c++ - 来自 C++ 的 QStandardItemModel 在 QtQuick/QML TableView 中不可见

Question

我已经对 QStandardItemModel 进行了子类化，并希望将其与 QML 中的 TableView 链接起来。但是来自 QStandardItemModel 的数据在 TableView 中是不可见的。

在 tableview 中将角色设置为“显示”后，我可以看到第一列，因此我在我的类(class)中重新实现了 roleNames() 函数，但仍然没有成功。我不确定如何将 roleNames 枚举与 QStandardItemModel 中的列链接起来？

class AuditLogsModel : public QStandardItemModel
{
    Q_OBJECT
    QList<QStandardItem*> row;
public:
    enum AuditRoles
    {
        DateTimeRole = Qt::UserRole + 1,
        UsernameRole,
        ApplicationRole,
        CategoryRole,
        DescriptionRole
    };
...

Implementation (C++) source

AuditLogsModel::AuditLogsModel(QObject *parent)
    : QStandardItemModel(parent)
{
    row.clear();
    loadData();
    setColumnMapping();
}

void AuditLogsModel::setColumnMapping()
{
    setData(index(0,0), "DateTime", AuditRoles::DateTimeRole);
    setData(index(0,1), "Name", AuditRoles::UsernameRole);
    setData(index(0,2), "Application", AuditRoles::ApplicationRole);
    setData(index(0,3), "Category", AuditRoles::CategoryRole);
    setData(index(0,4), "Description", AuditRoles::DescriptionRole);
}

QHash<int, QByteArray> AuditLogsModel::roleNames() const
{
    QHash<int, QByteArray> roleNameMap;
    roleNameMap[DateTimeRole] = "DateTime";
    roleNameMap[UsernameRole] = "Name";
    roleNameMap[ApplicationRole] = "Application";
    roleNameMap[CategoryRole] = "Category";
    roleNameMap[DescriptionRole] = "Description";

    return roleNameMap;
}

void AuditLogsModel::loadData()
{
    QFile file(AUDIT_LOG_PATH);
    if( file.exists() == false )
    {
        syslog(LOG_ERR,qPrintable(QString("Audit log file: %1 does not exist").arg(AUDIT_LOG_PATH)));
        return;
    }

    if (file.open(QIODevice::ReadOnly))
    {
        QTextStream in(&file);

        QString line;
        QJsonObject logEntry;
        while(!in.atEnd()) {

            line = in.readLine();
            logEntry = (QJsonDocument::fromJson(line.toStdString().c_str())).object();

            row.append(new QStandardItem(logEntry["Date-time"].toString()));
            row.append(new QStandardItem(logEntry["username"].toString()));
            row.append(new QStandardItem(logEntry["App_name"].toString()));
            row.append(new QStandardItem(logEntry["event_category"].toString()));
            row.append(new QStandardItem(logEntry["event_desc"].toString()));

            appendRow(row);
            row.clear();
        }
        file.close();
    }
}

QML代码

 TableView {
        id: auditLogTable
        [geometry]   
        model: auditLogModelObj

        TableViewColumn {
            role: "DateTime"
            title: qsTr("Local Time")
            width: auditLogTable.width * 0.15
        }

        TableViewColumn {
            role: "Name"
            title: qsTr("Created By")
            width: auditLogTable.width * 0.1
        }

        TableViewColumn {
            role: "Application"
            title: qsTr("app name")
            width: auditLogTable.width * 0.40
        }

        TableViewColumn {
            role: "Category"
            title: qsTr("Category")
            width: auditLogTable.width * 0.2
        }

        TableViewColumn {
            role: "Description"
            title: qsTr("Detail")
            width: auditLogTable.width * 0.40
        }
    }

Answer 1

我不明白你在 setColumnMapping() 中试图做什么，你也不需要使用 roleNames()。此外，您使用的 TableView 只接受列表类型的模型，在这种情况下角色将是列，考虑到解决方案是:

*.h

class AuditLogsModel : public QStandardItemModel
{
public:
    enum AuditRoles{
        DateTimeRole = Qt::UserRole + 1,
        UsernameRole,
        ApplicationRole,
        CategoryRole,
        DescriptionRole
    };
    AuditLogsModel(QObject *parent=nullptr);
    void loadData();
};

*.cpp

AuditLogsModel::AuditLogsModel(QObject *parent):
    QStandardItemModel(parent)
{
    QHash<int, QByteArray> roles;
    roles[DateTimeRole] = "DateTime";
    roles[UsernameRole] = "Name";
    roles[ApplicationRole] = "Application";
    roles[CategoryRole] = "Category";
    roles[DescriptionRole] = "Description";
    setItemRoleNames(roles);
}

void AuditLogsModel::loadData()
{
    QFile file(AUDIT_LOG_PATH);
    if(!file.exists() )
    {
        syslog(LOG_ERR,qPrintable(QString("Audit log file: %1 does not exist").arg(AUDIT_LOG_PATH)));
        return;
    }

    if (file.open(QIODevice::ReadOnly))
    {
        QTextStream in(&file);
        QString line;
        QJsonObject logEntry;
        while(!in.atEnd()) {
            QStandardItem *row = new QStandardItem;
            line = in.readLine();
            logEntry = (QJsonDocument::fromJson (line.toStdString().c_str())).object();
            row->setData(logEntry["Date-time"].toString(), DateTimeRole);
            row->setData(logEntry["username"].toString(), UsernameRole);
            row->setData(logEntry["App_name"].toString(), ApplicationRole);
            row->setData(logEntry["event_category"].toString(), CategoryRole);
            row->setData(logEntry["event_desc"].toString(), DescriptionRole);
            appendRow(row);
        }
        file.close();
    }
}