在QML中使用QtWidgets的QFileDialog_qml qfiledialog

QML 中虽然也提供了 FileDialog 组件，但是使用体验远不如 QtWidgets 中的 QFileDialog，故做了简单的封装，使得可以在 QML 中使用 QFileDialog 来选择文件或者文件夹。

因为[Qt文档]提示不应直接在 QML 逻辑中启用自己的事件循环，所以我是通过信号槽来弹出和传递返回结果，操作流程和 QML 的 FileDialog 类似。

Demo 链接：

https://github.com/gongjianbo/MyTestCode/tree/master/Qml/FileDialogWrap

主要代码：

#pragma once
#include <QObject>
#include <QUrl>
#include <QSettings>
#include <QFileDialog>
 
/**
 * @brief 包装QFileDialog在QML中使用
 * @author 龚建波
 * @date 2022-12-31
 * @details
 * 参考：https://doc.qt.io/qt-5/qtquick-performance.html
 * 文档指出我们不应该在qml逻辑中执行自己的事件循环，所以通过信号槽异步调用对话框exec
 * 而操作结果也只能通过信号传递，不能像cpp代码那样exec后面直接获取结果
 */
class FileDialogWrap : public QObject
{
    Q_OBJECT
    Q_PROPERTY(int mode READ getMode WRITE setMode NOTIFY modeChanged)
    Q_PROPERTY(QString title READ getTitle WRITE setTitle NOTIFY titleChanged)
    Q_PROPERTY(QStringList nameFilters READ getNameFilters WRITE setNameFilters NOTIFY nameFiltersChanged)
    Q_PROPERTY(QUrl currentUrl READ getCurrentUrl NOTIFY currentUrlChanged)
    Q_PROPERTY(QList<QUrl> currentUrls READ getCurrentUrls NOTIFY currentUrlsChanged)
public:
    enum WorkMode {
        SelectFile, //单选文件
        SelectFiles, //多选文件
        SelectDir, //选择目录
        SaveFile //保存文件
    };
    Q_ENUM(WorkMode)
public:
    explicit FileDialogWrap(QObject *parent = nullptr);
    ~FileDialogWrap();
 
    //工作模式，枚举WorkMode
    int getMode() const;
    void setMode(int mode);
 
    //标题设置
    QString getTitle() const;
    void setTitle(const QString &title);
 
    //后缀过滤
    QStringList getNameFilters() const;
    void setNameFilters(const QStringList &filters);
 
    //单选结果
    QUrl getCurrentUrl() const;
    void setCurrentUrl(const QUrl &url);
 
    //多选结果
    QList<QUrl> getCurrentUrls() const;
    void setCurrentUrls(const QList<QUrl> &urls);
 
    Q_INVOKABLE void open();
    Q_INVOKABLE void close();
    //打开前选中某个路径，带文件名则作为选中的文件名
    Q_INVOKABLE void selectUrl(const QUrl &url);
 
    //桌面路径
    Q_INVOKABLE static QString desktopPath();
    Q_INVOKABLE static QUrl desktopUrl();
    //设置ini配置路径，qml初始化之前cpp中设置
    static void initSetting(const QString &filepath, const QSettings::Format &format = QSettings::IniFormat);
 
private:
    QString getDefaultPath();
    void setDefaultPath(const QString &dirpath);
 
private slots:
    void openDialog();
 
signals:
    void __openRequest();
    void __closeRequest();
    void accepted();
    void rejected();
 
    void modeChanged();
    void titleChanged();
    void nameFiltersChanged();
    void currentUrlChanged();
    void currentUrlsChanged();
 
private:
    //ini配置文件路径
    inline static QString iniPath;
    inline static QSettings::Format iniFormat{QSettings::IniFormat};
    //对话框
    QFileDialog *dialog;
    //模式，选择文件还是目录等
    int workMode{FileDialogWrap::SelectFile};
    //文件名过滤
    QStringList nameFilters{"All (*.*)"};
    //单选结果，当前选中路径
    QUrl currentUrl;
    //多选结果
    QList<QUrl> currentUrls;
    //selectUrl可设置，下次弹出时生效
    QUrl nextUrl;
};

#include "FileDialogWrap.h"
#include <QCoreApplication>
#include <QStandardPaths>
#include <QFileInfo>
#include <QDebug>
 
FileDialogWrap::FileDialogWrap(QObject *parent)
    : QObject{parent}
    , dialog{new QFileDialog}
{
    setTitle(QCoreApplication::applicationName());
    connect(this, &FileDialogWrap::__openRequest, this, &FileDialogWrap::openDialog, Qt::QueuedConnection);
    connect(this, &FileDialogWrap::__closeRequest, this, [=](){
        dialog->reject();
    }, Qt::QueuedConnection);
}
 
FileDialogWrap::~FileDialogWrap()
{
    dialog->deleteLater();
}
 
int FileDialogWrap::getMode() const
{
    return workMode;
}
 
void FileDialogWrap::setMode(int mode)
{
    if (mode != workMode) {
        workMode = mode;
        emit modeChanged();
    }
}
 
QString FileDialogWrap::getTitle() const
{
    return dialog->windowTitle();
}
 
void FileDialogWrap::setTitle(const QString &title)
{
    if (title != getTitle()) {
        dialog->setWindowTitle(title);
        emit titleChanged();
    }
}
 
QStringList FileDialogWrap::getNameFilters() const
{
    return nameFilters;
}
 
void FileDialogWrap::setNameFilters(const QStringList &filters)
{
    if (filters != nameFilters) {
        nameFilters = filters;
        emit nameFiltersChanged();
    }
}
 
QUrl FileDialogWrap::getCurrentUrl() const
{
    return currentUrl;
}
 
void FileDialogWrap::setCurrentUrl(const QUrl &url)
{
    if (url != currentUrl) {
        currentUrl = url;
        emit currentUrlChanged();
    }
}
 
QList<QUrl> FileDialogWrap::getCurrentUrls() const
{
    return currentUrls;
}
 
void FileDialogWrap::setCurrentUrls(const QList<QUrl> &urls)
{
    if (urls != currentUrls) {
        currentUrls = urls;
        emit currentUrlsChanged();
    }
}
 
void FileDialogWrap::open()
{
    if (dialog->isVisible())
        return;
    emit __openRequest();
}
 
void FileDialogWrap::close()
{
    if (!dialog->isVisible())
        return;
    emit __closeRequest();
}
 
void FileDialogWrap::selectUrl(const QUrl &url)
{
    nextUrl = url;
}
 
QString FileDialogWrap::desktopPath()
{
    return QStandardPaths::writableLocation(QStandardPaths::DesktopLocation);
}
 
QUrl FileDialogWrap::desktopUrl()
{
    return QUrl::fromLocalFile(desktopPath());
}
 
void FileDialogWrap::initSetting(const QString &filepath, const QSettings::Format &format)
{
    iniPath = filepath;
    iniFormat = format;
}
 
QString FileDialogWrap::getDefaultPath()
{
    //QFileDialog默认实现在构造时恢复，析构时保存
    //QSettings settings(QSettings::UserScope, QLatin1String("QtProject"));
    //settings.beginGroup(QLatin1String("FileDialog"));
    //记录上一次选择的路径
    QSettings setting(iniPath, QSettings::IniFormat);
    QString dirpath = setting.value("LastPath").toString();
    if (dirpath.isEmpty()) {
        //默认桌面路径
        dirpath = QStandardPaths::writableLocation(QStandardPaths::DesktopLocation);
    }
    qDebug()<<"get default"<<dirpath;
    return dirpath;
}
 
void FileDialogWrap::setDefaultPath(const QString &dirpath)
{
    QSettings setting(iniPath, QSettings::IniFormat);
    setting.setValue("LastPath", dirpath);
    qDebug()<<"set default"<<dirpath;
}
 
void FileDialogWrap::openDialog()
{
    switch (workMode) {
    case SelectFile:
    {
        dialog->setFileMode(QFileDialog::ExistingFile);
    }
        break;
    case SelectFiles:
    {
        dialog->setFileMode(QFileDialog::ExistingFiles);
    }
        break;
    case SelectDir:
    {
        dialog->setOption(QFileDialog::ShowDirsOnly);
        //参考源码中的写法
        QT_WARNING_PUSH
        QT_WARNING_DISABLE_DEPRECATED
        dialog->setFileMode(QFileDialog::DirectoryOnly);
        QT_WARNING_POP
 
    }
        break;
    case SaveFile:
    {
        dialog->setFileMode(QFileDialog::AnyFile);
        dialog->setAcceptMode(QFileDialog::AcceptSave);
    }
        break;
    default: break;
    }
 
    dialog->setNameFilters(nameFilters);
    //设置了url就用设置的，否则用上次保存的目录
    //selectUrl设置nextUrl
    if (nextUrl.isValid()) {
        QFileInfo info(nextUrl.toLocalFile());
        if (info.isDir()) {
            dialog->setDirectory(info.absoluteFilePath());
        } else {
            dialog->setDirectory(info.absolutePath());
            dialog->selectFile(info.fileName());
        }
        nextUrl.clear();
    } else {
        dialog->setDirectory(getDefaultPath());
    }
 
    const int ret = dialog->exec();
    if (ret == QDialog::Rejected) {
        emit rejected();
        return;
    }
    auto &&urls = dialog->selectedUrls();
    if (urls.isEmpty()) {
        setCurrentUrl(QUrl());
        setDefaultPath(desktopPath());
    } else {
        QUrl first_url = urls.first();
        setCurrentUrl(first_url);
        //保存目录到配置文件
        QFileInfo info(first_url.toLocalFile());
        if (info.isDir()) {
            setDefaultPath(info.absoluteFilePath());
        } else {
            setDefaultPath(info.absolutePath());
        }
    }
    setCurrentUrls(urls);
    emit accepted();
}