SCXML Calculator

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

计算器 使用 Qt SCXML 去实现 计算器范例 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.

运行范例

要运行范例从 Qt Creator ，打开 Welcome 模式，然后选择范例从 Examples 。更多信息，拜访 构建和运行范例 .

实例化状态机

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")
        }
					

范例工程 @ code.qt.io

内容

• 运行范例

• 实例化状态机