QML学习——Qt Quick Controls 1 Examples Calendar/FileSystemBrowser（九）

Taiga_2024-07-26 9:40
02 File System Browser

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Notes:

  • 使用了自定义的继承自QFileSystemModel的类，在原有的基础上新加了角色(role)，并且重写了QFileSystemModel中的data函数、及角色和字符串描述对应的哈希表；

  • 使用系统的文件资源管理器打开该文件的链接：Qt.openUrlExternally(url)

  • 关于QML的几种注册及属性：

    • qmlRegisterType方式注册：

      • 优点：

        1. QML 文件中可以直接使用注册的类型，创建其实例，并与其进行交互。
        2. 支持类型安全，QML 编辑器（如 Qt Creator）可以提供自动补全和类型检查。
        3. 适用于需要多个实例的情况，因为 QML 可以直接创建和管理这些实例。

      • 缺点：

        1. 需要 C++ 类与 QML 之间进行明确的类型匹配。
        2. 如果类具有复杂的构造函数或需要特定的初始化逻辑，可能需要额外的设置。

    • qmlRegisterUncreatableType注册一个C++类型：

      • 该类型不可实例化，但应可识别为QML类型系统的类型。
      • 如果类型的枚举或附加属性应该可以从QML访问，但是类型本身不应该是可实例化的，那么这很有用。

    • setContextProperty()：将 C++ 对象或值设置为 QML 上下文的属性，这样 QML 文件中就可以通过属性名直接访问它。

      • 优点：
        1. 简单直接，适用于将单例或全局对象暴露给 QML。
        2. 不需要复杂的类型匹配或注册。
        3. 适用于需要多个实例的情况，因为 QML 可以直接创建和管理这些实例。
      • 缺点：
        1. 不支持类型安全，QML 编辑器可能无法提供自动补全或类型检查。
        2. 只能在 QML 文件中访问一个特定的实例（通常是单例）。

  • 关于Q_ENUM：

    • This function is obsolete. It is provided to keep old source code working. We strongly advise against using it in new code.
    • In new code, you should prefer the use of the Q_ENUM() macro, which makes the type available also to the meta type system.

  • If the model is a string list or object list, the delegate is also exposed to a read-only modelData property that holds the string or object data.

  • Note: model, index, and modelData roles are not accessible if the delegate contains required properties, unless it has also required properties with matching names.

SourceCode:

  • TestCustomFileSystemBrowser.qml

js 复制代码 
import QtQuick 2.15
import QtQuick.Controls 1.5
import QtQml.Models 2.15

import TestClasses.QC1.OfficialExample.CustomFileSystemModel 1.0

Item {
    width: 640
    height: 480

    MenuBar {
        Menu {
            title: qsTr("File")
            MenuItem {
                text: qsTr("Exit")
                onTriggered: Qt.quit();
            }
        }
    }

    Row {
        id: row_ID
        anchors.top: parent.top
        anchors.topMargin: 12
        anchors.horizontalCenter: parent.horizontalCenter

        ExclusiveGroup {
            id: eg
        }

        Repeater {
            model: [ "None", "Single", "Extended", "Multi", "Contig."]
            Button {
                //If the model is a string list or object list, the delegate is also exposed to a read-only modelData property that holds the string or object data.
                text: modelData
                exclusiveGroup: eg
                checkable: true
                checked: index === 1
                onClicked: view.selectionMode = index
            }
        }
    }

    ItemSelectionModel {
        id: sel
        model: customFSysModel
    }

    TreeView {
        id: view
        anchors.fill: parent
        anchors.margins: 2 * 12 + row_ID.height
        model: customFSysModel
        rootIndex: rootPathIndex
        selection: sel

        TableViewColumn {
            title: "Name"
            role: "fileName"
            resizable: true
        }

        TableViewColumn {
            title: "Size"
            role: "byteSize"
            resizable: true
            horizontalAlignment : Text.AlignRight
            width: 70
        }

        TableViewColumn {
            title: "Permissions"
            role: "customFilePermissions"
            resizable: true
            width: 100
        }

        TableViewColumn {
            title: "Date Modified"
            role: "lastModified"
            resizable: true
        }

        onActivated : {
            var url = customFSysModel.data(index, CustomFSysModel.UrlStringRole)
            //使用系统的文件资源管理器打开该文件的链接
            Qt.openUrlExternally(url)
        }
    }
}

  • customFileSystemModel.h

c++ 复制代码 
#ifndef CUSTOMFILESYSTEMMODEL_H
#define CUSTOMFILESYSTEMMODEL_H

#include <QFileSystemModel>
#include <QObject>

class CustomFileSystemModel : public QFileSystemModel
{
    Q_OBJECT
public:
    explicit CustomFileSystemModel(QObject *parent = nullptr);

    //自定义角色
    enum Roles  {
        SizeRole = ((Qt::UserRole + 3 == QFileSystemModel::FilePermissions) ? (Qt::UserRole + 4) : (QFileSystemModel::FilePathRole + 1)), //0x0104
        CustomFilePermissionsRole,
        LastModifiedRole,
        UrlStringRole
    };
    //This function is obsolete. It is provided to keep old source code working. We strongly advise against using it in new code.
    //In new code, you should prefer the use of the Q_ENUM() macro, which makes the type available also to the meta type system.
    Q_ENUM(Roles)

    // QAbstractItemModel interface
public:
    //重写QFileSystemModel中的data函数
    QVariant data(const QModelIndex &index, int role) const override;
    //重写QAbstractItemModel中的roleNames函数
    QHash<int, QByteArray> roleNames() const override;
};

//file permissions:

static inline QString permissionString(const QFileInfo &fi)
{
    const QFile::Permissions permissions = fi.permissions();
    QString result = QLatin1String("----------");
    if (fi.isSymLink()) {
        result[0] = QLatin1Char('l');
    } else if (fi.isDir()) {
        result[0] = QLatin1Char('d');
    } else {
        result[0] = QLatin1Char('-');
    }

    if (permissions & QFileDevice::ReadUser)
        result[1] = QLatin1Char('r');
    if (permissions & QFileDevice::WriteUser)
        result[2] = QLatin1Char('w');
    if (permissions & QFileDevice::ExeUser)
        result[3] = QLatin1Char('x');
    if (permissions & QFileDevice::ReadGroup)
        result[4] = QLatin1Char('r');
    if (permissions & QFileDevice::WriteGroup)
        result[5] = QLatin1Char('w');
    if (permissions & QFileDevice::ExeGroup)
        result[6] = QLatin1Char('x');
    if (permissions & QFileDevice::ReadOther)
        result[7] = QLatin1Char('r');
    if (permissions & QFileDevice::WriteOther)
        result[8] = QLatin1Char('w');
    if (permissions & QFileDevice::ExeOther)
        result[9] = QLatin1Char('x');
    return result;
}

//human readable file size:
static inline QString sizeString(const QFileInfo &fi)
{
    if (!fi.isFile())
        return QString();
    const qint64 size = fi.size();
    if (size > static_cast<qint64>(1024) * 1024 * 1024 * 10)
        return QString::number(size / (1024 * 1024 * 1024)) + QLatin1Char('G');
    if (size > 1024 * 1024 * 10)
        return QString::number(size / (1024 * 1024)) + QLatin1Char('M');
    if (size > 1024 * 10)
        return QString::number(size / 1024) + QLatin1Char('K');
    return QString::number(size) + QLatin1Char('B');
}

#endif // CUSTOMFILESYSTEMMODEL_H

  • customFileSystemModel.cpp

c++ 复制代码 
#include "customFileSystemModel.h"

#include <QLocale>
#include <QUrl>
#include <QDateTime>

CustomFileSystemModel::CustomFileSystemModel(QObject *parent) : QFileSystemModel(parent)
{

}

//重写QFileSystemModel中的data函数
QVariant CustomFileSystemModel::data(const QModelIndex &index, int role) const
{
    //自定义数据
    if (index.isValid() && role >= SizeRole) {
        switch (role) {
        case SizeRole:
            return QVariant(sizeString(fileInfo(index)));
        case CustomFilePermissionsRole:
            return QVariant(permissionString(fileInfo(index)));
        case LastModifiedRole:
            return QVariant(QLocale::system().toString(fileInfo(index).lastModified(), QLocale::ShortFormat)); //根据本地系统时间的短格式来设定最后修改时间样式
        case UrlStringRole:
            return QVariant(QUrl::fromLocalFile(filePath(index)).toString());
        default:
            break;
        }
    }
    //原始数据
    return QFileSystemModel::data(index, role);
}

//Returns the model's names. //QML Role Name
QHash<int, QByteArray> CustomFileSystemModel::roleNames() const
{
    //原有的角色名字
    QHash<int, QByteArray> result = QFileSystemModel::roleNames();
    result.insert(SizeRole, QByteArrayLiteral("byteSize"));
    result.insert(CustomFilePermissionsRole, QByteArrayLiteral("customFilePermissions"));
    result.insert(LastModifiedRole, QByteArrayLiteral("lastModified"));
    return result;
}
01 Calendar

  • 本地数据库存储数据

  • SQL语句

  • event.h

c++ 复制代码 
#ifndef EVENT_H
#define EVENT_H

#include <QDateTime>
#include <QObject>
#include <QString>

class Event : public QObject
{
    Q_OBJECT

    Q_PROPERTY(QString name READ name WRITE setName NOTIFY nameChanged)
    Q_PROPERTY(QDateTime startDate READ startDate WRITE setStartDate NOTIFY startDateChanged)
    Q_PROPERTY(QDateTime endDate READ endDate WRITE setEndDate NOTIFY endDateChanged)
public:
    explicit Event(QObject *parent = 0);

    QString name() const;
    void setName(const QString &name);

    QDateTime startDate() const;
    void setStartDate(const QDateTime &startDate);

    QDateTime endDate() const;
    void setEndDate(const QDateTime &endDate);
signals:
    void nameChanged(const QString &name);
    void startDateChanged(const QDateTime &startDate);
    void endDateChanged(const QDateTime &endDate);
private:
    QString mName;
    QDateTime mStartDate;
    QDateTime mEndDate;
};

#endif

  • event.cpp

c++ 复制代码 
#include "event.h"

Event::Event(QObject *parent) :
    QObject(parent)
{
}

QString Event::name() const
{
    return mName;
}

void Event::setName(const QString &name)
{
    if (name != mName) {
        mName = name;
        emit nameChanged(mName);
    }
}

QDateTime Event::startDate() const
{
    return mStartDate;
}

void Event::setStartDate(const QDateTime &startDate)
{
    if (startDate != mStartDate) {
        mStartDate = startDate;
        emit startDateChanged(mStartDate);
    }
}

QDateTime Event::endDate() const
{
    return mEndDate;
}

void Event::setEndDate(const QDateTime &endDate)
{
    if (endDate != mEndDate) {
        mEndDate = endDate;
        emit endDateChanged(mEndDate);
    }
}

  • sqleventmodel.h

c++ 复制代码 
#ifndef SQLEVENTMODEL_H
#define SQLEVENTMODEL_H

#include <QList>
#include <QObject>


class SqlEventModel : public QObject
{
    Q_OBJECT

public:
    SqlEventModel();

    Q_INVOKABLE QList<QObject*> eventsForDate(const QDate &date);

private:
    static void createConnection();
};

#endif

  • sqleventmodel.cpp

c++ 复制代码 
#include "sqleventmodel.h"
#include "event.h"

#include <QDebug>
#include <QFileInfo>
#include <QSqlError>
#include <QSqlQuery>

SqlEventModel::SqlEventModel()
{
    createConnection();
}

QList<QObject*> SqlEventModel::eventsForDate(const QDate &date)
{
    const QString queryStr = QString::fromLatin1("SELECT * FROM Event WHERE '%1' >= startDate AND '%1' <= endDate").arg(date.toString("yyyy-MM-dd"));
    QSqlQuery query(queryStr);
    if (!query.exec())
        qFatal("Query failed");

    QList<QObject*> events;
    while (query.next()) {
        Event *event = new Event(this);
        event->setName(query.value("name").toString());

        QDateTime startDate;
        startDate.setDate(query.value("startDate").toDate());
        startDate.setTime(QTime(0, 0).addSecs(query.value("startTime").toInt()));
        event->setStartDate(startDate);

        QDateTime endDate;
        endDate.setDate(query.value("endDate").toDate());
        endDate.setTime(QTime(0, 0).addSecs(query.value("endTime").toInt()));
        event->setEndDate(endDate);

        events.append(event);
    }

    return events;
}

/*
    Defines a helper function to open a connection to an
    in-memory SQLITE database and to create a test table.
*/
void SqlEventModel::createConnection()
{
    //SQLite version 3 or above
    //defalut connectionName
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName(":memory:"); //based on memory
    if (!db.open()) {
        qFatal("Cannot open database");
        return;
    }

    QSqlQuery query;
    // We store the time as seconds because it's easier to query.
    query.exec("create table Event (name TEXT, startDate DATE, startTime INT, endDate DATE, endTime INT)");
    query.exec("insert into Event values('Grocery shopping', '2014-01-01', 36000, '2014-01-01', 39600)");
    query.exec("insert into Event values('Ice skating', '2014-01-01', 57600, '2014-01-01', 61200)");
    query.exec("insert into Event values('Doctor''s appointment', '2014-01-15', 57600, '2014-01-15', 63000)");
    query.exec("insert into Event values('Conference', '2014-01-24', 32400, '2014-01-28', 61200)");

    return;
}

  • TestQC1Calendar.qml

js 复制代码 
import QtQuick 2.15
import QtQuick.Controls 1.4
import QtQuick.Controls.Styles 1.4
import QtQuick.Controls.Private 1.0

import TestClasses.QC1.OfficialExampleCalendar 1.0

Rectangle {
    width: 640
    height: 400
    color: "#f4f4f4"

    SystemPalette {
        id: systemPalette
    }

    SqlEventModel {
        id: eventModel
    }

    Flow {
        id: row
        anchors.fill: parent
        anchors.margins: 20
        spacing: 10
        layoutDirection: Qt.RightToLeft

        Calendar {
            id: calendar
            width: (parent.width > parent.height ? parent.width * 0.6 - parent.spacing : parent.width)
            height: (parent.height > parent.width ? parent.height * 0.6 - parent.spacing : parent.height)
            frameVisible: true
            weekNumbersVisible: true
            selectedDate: new Date(2014, 0, 1)
            focus: true

            style: CalendarStyle {
                dayDelegate: Item {
                    readonly property color sameMonthDateTextColor: "#444"
                    readonly property color selectedDateColor: Qt.platform.os === "osx" ? "#3778d0" : systemPalette.highlight
                    readonly property color selectedDateTextColor: "white"
                    readonly property color differentMonthDateTextColor: "#bbb"
                    readonly property color invalidDatecolor: "#dddddd"

                    Rectangle {
                        anchors.fill: parent
                        border.color: "transparent"
                        color: styleData.date !== undefined && styleData.selected ? selectedDateColor : "transparent"
                        anchors.margins: styleData.selected ? -1 : 0
                    }

                    Image {
                        visible: eventModel.eventsForDate(styleData.date).length > 0
                        anchors.top: parent.top
                        anchors.left: parent.left
                        anchors.margins: -1
                        width: 12
                        height: width
                        source: "qrc:/Icons/Used_Images/Icons/10_12used_QC1Calendar_Pinned.png"
                    }

                    Label {
                        id: dayDelegateText
                        text: styleData.date.getDate()
                        anchors.centerIn: parent
                        color: {
                            var color = invalidDatecolor;
                            if (styleData.valid) {
                                // Date is within the valid range.
                                color = styleData.visibleMonth ? sameMonthDateTextColor : differentMonthDateTextColor;
                                if (styleData.selected) {
                                    color = selectedDateTextColor;
                                }
                            }
                            color;
                        }
                    }
                }
            }
        }

        Component {
            id: eventListHeader

            Row {
                id: eventDateRow
                width: parent.width
                height: eventDayLabel.height
                spacing: 10

                Label {
                    id: eventDayLabel
                    text: calendar.selectedDate.getDate()
                    font.pointSize: 35
                }

                Column {
                    height: eventDayLabel.height

                    Label {
                        readonly property var options: { weekday: "long" }
                        text: Qt.locale().standaloneDayName(calendar.selectedDate.getDay(), Locale.LongFormat)
                        font.pointSize: 18
                    }
                    Label {
                        text: Qt.locale().standaloneMonthName(calendar.selectedDate.getMonth())
                              + calendar.selectedDate.toLocaleDateString(Qt.locale(), " yyyy")
                        font.pointSize: 12
                    }
                }
            }
        }

        Rectangle {
            width: (parent.width > parent.height ? parent.width * 0.4 - parent.spacing : parent.width)
            height: (parent.height > parent.width ? parent.height * 0.4 - parent.spacing : parent.height)
            border.color: Qt.darker(color, 1.2)

            ListView {
                id: eventsListView
                spacing: 4
                clip: true
                header: eventListHeader
                anchors.fill: parent
                anchors.margins: 10
                model: eventModel.eventsForDate(calendar.selectedDate)

                delegate: Rectangle {
                    width: eventsListView.width
                    height: eventItemColumn.height
                    anchors.horizontalCenter: parent.horizontalCenter

                    Image {
                        anchors.top: parent.top
                        anchors.topMargin: 4
                        width: 12
                        height: width
                        source: "qrc:/Icons/Used_Images/Icons/10_12used_QC1Calendar_Pinned.png"
                    }

                    Rectangle {
                        width: parent.width
                        height: 1
                        color: "#eee"
                    }

                    Column {
                        id: eventItemColumn
                        anchors.left: parent.left
                        anchors.leftMargin: 20
                        anchors.right: parent.right
                        height: timeLabel.height + nameLabel.height + 8

                        Label {
                            id: nameLabel
                            width: parent.width
                            wrapMode: Text.Wrap
                            text: modelData.name
                        }
                        Label {
                            id: timeLabel
                            width: parent.width
                            wrapMode: Text.Wrap
                            text: modelData.startDate.toLocaleTimeString(calendar.locale, Locale.ShortFormat)
                            color: "#aaa"
                        }
                    }
                }
            }
        }
    }
}
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