HardwareKeyboardDetector class

The HardwareKeyboardDetector component allows you to directly listen to events from a hardware keyboard, bypassing the Focus widget in Flutter. It will not listen for events from any on-screen (software) keyboards.

This component can be placed anywhere in the component tree. For example, it can be attached to the root level of the Game class, or to the player being controlled. Multiple HardwareKeyboardDetector components can coexist within the same game, and they all will receive the key events.

The component provides the onKeyEvent event handler, which can either be overridden or passed as a parameter in the constructor. This event handler fires whenever the user presses or releases any key on a keyboard, and also when a key is being held.

The stream of key events will be normalized by Flutter, meaning that for every KeyDownEvent there will always be the corresponding KeyUpEvent, possibly with some KeyRepeatEvents in the middle. Depending on the platform, some of these events may be "synthesized", i.e. created by the framework artificially in order to preserve the correct event sequence. See Flutter's HardwareKeyboard for more details.

Similar normalization guarantee exists when this component is added to or removed from the component tree. If the user was holding any keys when the HardwareKeyboardDetector was mounted, then artificial KeyDownEvents will be fired; if the user was holding keys when this component was removed, then KeyUpEvents will be synthesized.

Use pauseKeyEvents property to temporarily halt/resume the delivery of onKeyEvents. The events will also stop being delivered when the component is removed from the component tree.

Inheritance

• Object
• Component
• HardwareKeyboardDetector

Constructors

HardwareKeyboardDetector({void onKeyEvent(KeyEvent)?})

Properties

children → ComponentSet

The children components of this component.

no setter, inherited

debugColor ↔ Color

The color that the debug output should be rendered with.

getter/setter pair, inherited

debugCoordinatesPrecision ↔ int?

How many decimal digits to print when displaying coordinates in the debug mode. Setting this to null will suppress all coordinates from the output.

getter/setter pair, inherited

debugMode ↔ bool

Returns whether this Component is in debug mode or not. When a child is added to the Component it gets the same debugMode as its parent has when it is prepared.

getter/setter pair, inherited

debugPaint → Paint

The debugColor represented as a Paint object.

no setter, inherited

debugTextPaint → TextPaint

Returns a TextPaint object with the debugColor set as color for the text.

no setter, inherited

hasChildren → bool

no setter, inherited

hashCode → int

The hash code for this object.

no setter, inherited

isAltPressed → bool

True if the Alt key is currently being pressed.

no setter

isCapsLockOn → bool

True if Caps Lock currently turned on.

no setter

isControlPressed → bool

True if the Ctrl key is currently being pressed.

no setter

isLoaded → bool

Whether this component has completed its onLoad step.

no setter, inherited

isLoading → bool

Whether the component is currently executing its onLoad step.

no setter, inherited

isMounted → bool

Whether this component is currently added to a component tree.

no setter, inherited

isMounting → bool

no setter, inherited

isNumLockOn → bool

True if Num Lock currently turned on.

no setter

isRemoved → bool

Whether the component has been removed. Originally this flag is false, but it becomes true after the component was mounted and then removed from its parent. The flag becomes false again when the component is mounted to a new parent.

no setter, inherited

isRemoving → bool

Whether the component is scheduled to be removed.

no setter, inherited

isScrollLockOn → bool

True if Scroll Lock currently turned on.

no setter

isShiftPressed → bool

True if the Shift key is currently being pressed.

no setter

key → ComponentKey?

A key that can be used to identify this component in the tree.

final, inherited

loaded → Future<void>

A future that completes when this component finishes loading.

no setter, inherited

logicalKeysPressed → Set<LogicalKeyboardKey>

The set of logical keys that are currently being pressed on the keyboard. This set corresponds to the physicalKeysPressed list, and can be used to search for keys in a keyboard-layout-independent way.

no setter

mounted → Future<void>

A future that will complete once the component is mounted on its parent.

no setter, inherited

parent ↔ Component?

Who owns this component in the component tree.

getter/setter pair, inherited

pauseKeyEvents ↔ bool

When true, delivery of key events will be suspended.

getter/setter pair

physicalKeysPressed → List<PhysicalKeyboardKey>

The list of keys that are currently being pressed on the keyboard (or a keyboard-like device). The keys are listed in the order in which they were pressed, except for the modifier keys which may be listed out-of-order on some systems.

no setter

priority ↔ int

Render priority of this component. This allows you to control the order in which your components are rendered.

getter/setter pair, inherited

removed → Future<void>

A future that completes when this component is removed from its parent.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

add(Component component) → FutureOr<void>

Schedules component to be added as a child to this component.

inherited

addAll(Iterable<Component> components) → Future<void>

A convenience method to add multiple children at once.

inherited

addToParent(Component parent) → FutureOr<void>

Adds this component as a child of parent (see add for details).

inherited

ancestors({bool includeSelf = false}) → Iterable<Component>

An iterator producing this component's parent, then its parent's parent, then the great-grand-parent, and so on, until it reaches a component without a parent.

inherited

componentsAtLocation<T>(T locationContext, List<T>? nestedContexts, T? transformContext(CoordinateTransform, T), bool checkContains(Component, T)) → Iterable<Component>

This is a generic implementation of componentsAtPoint; refer to those docs for context.

inherited

componentsAtPoint(Vector2 point, [List<Vector2>? nestedPoints]) → Iterable<Component>

An iterable of descendant components intersecting the given point. The point is in the local coordinate space.

inherited

contains(Component c) → bool

Whether the children list contains the given component.

inherited

containsLocalPoint(Vector2 point) → bool

Checks whether the point is within this component's bounds.

inherited

containsPoint(Vector2 point) → bool

Same as containsLocalPoint, but for a "global" point.

inherited

createComponentSet() → ComponentSet

This method creates the children container for the current component. Override this method if you need to have a custom ComponentSet within a particular class.

inherited

descendants({bool includeSelf = false, bool reversed = false}) → Iterable<Component>

Recursively enumerates all nested children.

inherited

findGame() → FlameGame<World>?

Fetches the nearest FlameGame ancestor to the component.

inherited

findParent<T extends Component>({bool includeSelf = false}) → T?

Returns the closest parent further up the hierarchy that satisfies type=T, or null if no such parent can be found.

inherited

findRootGame() → FlameGame<World>?

Fetches the root FlameGame ancestor to the component.

inherited

firstChild<T extends Component>() → T?

Returns the first child that matches the given type T, or null if there are no such children.

inherited

handleLifecycleEventAdd(Component parent) → LifecycleEventStatus

inherited

handleLifecycleEventMove(Component newParent) → LifecycleEventStatus

inherited

handleLifecycleEventRemove(Component parent) → LifecycleEventStatus

inherited

handleResize(Vector2 size) → void

inherited

lastChild<T extends Component>() → T?

Returns the last child that matches the given type T, or null if there are no such children.

inherited

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

onChildrenChanged(Component child, ChildrenChangeType type) → void

This method will be invoked from lifecycle if child has been added to or removed from its parent children list.

inherited

onGameResize(Vector2 size) → void

Called whenever the size of the top-level Canvas changes.

inherited

onKeyEvent(KeyEvent event) → void

Override this event handler if you want to get notified whenever any key on a keyboard is pressed, held, or released. The event will be one of KeyDownEvent, KeyRepeatEvent, or KeyUpEvent, respectively.

onLoad() → FutureOr<void>

Late initialization method for Component.

inherited

onMount() → void

Called when the component is added to its parent.

override

onParentResize(Vector2 maxSize) → void

Called whenever the parent of this component changes size; and also once before onMount.

inherited

onRemove() → void

Called right before the component is removed from the game.

override

propagateToChildren<T extends Component>(bool handler(T), {bool includeSelf = false}) → bool

This method first calls the passed handler on the leaves in the tree, the children without any children of their own. Then it continues through all other children. The propagation continues until the handler returns false, which means "do not continue", or when the handler has been called with all children.

inherited

remove(Component component) → void

Removes a component from the component tree.

inherited

removeAll(Iterable<Component> components) → void

Removes all the children in the list and calls onRemove for all of them and their children.

inherited

removeFromParent() → void

Remove the component from its parent in the next tick.

inherited

removeWhere(bool test(Component component)) → void

Removes all the children for which the test function returns true.

inherited

render(Canvas canvas) → void

inherited

renderDebugMode(Canvas canvas) → void

inherited

renderTree(Canvas canvas) → void

inherited

setLoaded() → void

Used by the FlameGame to set the loaded state of the component, since the game isn't going through the whole normal component life cycle.

inherited

setMounted() → void

Used by the FlameGame to set the mounted state of the component, since the game isn't going through the whole normal component life cycle.

inherited

setRemoved() → void

Used by the FlameGame to set the removed state of the component, since the game isn't going through the whole normal component life cycle.

inherited

toString() → String

A string representation of this object.

inherited

update(double dt) → void

This method is called periodically by the game engine to request that your component updates itself.

inherited

updateTree(double dt) → void

This method traverses the component tree and calls update on all its children according to their priority order, relative to the priority of the direct siblings, not the children or the ancestors.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited