Event types

Every event type in Strata's API, with the interface its handlers receive. Input types are constants in InputEvents, the focus events are on Focusable, drawing and sizing are on Component, and each control's events are on the attribute or control that declares them. See Events for how delivery works. All positions in pointer events are in host coordinates, in UI units.

Pointer

Type	Interface	Bubbles	Fired at	When
POINTER_ENTER	PointerEvent	no	The newly hovered component	It became the deepest component under the pointer, including when it appears under a still pointer after a layout change, on the next pointer input
POINTER_EXIT	PointerEvent	no	The previously hovered component	It stopped being the deepest one, or the pointer left the host
POINTER_MOVE	PointerEvent	yes	The hovered component	The pointer moved, after any enter or exit for the same move
POINTER_PRESS	PointerButtonEvent	yes	The deepest component under the pointer	A button went down. Focus has already moved. A press that closed a popup fires nothing.
POINTER_RELEASE	PointerButtonEvent	yes	The component the press started on	That button came up, wherever the pointer is
CLICK	PointerButtonEvent	yes	The same	After the release, if the pointer is still over it, it is enabled, and no drag happened
DRAG_START	DragEvent	yes	The component the press started on	The pointer moved more than 4 units on either axis with the button held. Positions are the press's. A handler may call startTransfer to make the drag carry a payload.
DRAG	DragEvent	yes	The same	Every move after DRAG_START, wherever the pointer is
DRAG_END	DragEvent	yes	The same	The button came up. Replaces the CLICK.
DRAG_ENTER	TransferEvent	no	The deepest component under a drag that carries a transfer, or its nearest enabled ancestor	The drag moved onto it
DRAG_OVER	TransferEvent	yes	The same, then up the ancestors until a handler accepts or rejects	Every move of such a drag, after any DRAG_EXIT and DRAG_ENTER. A list accepts its own dragged rows, and an editable text box accepts text.
DRAG_EXIT	TransferEvent	no	The component the drag was over	The drag left it, the pointer left the host, or the drag ended
DROP	TransferEvent	yes	The component that accepted last	The button came up over it. The drop takes the event's effect unless a handler calls reject().
TRANSFER_DONE	TransferEvent	no	The source that started the transfer	The drag ended, after any DROP. Its effect is what the target took, empty for none; after MOVE the source removes what it gave away.
SCROLL	ScrollEvent	yes	The component under the pointer	A wheel or trackpad scrolled

Keyboard and focus

Type	Interface	Bubbles	Fired at	When
KEY	KeyEvent	yes	The focused component, or else the top dialog's content, or else the screen's content	A key went down, repeated or came up. If nothing consumes a press, the host tries the commands' shortcuts, a mnemonic, the context menu key and the default or cancel button, then closes the top overlay on Escape or moves focus on Tab (see Keyboard shortcuts).
CHAR	CharEvent	yes	The focused component only; dropped if none	A character was typed
FOCUS_GAINED	FocusEvent	no	The component gaining focus	After focus changed, after the old component's FOCUS_LOST and the FOCUS_ENTER events. A control that keeps focus on an inner part, such as a spinner, a table or a tree, fires it on itself after the part.
FOCUS_LOST	FocusEvent	no	The component losing focus	After focus changed
FOCUS_EXIT	FocusEvent	no	Each ancestor of the component that lost focus that is not an ancestor of the one that gained it, innermost first	After FOCUS_LOST. other() is the component that gained focus.
FOCUS_ENTER	FocusEvent	no	Each ancestor of the component that gained focus that is not an ancestor of the one that lost it, outermost first	After every FOCUS_EXIT and before FOCUS_GAINED. other() is the component that lost focus.
MODIFIERS_CHANGED	ModifiersEvent	no	The screen's content and each open overlay's content	The held modifiers changed, by a modifier key or by input arriving with different modifiers

FocusEvent.reason() says why focus moved: POINTER, KEYBOARD, CODE or ACTIVATION, the same on every event of one move; see Why focus moved. Both focus events fire on any component, panels included, and only on one with a handler for them. Component.isFocusWithin() tells whether the component or a descendant has focus.

Lifecycle

These reach only the component's own handlers, fire only when it has one, take no snapshots and do not bubble.

Type	Interface	When
Component.ATTACHED	LifecycleEvent	The component joined a tree a host is showing: it was added to an attached container or composite, its screen opened or was rebuilt, or its overlay opened. Every component of the subtree hears it, each parent before its children, once the subtree's bindings have set their properties. A kept component that joins again hears it again.
Component.DETACHED	LifecycleEvent	The component left a tree a host is showing: it or an ancestor was removed (an expander does this with its content when it collapses, and a navigation view with the page it stops showing), its overlay closed, or its screen closed or was rebuilt. Every component of the subtree hears it, each child before its parent, while it is still attached and before its bindings stop.

Drawing and sizing

These reach only the component's own handlers, fire only when it has one, and take no snapshots.

Type	Interface	Kind	When
Component.PAINT	PaintEvent.Pre	Pre	Before the component draws. Canceling it skips the component's background, border and content; its children still draw.
Component.PAINTED	PaintEvent	Post	After the component and its children have drawn
Component.MEASURED	MeasureEvent	Post	After the component measured its content; a handler may change the size it asks for

Control events by attribute

An attribute's events serve every control that has the attribute. Requests (RequestEvent, ValueRequestEvent) fire only for the user's actions and can be canceled. Reports (ControlEvent, ValueEvent) fire after every change, from the user or from code, unless the table says "user only". All of them bubble, and stop at the first composite above the control unless they come from content the composite holds.

Type	Interface	Value	Controls with it
Toggle.TOGGLE	ValueRequestEvent	Boolean, the state about to be set	CheckBox, RadioButton, ToggleSwitch, ToggleButton
Toggle.TOGGLED	ValueEvent	Boolean, the new state	The same
Ranged.CHANGE	ValueRequestEvent	Double, already in range and on a step	Slider, Spinner, ScrollBar; a ProgressBar never fires it
Ranged.CHANGED	ValueEvent	Double, the new value	The same, and ProgressBar
HasDate.PICK_DATE	ValueRequestEvent	LocalDate, or null when clearing	CalendarView, DatePicker, DateTimePicker
HasDate.DATE_PICKED	ValueEvent	LocalDate, null when empty	The same
HasTime.PICK_TIME	ValueRequestEvent	LocalTime, or null when clearing	TimePicker, DateTimePicker
HasTime.TIME_PICKED	ValueEvent	LocalTime, null when empty	The same
TextEntry.MODIFY	RequestEvent	none; the control still holds the old text	TextBox, TextArea, PasswordTextBox
TextEntry.MODIFIED	ValueEvent	Integer, the new length in code points	The same
TextEntry.CARET_MOVED	ValueEvent	TextEntry.Caret: the anchor and the caret now, and where they were as the previous value. Fires once for each input or call that moved them, after EDITED and MODIFIED, from the user or from code. A report only; there is no request.	The same
TextInput.EDIT	ValueRequestEvent	String, the whole text the edit would produce; never null	TextBox, TextArea
TextInput.EDITED	ValueEvent	String, the new text	The same
Selection.SELECT	ValueRequestEvent	Integer, the index about to be current, or -1	The controls below, except a RadioGroup, whose buttons ask through Toggle.TOGGLE
Selection.SELECTED	ValueEvent	Integer, the current index, or -1	ListView, TableView, TreeView, GridView, ComboBox, CycleButton, TabBar, MenuBar, NavigationView, RadioGroup
MultiSelection.SELECT_MANY	ValueRequestEvent	List<Integer>, the indexes about to be selected	ListView, TableView, TreeView, GridView, in MULTIPLE mode
MultiSelection.SELECTED_MANY	ValueEvent	List<Integer>, the selected indexes	ListView, TableView, TreeView, GridView
Activatable.ACTIVATE	ValueRequestEvent	Integer, the entry's index	ListView, TableView, TreeView, GridView, NavigationView
Activatable.ACTIVATED	ValueEvent	Integer, the entry's index; user only	The same
Openable.OPEN	RequestEvent	none	ComboBox, DropDownButton, DatePicker, TimePicker, DateTimePicker. open() from code asks nothing.
Openable.OPENED	ControlEvent	none	The same, and InfoBar, Menu and Flyout, which only code or another control opens
Closable.CLOSE	RequestEvent	none	Window and InfoBar when the user closes them, and every popup (Menu, Flyout, the lists of ComboBox and the pickers) before Escape or a press outside closes it. Canceling it keeps the popup open, and the key or press is used up. close() from code, choosing a menu item and a submenu closing with its parent ask nothing.
Closable.CLOSED	ControlEvent	none	Window, the controls with Openable, and Overlay
Validatable.VALIDATED	ValueEvent	Validation, the new validation, and the one before as the previous value; neither is null. A report only; there is no request.	TextBox, TextArea, PasswordTextBox, Spinner, Slider, ComboBox, CheckBox, DatePicker, TimePicker, DateTimePicker, ColorPicker
HasContextMenu.SHOW_CONTEXT_MENU	ValueRequestEvent	Popup, the menu about to open; a handler may cancel it or set another popup, and null opens nothing. Fires only for the user's actions.	Container and every control that has a tooltip
CellEditing.EDIT_CELL	ValueRequestEvent	The item about to be edited; a value a handler sets is ignored	ListView, TreeView, TableView, GridView, when they have a cell editor
CellEditing.CELL_EDITED	ValueEvent	The item the editor committed, and the item that was edited as the previous value. The control has not changed its items.	The same
ItemDragging.MOVE_ITEMS	ValueRequestEvent	ItemMove: the ascending indexes of the rows and the index they would go before. A handler may cancel it or rewrite the move; if none cancels, the list moves its items with setItems.	ListView

Control events by control

Type	Interface	Value
Button.PRESS	RequestEvent	none
Button.PRESSED	ControlEvent	none
CheckBox.CHANGE	ValueRequestEvent	CheckState the change would leave; fires before Toggle.TOGGLE
CheckBox.CHANGED	ValueEvent	CheckState, the new state
Slider.COMMITTED	ValueEvent	Double, the value once the user is done: on the release that ends a press or drag, after each key that changed it, and after a change from code while no press is under way. The previous value is the last committed one. Never fires while isAdjusting() is true.
TextBox.SUBMIT	RequestEvent	none; Enter or keypad Enter, not on repeat
TextBox.SUBMITTED	ValueEvent	String, the text, with previous() equal to it; user only
TextBox.COMPLETE	ValueRequestEvent	TextBox.Suggestion the user accepted; never null
TextBox.COMPLETED	ValueEvent	TextBox.Suggestion that was applied, with previous() equal to it; user only
PasswordTextBox.SUBMIT	RequestEvent	none; Enter or keypad Enter, not on repeat
PasswordTextBox.SUBMITTED	ControlEvent	none; read the box with withPassword; user only
PasswordTextBox.REVEAL	ValueRequestEvent	Boolean, true to show the text; null keeps the state
PasswordTextBox.REVEALED	ValueEvent	Boolean, true while the text shows
ColorPicker.PICK	ValueRequestEvent	Integer, the new ARGB color; never null
ColorPicker.PICKED	ValueEvent	Integer, the new ARGB color
CalendarView.BROWSE	ValueRequestEvent	YearMonth about to show
CalendarView.BROWSED	ValueEvent	YearMonth now shown
DateTimePicker.PICK	ValueRequestEvent	LocalDateTime, or null when clearing
DateTimePicker.PICKED	ValueEvent	LocalDateTime, null when empty
TableView.SORT	ValueRequestEvent	TableView.Sort about to apply
TableView.SORTED	ValueEvent	TableView.Sort now applied; only when the column or direction changed
TableView.SORT_MANY	ValueRequestEvent	List<TableView.Sort>, the order about to apply, first sort first; empty for the set order. Asked for a click with Shift on a title.
TableView.SORTED_MANY	ValueEvent	List<TableView.Sort>, the new order, and the one before as the previous value; fires before SORTED when the first sort changed too
TableView.RESIZE_COLUMN	ValueRequestEvent	TableView.ColumnWidth: the column and the width it is about to get, already within its limits. Asked on each move of a drag on a title's right edge, and for a double click there.
TableView.COLUMN_RESIZED	ValueEvent	TableView.ColumnWidth, the new width; the previous value has the old one. A width set from code fires nothing.
TableView.MOVE_COLUMN	ValueRequestEvent	TableView.ColumnMove: the column and the index in columns() it is about to have
TableView.COLUMN_MOVED	ValueEvent	TableView.ColumnMove, the new index; the previous value has the old one. Adding and removing columns from code fires nothing.
TreeView.EXPAND	ValueRequestEvent	TreeView.Expansion: the item and whether it is about to expand
TreeView.EXPANDED	ValueEvent	TreeView.Expansion: the item and its new state
GridView.CLICK	ValueRequestEvent	GridView.Click: the cell's index, its item, the button and the modifiers
GridView.CLICKED	ValueEvent	GridView.Click as the request ended; user only
Menu.CHOOSE	ValueRequestEvent	MenuEntry chosen, a MenuItem or CheckMenuItem
Menu.CHOSEN	ValueEvent	MenuEntry, once the menus closed and the action ran; user only
Expander.EXPAND	ValueRequestEvent	Boolean, true to show the content; null is ignored
Expander.EXPANDED	ValueEvent	Boolean, true when shown
NavigationView.EXPAND	ValueRequestEvent	Boolean, whether the pane over the content would be open
NavigationView.EXPANDED	ValueEvent	Boolean, whether the pane is open
NavigationView.EXPAND_ITEM	ValueRequestEvent	NavigationView.Expansion: the item and whether it would expand
NavigationView.ITEM_EXPANDED	ValueEvent	NavigationView.Expansion: the item and its new state
SplitPane.MOVE	ValueRequestEvent	Float, the fraction of the space the first side is about to get
SplitPane.MOVED	ValueEvent	Float, the new fraction
SplitPane.COLLAPSE	ValueRequestEvent	SplitPane.Side about to collapse, or null to restore the collapsed side. Asked for a double click on the divider, Enter while it has focus, and a drag on the divider of a collapsed pane.
SplitPane.COLLAPSED	ValueEvent	SplitPane.Side now collapsed, null when none is; fires for changes from code too
Window.RESIZE	ValueRequestEvent	Size the window is about to take, without the margin
Window.RESIZED	ValueEvent	Size, the new size; user only
Window.MAXIMIZE	ValueRequestEvent	Boolean, true to maximize and false to restore. Asked for the maximize button and a double click on the title bar.
Window.MAXIMIZED	ValueEvent	Boolean, the new state, from the user or from code
Window.COLLAPSE	ValueRequestEvent	Boolean, true to collapse to the title bar and false to expand. Asked for the collapse button.
Window.COLLAPSED	ValueEvent	Boolean, the new state, from the user or from code
MessageBox.ANSWER	ValueRequestEvent	MessageBox.Result, the answer. Results are records equal by their ids.
MessageBox.ANSWERED	ValueEvent	MessageBox.Result, once, before the overlay closes
ScrollPanel.SCROLLED	ValueEvent	ScrollPanel.State after the change; there is no request

Each constant's Javadoc says exactly when it fires, what a handler may set and how the control checks it. "User only" marks a report that code has no method to cause.

What the events carry

Interface	Methods
Event	target(), current(), cause(), origin(), stopPropagation(), isPropagationStopped()
Cancelable	Event, plus cancel(), isCancelled(), consume(), isHandled(). Every input event and every request is one.
SnapshotEvent	Cancelable, plus snapshot(), currentSnapshot() and snapshotOf(component), which returns an Optional. Every input event and every request is one; reports, paint and measure events have no snapshot methods.
LifecycleEvent	Event, with nothing more. ATTACHED and DETACHED carry it.
PointerEvent	x(), y(), localX(), localY(), modifiers(), pointerId() (0 for the mouse, a pen and the first touch) and pressure() (0 to 1; 1 for a mouse)
PointerButtonEvent	Pointer, plus button(), clicks() (1, 2 or 3)
DragEvent	Pointer, plus button(), clicks(), startX(), startY(), deltaX(), deltaY() and startTransfer(transfer, allowed), with a form that also takes a function that builds the drag image
TransferEvent	Pointer, plus transfer(), allowed(), source() (empty for a drag from another application), preferred() (from the modifiers), effect(), accept(effect), accept() and reject()
ScrollEvent	Pointer, plus scrollX() (positive toward the left), scrollY() (positive away from the user), kind() (a ScrollKind)
KeyEvent	key(), action(), modifiers(), is(key, required, policy), is(keyStroke) and shortcutModifier()
CharEvent	codePoint(), text(), modifiers()
FocusEvent	other(): an Optional of the component on the other side of the move
ModifiersEvent	modifiers(): the modifiers now held
RequestEvent<C>	Cancelable, plus control()
ValueRequestEvent<C, V>	Request, plus value() and setValue(value)
ControlEvent<C>	Event, plus control()
ValueEvent<C, V>	Control event, plus value() and previous()
PaintEvent	Event, plus painter() and bounds(). PaintEvent.Pre is also Cancelable.
MeasureEvent	Event, plus context(), availableWidth(), availableHeight(), width(), height(), setWidth(width), setHeight(height)

Default behavior of the built-ins

Type	Button	CheckBox	Slider	TextBox
POINTER_PRESS			Moves the value to the pointer on a left press and consumes it	Places the caret, or selects a word (2 clicks) or everything (3 clicks). Shift extends.
CLICK	Presses on a left click and consumes it	Toggles on a left click and consumes it
DRAG_START, DRAG_END			Consumes left-button drags
DRAG			Follows the pointer and consumes it	Extends the selection, by word if the press was a double click
KEY	Presses on Enter, keypad Enter or Space (PRESS only) and consumes it	Toggles on Enter, keypad Enter or Space (PRESS only) and consumes it	Moves on arrows, Page Up, Page Down, Home and End, and consumes them	Edits and moves the caret; consumes what it uses and every printable key without Control or Alt
CHAR				Inserts the character and consumes it
FOCUS_GAINED				Moves the caret to the end, or selects everything after setSelectAllOnFocus(true)

Label, Image, Avatar and the plain panels have no default behavior. The other controls document theirs in the controls guide: a ScrollPanel scrolls on SCROLL, unused keys and drags of its bar; a ListView selects on POINTER_PRESS, activates on a double press or Enter, and moves on keys; a ComboBox opens on CLICK and changes on keys; a DropDownButton opens on CLICK and on keys; a Flyout moves focus on Tab; an InfoBar's close button closes the bar on CLICK and on Enter or Space; a NavigationView picks items, expands them and opens its pane on CLICK, and moves its cursor on keys; a Window moves on drags of its title bar and closes on Escape; a TabBar selects on clicks and Left and Right; a ScrollBar pages on POINTER_PRESS on its track, follows drags of its thumb, and moves on SCROLL and, when made focusable, on keys. Each consumes what it acts on.

Anything not listed does nothing by default and is not consumed. Disabled controls do nothing.