QtScxml 状态机中的事件处理

Question

我正在尝试使用 QScxmlStateMachine 对象，但不幸的是，当我的 transition 的 cond 属性被填充时，我无法触发事件，无论如何值。

machine.scxml:

<?xml version="1.0" encoding="UTF-8"?>
<scxml xmlns="http://www.w3.org/2005/07/scxml" version="1.0" binding="early" name="Machine" qt:editorversion="4.8.0" xmlns:qt="http://www.qt.io/2015/02/scxml-ext">
    <state id="state1">
        <qt:editorinfo scenegeometry="351.24;371.78;291.24;321.78;120;100" geometry="351.24;371.78;-60;-50;120;100"/>
        <transition type="external" event="event1" target="state2" cond="_event.data.dt === 'blah'"/>
    </state>
    <state id="state2">
        <qt:editorinfo scenegeometry="614.16;371.78;554.16;321.78;120;100" geometry="614.16;371.78;-60;-50;120;100"/>
    </state>
</scxml>

main.cpp:

#include <QApplication>

#include "machine.h"

using namespace std;

void displayActiveStates(Machine &machine);
void connectToState(Machine &machine, const QString &state);

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    Machine machine;
    machine.start();

    connectToState(machine, "state1");
    connectToState(machine, "state2");

    machine.submitEvent("event1", QVariantMap({
        {"dt", "blah"}
    }));

    return a.exec();
}

void displayActiveStates(Machine &machine) {
    for (auto state : machine.activeStateNames()) {
        qDebug(state.toLatin1());
    }
}

void connectToState(Machine &machine, const QString &state) {
    machine.connectToState(state, &machine, [&machine](bool active) {
        displayActiveStates(machine);
        qDebug(active ? "active" : "inactive");
    });
}

test_scxml.pro:

#-------------------------------------------------
#
# Project created by QtCreator 2018-12-17T16:28:49
#
#-------------------------------------------------

QT       += core gui scxml

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = test_scxml
TEMPLATE = app

# The following define makes your compiler emit warnings if you use
# any feature of Qt which has been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

CONFIG += c++11

SOURCES += \
        main.cpp

HEADERS +=

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

STATECHARTS += \
    machine.scxml

当我删除这个属性时，一切正常。

有什么想法吗？

Answer 1

如果 docs 被审核：

Data Models

Qt SCXML supports the null data model, which must be supported by conforming SCXML processors, and the ECMAScript data model. In addition, Qt SCXML provices its own C++ data model that is implemented by the QScxmlCppDataModel class. The class enables writing C++ code for expr attributes and elements. The data part of the data model is backed by a subclass of QScxmlCppDataModel, for which the Qt SCXML compiler will generate the dispatch methods.

您需要添加 datamodel="ecmascript" 属性：

<?xml version="1.0" encoding="UTF-8"?>
<scxml xmlns="http://www.w3.org/2005/07/scxml" version="1.0" binding="early" name="Machine" qt:editorversion="4.8.0" xmlns:qt="http://www.qt.io/2015/02/scxml-ext" datamodel="ecmascript">
    <state id="state1">
        <qt:editorinfo scenegeometry="351.24;371.78;291.24;321.78;120;100" geometry="351.24;371.78;-60;-50;120;100"/>
        <transition type="external" event="event1" target="state2" cond="_event.data.dt === 'blah'"/>
    </state>
    <state id="state2">
        <qt:editorinfo scenegeometry="614.16;371.78;554.16;321.78;120;100" geometry="614.16;371.78;-60;-50;120;100"/>
    </state>
</scxml>

QtScxml 状态机中的事件处理

Events handling in QtScxml state machine

c++

qt

scxml

qt5