# Signals and input

Signals communicate events and user intent without exposing component internals.
Property change signals communicate state changes, not necessarily user actions.

```qml
Item {
    id: root
    signal activated(string source)

    TapHandler {
        onTapped: root.activated("pointer")
    }
}
```

Use a handler on the emitting object when it owns the response.
Use `Connections` when another object or a replaceable target owns the response.

```qml
Connections {
    target: backend
    function onStatusChanged() {
        statusLabel.text = backend.status
    }
}
```

## User intent versus property changes

Choose user-only Control signals when writing state back to its owner:

```qml
Slider {
    value: settings.volume
    onMoved: settings.volume = value
}
```

`onValueChanged` also runs when the value changes programmatically and can create feedback writes.
The assignment to `settings.volume` does not break the binding on `Slider.value`.
An imperative assignment to `Slider.value` would replace that binding.

## Keyboard and focus

A `Keys` handler receives events only while its item has active focus.
Use Controls for standard keyboard behavior, `Shortcut` for shortcuts, and custom key handlers only for component-specific behavior.
Verify focus entry, traversal, activation, and exit rather than assuming pointer behavior covers keyboard interaction.

Custom interactive items must expose an appropriate `Accessible.role`, a meaningful `Accessible.name`, keyboard activation, and a visible focus state.