SignalTransition QML Type
The SignalTransition type provides a transition based on a Qt signal. More...
| Import Statement: | import QtQml.StateMachine 6.12 |
| Inherits: |
Properties
Detailed Description
SignalTransition is part of Qt State Machine QML API.
Example Usage
import QtQuick
import QtQml.StateMachine as DSM
Rectangle {
DSM.StateMachine {
id: stateMachine
initialState: state
running: true
DSM.State {
id: state
DSM.SignalTransition {
targetState: finalState
signal: button.clicked
guard: guardButton.checked
}
}
DSM.FinalState {
id: finalState
}
onFinished: Qt.quit()
}
Row {
spacing: 2
Button {
id: button
text: "Finish state"
}
Button {
id: guardButton
checkable: true
text: checked ? "Press to block the SignalTransition" : "Press to unblock the SignalTransition"
}
}
}See also StateMachine, FinalState, and TimeoutTransition.
Property Documentation
guard : bool
Guard conditions affect the behavior of a state machine by enabling transitions only when they evaluate to true and disabling them when they evaluate to false.
When the signal associated with this signal transition is emitted the guard condition is evaluated. In the guard condition the arguments of the signal can be used as demonstrated in the example below.
import QtQuick
import QtQml.StateMachine as DSM
Rectangle {
Button {
anchors.fill: parent
id: button
DSM.StateMachine {
DSM.State {
DSM.SignalTransition {
targetState: finalState
signal: button.mysignal
// the guard condition uses the mystr string argument from mysignal
guard: mystr == "test"
}
}
DSM.FinalState {
id: finalState
}
}
// define the signal the SignalTransition is connected with
signal mysignal(mystr: string)
// on clicking the button emit the signal with a single string argument
onClicked: button.mysignal("test")
}
}See also signal.
signal : signal
The signal which is associated with this signal transition.
import QtQuick
import QtQml.StateMachine as DSM
Rectangle {
Button {
anchors.fill: parent
id: button
DSM.StateMachine {
DSM.State {
DSM.SignalTransition {
targetState: finalState
signal: button.clicked
}
}
DSM.FinalState {
id: finalState
}
}
}
}© 2026 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.