &self.items[item_id]);
                    item.draw_all(cx, scope);
                }
            }
        }
        DrawStep::done()
    }
}
```

## Best Practices

1. **Use `#[deref]` for delegation**: Delegate to inner View for standard behavior
2. **Separate DSL properties (`#[live]`) from Rust state (`#[rust]`)**
3. **Implement both inner methods and `*Ref` wrappers**
4. **Use `apply_over` for dynamic runtime styling**
5. **Use `flow: Overlay` for toggle/swap patterns**
6. **Use `set_visible()` to toggle between alternative views**
7. **Always call `redraw(cx)` after state changes**

## Reference Files

- `references/widget-patterns.md` - Additional widget patterns (Robrix)
- `references/styling-patterns.md` - Dynamic styling patterns (Robrix)
- `references/moly-widget-patterns.md` - Moly-specific patterns
  - `Slot` widget for runtime content replacement
  - `MolyRoot` conditional rendering wrapper
  - `AdaptiveView` for responsive Mobile/Desktop layouts
  - Chat line variants (UserLine, BotLine, ErrorLine, etc.)
  - `CommandTextInput` with action buttons
  - Sidebar navigation with radio buttons

## Limitations
- Use this skill only when the task clearly matches the scope described above.
- Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
- Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.