makepad-event-action – skill Viết lách & Nội dung cho agent AI

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:

• ./references/event-system.md
• ./references/action-system.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.

Makepad Event/Action Skill

> Version: makepad-widgets (dev branch) | Last Updated: 2026-01-19

>

> Check for updates: https://crates.io/crates/makepad-widgets

You are an expert at Makepad event and action handling. Help users by:

• Handling events: Mouse, keyboard, touch, lifecycle events
• Creating actions: Widget-to-parent communication
• Event flow: Understanding event propagation

When to Use

• You need to handle input, lifecycle, or UI interaction events in Makepad.
• The task involves handle_event, Event variants, Hit processing, or widget action propagation.
• You need to design or debug Makepad event/action flow between widgets and parents.

Documentation

Refer to the local files for detailed documentation:

• ./references/event-system.md - Event enum and handling
• ./references/action-system.md - Action trait and patterns

IMPORTANT: Documentation Completeness Check

Before answering questions, Claude MUST:

1. Read the relevant reference file(s) listed above

2. If file read fails or file is empty:

• Report the missing reference and the resulting coverage limit; do not recommend an unavailable slash command or claim the missing procedure was followed
• Use independent inline patterns only after checking their compatibility with the project's pinned crate; identify unverified APIs

3. If reference file exists, incorporate its content into the answer

Event Enum (Key Variants)

pub enum Event {
    // Lifecycle
    Startup,
    Shutdown,
    Foreground,
    Background,
    Resume,
    Pause,

    // Drawing
    Draw(DrawEvent),
    LiveEdit,

    // Window
    WindowGotFocus(WindowId),
    WindowLostFocus(WindowId),
    WindowGeomChange(WindowGeomChangeEvent),
    WindowClosed(WindowClosedEvent),

    // Mouse
    MouseDown(MouseDownEvent),
    MouseMove(MouseMoveEvent),
    MouseUp(MouseUpEvent),
    Scroll(ScrollEvent),

    // Touch
    TouchUpdate(TouchUpdateEvent),

    // Keyboard
    KeyDown(KeyEvent),
    KeyUp(KeyEvent),
    TextInput(TextInputEvent),
    TextCopy(TextClipboardEvent),

    // Timer
    Timer(TimerEvent),
    NextFrame(NextFrameEvent),

    // Network
    HttpResponse(HttpResponse),

    // Widget Actions
    Actions(ActionsBuf),
}

Handling Events in Widgets

impl Widget for MyWidget {
    fn handle_event(&mut self, cx: &mut Cx, event: &Event, scope: &mut Scope) {
        // Check if event hits this widget's area
        match event.hits(cx, self.area()) {
            Hit::FingerDown(fe) => {
                // Mouse/touch down on this widget
                cx.action(MyWidgetAction::Pressed);
            }
            Hit::FingerUp(fe) => {
                if fe.is_over {
                    // Released while still over widget = click
                    cx.action(MyWidgetAction::Clicked);
                }
            }
            Hit::FingerHoverIn(_) => {
                self.animator_play(cx, id!(hover.on));
            }
            Hit::FingerHoverOut(_) => {
                self.animator_play(cx, id!(hover.off));
            }
            Hit::KeyDown(ke) => {
                if ke.key_code == KeyCode::Return {
                    cx.action(MyWidgetAction::Submitted);
                }
            }
            _ => {}
        }
    }
}

Hit Enum

pub enum Hit {
    // Finger/Mouse
    FingerDown(FingerDownEvent),
    FingerUp(FingerUpEvent),
    FingerMove(FingerMoveEvent),
    FingerHoverIn(FingerHoverEvent),
    FingerHoverOver(FingerHoverEvent),
    FingerHoverOut(FingerHoverEvent),
    FingerLongPress(FingerLongPressEvent),

    // Keyboard
    KeyDown(KeyEvent),
    KeyUp(KeyEvent),
    KeyFocus,
    KeyFocusLost,
    TextInput(TextInputEvent),
    TextCopy,

    // Nothing
    Nothing,
}

Action System

Defining Actions

#[derive(Clone, Debug, DefaultNone)]
pub enum ButtonAction {
    None,
    Clicked,
    Pressed,
    Released,
}

// DefaultNone derives Default returning None variant

Emitting Actions

// From main thread (in handle_event)
cx.action(ButtonAction::Clicked);

// From any thread (thread-safe)
Cx::post_action(MyAction::DataLoaded(data));

Handling Actions

fn handle_event(&mut self, cx: &mut Cx, event: &Event, scope: &mut Scope) {
    // Handle child widget actions
    let actions = cx.capture_actions(|cx| {
        self.button.handle_event(cx, event, scope);
    });

    // Check for specific action
    if self.button(id!(my_button)).clicked(&actions) {
        // Button was clicked
    }

    // Or iterate actions
    for action in actions.iter() {
        if let Some(ButtonAction::Clicked) = action.downcast_ref() {
            // Handle click
        }
    }
}

Widget Action Helpers

// Common widget action checks
impl ButtonRef {
    fn clicked(&self, actions: &ActionsBuf) -> bool;
    fn pressed(&self, actions: &ActionsBuf) -> bool;
    fn released(&self, actions: &ActionsBuf) -> bool;
}

impl TextInputRef {
    fn changed(&self, actions: &ActionsBuf) -> Option<String>;
    fn returned(&self, actions: &ActionsBuf) -> Option<String>;
}

Event Flow

1. Event arrives from platform layer

2. Root widget receives event first

3. Propagates down to children via handle_event

4. Widgets emit actions via cx.action()

5. Parent captures actions via cx.capture_actions()

6. App handles remaining actions

Timer and NextFrame

// Start a timer
let timer = cx.start_timer(1.0); // 1 second

// In handle_event
if let Event::Timer(te) = event {
    if te.timer_id == self.timer {
        // Timer fired
    }
}

// Request next frame callback
let next_frame = cx.new_next_frame();

// In handle_event
if let Event::NextFrame(ne) = event {
    if ne.frame_id == self.next_frame {
        // Next frame arrived
    }
}

When Answering Questions

1. Use event.hits(cx, area) to check if event targets a widget

2. Actions flow UP from child to parent (unlike events which flow DOWN)

3. Use cx.capture_actions() to intercept child actions

4. Cx::post_action() is thread-safe for async operations

5. DefaultNone derive macro auto-implements Default for enums

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.