SCXML Calculator

An application that implements the Calculator example presented in the SCXML Specification.

計算器 使用 Qt SCXML 去實現計算器範例 presented in the SCXML Specification.

The state machine is specified in the statemachine.scxml file and compiled into the CalculatorStateMachine class. The user interface is created using Qt Quick.

運行範例

要運行範例從 Qt Creator ，打開 Welcome 模式，然後選擇範例從 Examples 。更多信息，拜訪構建和運行範例 .

實例化狀態機

We make the generated CalculatorStateMachine class available to QML by declaring it as a QML type in the calculator-qml.h 文件：

struct CalculatorStateMachineRegistration
{
    Q_GADGET
    QML_FOREIGN(CalculatorStateMachine)
    QML_NAMED_ELEMENT(CalculatorStateMachine)
    QML_ADDED_IN_VERSION(1, 0)
};

We instantiate a CalculatorStateMachine and listen to the updateDisplay event. When it occurs, we change the text on the calculator display:

    CalculatorStateMachine {
        id: statemachine
        running: true
        EventConnection {
            events: ["updateDisplay"]
            onOccurred: (event)=> resultText.text = event.data.display
        }
    }

When users press the calculator buttons, the buttons submit events to the state machine:

        Button {
            id: resultButton
            x: 3 * width
            y: parent.height / 5
            textHeight: y - 2
            fontHeight: 0.4
            width: parent.width / 4
            height: y * 4
            color: pressed ? "#e0b91c" : "#face20"
            text: "="
            onClicked: statemachine.submitEvent("EQUALS")
        }

範例工程 @ code.qt.io