Qt QML State Machine Framework

Qt5.4introduced aQMLstate machine framework, withC + +similar to the state machine framework, you can create and execute a state diagram in your application. To this end,Qtqml.statemachinemodule provides a number of relevantQMLtype that is used to create an event-driven state machine, whichQMLThe types are listed below:

StateMachine -- state machine Butler, Execution algorithm is based on scxml ( state Chart XML Span style= "Font-family:dejavu Sans" > initialstate properties.

state--common types in the state machine, note theQtQuickin the module Statedifferent types, import the module firstQtQuickmodule, post-importQtqml.statemachinemodule.

finalstate-- As the name implies, using this state at the end of the state machine's work will trigger the state machine's finished () signal.

historystate-- is a pseudo state that records the last child state when exiting the parent state, at the beginning you can specify a default state.

signaltransition-- Toggles the state according to a specific signal.

timeouttransition-- Switch the status according to the timer.

The following is a comprehensive example:

qt5.4//Import the QtQuick module first, then import qtqml.statemachine module Imports QtQuick 2.4import qtquick.controls 1.2import qtqml.statemachine            1.0Item {width:400 height:200 Row {anchors.centerIn:parent spacing:10 Button { Id:startbutton text: "Start" onclicked: {//Start state machine if (!statemach            ine.running) {statemachine.running = True}}} Button { Id:button//state machine identification text:s11.active? "S11": S12.active? "S12": S13.active? "S13": "State"} button {Id:historybutton//history status record TEXT:STATEMACHINE.R Unning? S1.active?    "Interrupt": "Resume": "History"} Button {Id:quitbutton text: "Quit"} } statemachine {Id:statemachine initialstate:s1//Initial state//running:true//Running Property by button (St        Artbutton) settingsState {ID:S1 INITIALSTATE:S11//Initial status Signaltransition {targetstate:s                3//Toggle State signal:historyButton.clicked} Signaltransition according to signal { TARGETSTATE:S2//Toggle State signal:quitButton.clicked} Onentered:console according to signal. Log ("S1 entered") OnExited:console.log ("S1 exited") state {ID:S11 Sig               naltransition {targetstate:s12//toggle State signal:button.clicked based on signal            } onEntered:console.log ("S11 entered") OnExited:console.log ("S11 exited")} State {ID:S12 Signaltransition {//Toggle state targetstate According to signal: S13 signal:button.clicked} signaltransition {//override the signal of the parent state (qui        tbutton.clicked)           Signal:quitButton.clicked onTriggered:console.log ("Override-quitbutton clicked")             } onEntered:console.log ("S12 entered") OnExited:console.log ("S12 exited")} State {ID:S13 Signaltransition {//Toggle State TargetS based on signal                    Tate:s11 signal:button.clicked} timeouttransition {//switch state by timer Targetstate:s2 timeout:2000} onEntered:console.log ("                S13 entered ") OnExited:console.log (" S13 exited ")} historystate {//History state                Id:history}} state {ID:S3 signaltransition {//toggle State based on signal Targetstate:history signal:historyButton.clicked} onentered:console      . log ("S3 entered")      OnExited:console.log ("S3 exited")} finalstate {ID:S2} Onfinished:consol E.log ("state Finished")}}

Plus , state Span style= "Font-family:wenquanyi Micro Hei" >childmode property by default is a single-state mode, initially to set an initial state, we can also set the childmode for parallel mode, when entering the parent state, Will go into all the sub-states at the same time.

detailed information can be found below Qt Official documents:

Http://doc.qt.io/qt-5/qmlstatemachine.html

Qt QML State Machine Framework