QApplication

QApplication is the root object for the entire application. It manages app level settings.

This class is a JS wrapper around Qt's QApplication class

The QApplication class manages the GUI application's control flow and main settings. In NodeGui you will never create an instance of it manually. NodeGui's internal runtime Qode does it for you on app start. You can access the initialised QApplication though if needed.

Example

const { QApplication } = require("@nodegui/nodegui");

const qApp = QApplication.instance();

qApp.quit();

Hierarchy

↳ NodeObject‹QApplicationSignals›

↳ QApplication

Index

Constructors

• constructor

Properties

• native
• nodeChildren
• nodeParent

Methods

• addEventListener
• devicePixelRatio
• dumpObjectInfo
• dumpObjectTree
• eventProcessed
• exec
• exit
• inherits
• objectName
• palette
• processEvents
• property
• quit
• quitOnLastWindowClosed
• removeEventListener
• setEventProcessed
• setNodeParent
• setObjectName
• setParent
• setProperty
• setQuitOnLastWindowClosed
• setStyleSheet
• clipboard
• instance
• primaryScreen
• screens
• setStyle
• style

Constructors

constructor

+ new QApplication(): QApplication

Overrides EventWidget.constructor

Returns: QApplication

+ new QApplication(native: NativeElement): QApplication

Overrides EventWidget.constructor

Parameters:

Name	Type
native	NativeElement

Returns: QApplication

Properties

native

• native: NativeElement

Overrides Component.native

---

nodeChildren

• nodeChildren: Set‹Component›

Inherited from Component.nodeChildren

---

Optional nodeParent

• nodeParent? : Component

Inherited from Component.nodeParent

Methods

addEventListener

▸ addEventListener‹SignalType›(signalType: SignalType, callback: QApplicationSignals[SignalType]): void

Inherited from EventWidget.addEventListener

Type parameters:

▪ SignalType: keyof QApplicationSignals

Parameters:

Name	Type	Description
signalType	SignalType	SignalType is a signal from the widgets signals interface.
callback	QApplicationSignals[SignalType]	Corresponding callback for the signal as mentioned in the widget's signal interface

Returns: void

void

For example in the case of QPushButton:

const button = new QPushButton();

button.addEventListener('clicked',(checked)=>console.log("clicked"));

// here clicked is a value from QPushButtonSignals interface

▸ addEventListener(eventType: WidgetEventTypes, callback: function): void

Inherited from EventWidget.addEventListener

Parameters:

▪ eventType: WidgetEventTypes

▪ callback: function

For example in the case of QPushButton:

const button = new QPushButton();

button.addEventListener(WidgetEventTypes.HoverEnter,()=>console.log("hovered"));

▸ (event?: NativeRawPointer‹"QEvent"›): void

Parameters:

Name	Type
event?	NativeRawPointer‹"QEvent"›

Returns: void

---

devicePixelRatio

▸ devicePixelRatio(): number

Returns: number

---

dumpObjectInfo

▸ dumpObjectInfo(): void

Inherited from NodeObject.dumpObjectInfo

Returns: void

---

dumpObjectTree

▸ dumpObjectTree(): void

Inherited from NodeObject.dumpObjectTree

Returns: void

---

eventProcessed

▸ eventProcessed(): boolean

Inherited from EventWidget.eventProcessed

Get the state of the event processed flag

See setEventProcessed().

Returns: boolean

boolean True if the current event is flagged as processed.

---

exec

▸ exec(): number

Returns: number

---

exit

▸ exit(exitCode: number): number

Parameters:

Name	Type
exitCode	number

Returns: number

---

inherits

▸ inherits(className: string): boolean

Inherited from NodeObject.inherits

Parameters:

Name	Type
className	string

Returns: boolean

---

objectName

▸ objectName(): string

Inherited from NodeObject.objectName

Returns: string

---

palette

▸ palette(): QPalette

Returns: QPalette

---

processEvents

▸ processEvents(): void

Returns: void

---

property

▸ property(name: string): QVariant

Inherited from NodeObject.property

Parameters:

Name	Type
name	string

Returns: QVariant

---

quit

▸ quit(): number

Returns: number

---

quitOnLastWindowClosed

▸ quitOnLastWindowClosed(): boolean

Returns: boolean

---

removeEventListener

▸ removeEventListener‹SignalType›(signalType: SignalType, callback: QApplicationSignals[SignalType]): void

Inherited from EventWidget.removeEventListener

Type parameters:

▪ SignalType: keyof QApplicationSignals

Parameters:

Name	Type
signalType	SignalType
callback	QApplicationSignals[SignalType]

Returns: void

▸ removeEventListener(eventType: WidgetEventTypes, callback: function): void

Inherited from EventWidget.removeEventListener

Parameters:

▪ eventType: WidgetEventTypes

▪ callback: function

▸ (event?: NativeRawPointer‹"QEvent"›): void

Parameters:

Name	Type
event?	NativeRawPointer‹"QEvent"›

Returns: void

---

setEventProcessed

▸ setEventProcessed(isProcessed: boolean): void

Inherited from EventWidget.setEventProcessed

Mark the current event as having been processed

This method is used to indicate that the currently dispatched event has been processed and no further processing by superclasses is required. It only makes sense to call this method from an event handler.

When set, this flag will cause NodeGui's QObject::event() method to return true and not call the superclass event(), effectively preventing any further processing on this event.

Parameters:

Name	Type	Description
isProcessed	boolean	true if the event has been processed.

Returns: void

---

setNodeParent

▸ setNodeParent(parent?: Component): void

Inherited from Component.setNodeParent

Parameters:

Name	Type
parent?	Component

Returns: void

---

setObjectName

▸ setObjectName(objectName: string): void

Inherited from NodeObject.setObjectName

Parameters:

Name	Type
objectName	string

Returns: void

---

setParent

▸ setParent(parent: NodeObject‹QObjectSignals›): void

Inherited from NodeObject.setParent

Parameters:

Name	Type
parent	NodeObject‹QObjectSignals›

Returns: void

---

setProperty

▸ setProperty(name: string, value: QVariantType): boolean

Inherited from NodeObject.setProperty

Parameters:

Name	Type
name	string
value	QVariantType

Returns: boolean

---

setQuitOnLastWindowClosed

▸ setQuitOnLastWindowClosed(quit: boolean): void

Parameters:

Name	Type
quit	boolean

Returns: void

---

setStyleSheet

▸ setStyleSheet(styleSheet: string): void

Parameters:

Name	Type
styleSheet	string

Returns: void

---

Static clipboard

▸ clipboard(): QClipboard | null

Returns: QClipboard | null

---

Static instance

▸ instance(): QApplication

Returns: QApplication

---

Static primaryScreen

▸ primaryScreen(): QScreen | null

Returns: QScreen | null

---

Static screens

▸ screens(): QScreen[]

Returns: QScreen[]

---

Static setStyle

▸ setStyle(style: QStyle): void

Parameters:

Name	Type
style	QStyle

Returns: void

---

Static style

▸ style(): QStyle

Returns: QStyle