Sergio's questions

我刚刚开始使用 Qt Quick 但遇到了一个问题。有一堂课

class CanHandler : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QStringList plugins READ plugins NOTIFY pluginsChanged)
    Q_PROPERTY(QStringList interfaceNames READ interfaceNames NOTIFY interfacesChanged)
    Q_PROPERTY(QString selectedPlugin READ selectedPlugin WRITE setSelectedPlugin NOTIFY selectedPluginChanged)
public:
    explicit CanHandler(QObject *parent = nullptr);

    QStringList plugins() const { return m_plugins; }
    QStringList interfaceNames() const { return m_interfaceNames; }
    QString selectedPlugin() const { return m_selectedPlugin; }

signals:
    void pluginsChanged();
    void interfacesChanged();
    void selectedPluginChanged();

public slots:
    void setSelectedPlugin(const QString &pluginName)
    {
        if (pluginName == m_selectedPlugin)
            return;

        m_selectedPlugin = pluginName;
        updateInterfaceNames();
        emit selectedPluginChanged();
    }

private:
    QStringList m_plugins;
    QList<QCanBusDeviceInfo> m_interfaces;
    QStringList m_interfaceNames; // Store names for QML access
    QString m_selectedPlugin;

    void updateInterfaceNames() {
        m_interfaceNames.clear();
        if (!m_selectedPlugin.isEmpty()) {
            m_interfaces = QCanBus::instance()->availableDevices(m_selectedPlugin);
            for (const auto &info : m_interfaces) {
                m_interfaceNames.append(info.name());
            }
        }

        emit interfacesChanged();
    }
};

有CanPluginComboBox.qml

ComboBox {
    id: pluginComboBox
    property var can: null
    model: can ? can.plugins : []
    Component.onCompleted: {
        // Initialize currentIndex based on selectedPlugin
        if (can && can.plugins.contains(can.selectedPlugin)) {
            currentIndex = can.plugins.indexOf(can.selectedPlugin);
        } else if (can && can.plugins.length > 0) {
            currentIndex = 0;
        }
    }
    onActivated: can.setSelectedPlugin(currentText)

    Connections {
        target: can
        ignoreUnknownSignals: true

        onSelectedPluginChanged: {
            if (can && can.plugins.contains(can.selectedPlugin)) {
                currentIndex = can.plugins.indexOf(can.selectedPlugin);
            }
        }
    }
}

有 SettingsPageForm.ui.qml

Page {
    width: 1024
    height: 700

    title: qsTr("Settings")

    Label {
        text: qsTr("You are on Page 2.")
        anchors.centerIn: parent
    }

    CanPluginComboBox {
        // Use the custom component
        id: plugin_ComboBox
        can: can0
        width: 170
    }

    ComboBox {
        id: comboBox_canInterface
        x: 317
        y: 65
        width: 128
        model: can0.interfaceNames
    }
}

在 main.qml 中：

CanHandler {
   id: can0
}

问题出在can.plugins.contains(can.selectedPlugin)) 我收到的错误行中：

TypeError：对象 passthrucan、peakcan、socketcan、tinycan、virtualcan 的属性“contains”不是函数

console.log("can.plugins =", can.plugins)

输出一个数组 qml: can.plugins = [passthrucan,peakcan,socketcan,tinycan,virtualcan] 但数组检查失败

if (Array.isArray(can.plugins)) {
    console.log("can.plugins is array")
} else {
    console.error("can.plugins is not array!")
}

有一块搭载有 Ubuntu 18.04 的 ARM 板。默认情况下，启动在/etc/init.d/rcS 中注册的Qt demo。 UART（ttyS0）中有一个调试控制台。任务：在屏幕上启动标准控制台。或者以某种方式通过 ssh 在屏幕上启动控制台（这可能吗？）。如果您只是删除演示自动启动，屏幕上将不会出现任何内容。

更新。查看内核配置后，一切都变得清晰了： zcat /proc/config.gz | grep CONFIG_VT

CONFIG_VT=y
CONFIG_VT_CONSOLE=y
CONFIG_VT_CONSOLE_SLEEP=y
# CONFIG_VT_HW_CONSOLE_BINDING is not set

zcat /proc/config.gz | grep CONFIG_FRAMEBUFFER_CONSOLE

# CONFIG_FRAMEBUFFER_CONSOLE is not set

_rheos 向量中的 MCP 类对象的数量是事先不知道的。 std::vector我是第一次使用。请戳你的鼻子，怎么了。没有必要使用向量，但我没有找到动态对象数组的另一种解决方案。

class MCP
{
public:
    MCP (mbed::SPI& spi, PinName cs) : _spi(spi), _cs(cs) {}
private:
    mbed::SPI& _spi;
    mbed::DigitalOut _cs;
};

class Load
{
public:
    Load(uint8_t load_qty, mbed::SPI& spi, PinName rs) : _rs(rs)
    {
        for (register uint8_t i = 0; i < load_qty; i++)
        {
            _rheos.emplace_back(spi, NC);  //Здесь всё падает
        }
    }

private:
    mbed::DigitalOut _rs;
    std::vector<MCP> _rheos;
};

int main()
{
    mbed::SPI spi1(MOSI, MISO, SCK);
    Loads RLoads(7, spi1, BUTTON1); 
}

编译成功，但不起作用。