code_app/app/scanner/custom_file_dialog.h

#ifndef CUSTOM_FILE_DIALOG_H
#define CUSTOM_FILE_DIALOG_H

#include <QFileDialog>
#include <QLineEdit>
#include <QPushButton>
#include <QListWidget>
#include <QLayout>
#include <QButtonGroup>
#include <string>

#define USE_FILE_DLG_WITHOUT_PROMPT

template<class T>
class custom_file_dlg
{
    QLineEdit*  edit_;
    QLineEdit*  new_;
    QPushButton *save_;
    QFileDialog *fdlg_;
    QListView *list_;

    enum find_cls
    {
        FIND_BUTTON = 1,
        FIND_LINE_EDIT,
        FIND_LIST,
    };
    typedef struct _find_ctrl
    {
        int         cls;
        std::string title;
        QObject     *found;
    }FINDCTRL, *LPFINDCTRL;

    static bool find_ctrls(QObject* obj, LPFINDCTRL ret)
    {
        if(ret->cls == FIND_BUTTON)
        {
            QPushButton* btn = dynamic_cast<QPushButton*>(obj);
            if(btn)
            {
                std::string t(btn->text().toStdString());
                if(ret->title.empty() || t == ret->title)   // "\344\277\235\345\255\230(&S)")
                {
                    ret->found = obj;
                    return true;
                }
            }

            QButtonGroup* grp = dynamic_cast<QButtonGroup*>(obj);
            if(grp)
            {
                printf("Found button-group with %d buttons\n", grp->buttons().size());
                QList<QAbstractButton*> btns = grp->buttons();
                for(auto& b : btns)
                {
                    btn = dynamic_cast<QPushButton*>(b);
                    if(btn)
                    {
                        std::string t(btn->text().toStdString());
                        if(ret->title.empty() || t == ret->title)   // "\344\277\235\345\255\230(&S)")
                        {
                            ret->found = obj;
                            return true;
                        }
                    }
                }
            }
        }
        else if(ret->cls == FIND_LINE_EDIT)
        {
            QLineEdit* edit = dynamic_cast<QLineEdit*>(obj);
            if(edit)
            {
                std::string t(edit->text().toStdString());
                if(ret->title.empty() || t == ret->title)   // "\344\277\235\345\255\230(&S)")
                {
                    ret->found = obj;
                    return true;
                }
            }
        }
        else if(ret->cls == FIND_LIST)
        {
            QListView *v = dynamic_cast<QListView*>(obj);
            if(v)
            {
                std::string t(v->objectName().toStdString());
                if(ret->title.empty() && ret->title.empty())    // || t == ret->title)
                {
                    ret->found = obj;
                    return true;
                }
            }
        }


        QListWidget *l = dynamic_cast<QListWidget*>(obj);
        if(l)
        {
            printf("Found list widget\n");
        }
        else {
            QListView *v = dynamic_cast<QListView*>(obj);
            if(v)
                printf("Found list view: %s\n", v->objectName().toStdString().c_str());
        }
        QObjectList objs(obj->children());
        for(auto& o : objs)
        {
            if(find_ctrls(o, ret))
                return true;
        }

        return false;
    }
    QPushButton* save_button(void){return save_;}
    QLineEdit* input_edit(bool org){return org ? edit_ : new_;}
    QListView* file_list(void){return list_;}
    void replace_input(QLineEdit* from, QLineEdit* tobe)
    {
        fdlg_->layout()->replaceWidget(from, tobe);
        from->hide();
        tobe->show();
    }

protected slots:
    virtual void on_file_dialog_textChanged(const QString &path) = 0;
    virtual void on_file_dialog_returnPressed() = 0;

protected:
    custom_file_dlg() : edit_(nullptr), new_(nullptr), save_(nullptr), fdlg_(nullptr), list_(nullptr)
    {
    }
    ~custom_file_dlg()
    {
    }

public:
    static QLineEdit* find_input_box(QFileDialog* host)
    {
        FINDCTRL    fc;
        QObjectList objs(host->children());

        fc.cls = FIND_LINE_EDIT;
        fc.found = nullptr;
        for(auto& o : objs)
        {
            QString objName = o->objectName();
            if(custom_file_dlg::find_ctrls(o, &fc))
                break;
        }

        return dynamic_cast<QLineEdit*>(fc.found);
    }
    static QPushButton* find_button(QFileDialog* host, const char* title)
    {
        FINDCTRL    fc;
        QObjectList objs(host->children());

        fc.cls = FIND_BUTTON;
        fc.title = (title && *title) ? title : "";
        fc.found = nullptr;
        for(auto& o : objs)
        {
            QString objName = o->objectName();
            if(custom_file_dlg::find_ctrls(o, &fc))
                break;
        }

        return dynamic_cast<QPushButton*>(fc.found);
    }
    static QListView* find_list(QFileDialog* host, const char* title)
    {
        FINDCTRL    fc;
        QObjectList objs(host->children());

        fc.cls = FIND_LIST;
        fc.title = (title && *title) ? title : "";
        fc.found = nullptr;
        for(auto& o : objs)
        {
            if(custom_file_dlg::find_ctrls(o, &fc))
                break;
        }

        return dynamic_cast<QListView*>(fc.found);
    }


protected:
    bool init_custom_file_dlg(QFileDialog* fdlg)
    {
        new_ = new QLineEdit(((T*)this));
        fdlg_ = fdlg;
        edit_ = custom_file_dlg::find_input_box(fdlg);
        save_ = custom_file_dlg::find_button(fdlg, QObject::tr("&Save").toStdString().c_str());
        list_ = custom_file_dlg::find_list(fdlg, "");
        if(edit_ && save_ && list_)
        {
            enable_prompt(false);
            ((T*)this)->connect(new_, SIGNAL(textChanged(const QString&)), (T*)this, SLOT(on_file_dialog_textChanged(const QString)));
            ((T*)this)->connect(new_, SIGNAL(returnPressed()), (T*)this, SLOT(on_file_dialog_returnPressed()));
            ((T*)this)->connect(fdlg, SIGNAL(currentChanged(const QString&)), (T*)this, SLOT(on_file_dialog_textChanged(const QString)));
            fdlg->setFocus();
            new_->setFocus();
        }
        return edit_ && save_;
    }
    void enable_prompt(bool enable)
    {
        if(edit_)
        {
            if(enable)
                replace_input(new_, edit_);
            else
                replace_input(edit_, new_);
        }
    }
    void on_file_name_changed(const QLineEdit* ctrl, const QString& text)
    {
        if(ctrl == nullptr) // send by QFileDialog
        {
            std::string name(text.toStdString());
            size_t      pos = name.rfind('/');
            if(pos++ != std::string::npos)
                name.erase(0, pos);
            new_->setText(QString::fromStdString(name));
        }
        else if(ctrl == edit_ && new_)
            new_->setText(text);
        else if(edit_)
        {
            QString ext(text), sel_ext(((T*)this)->getSaveExt());
            int     pos = ext.lastIndexOf('.');

            list_->clearSelection();
            if(pos == -1)
                edit_->setText(text + sel_ext);
            else {
                ext = ext.right(ext.length() - pos);
                if(ext.compare(sel_ext, Qt::CaseInsensitive) == 0)
                    edit_->setText(text);
                else
                    edit_->setText(text + sel_ext);
            }
        }

        if(save_)
            save_->setEnabled(!text.isEmpty());
    }
    void on_file_name_press_return(void)
    {
        emit save_->clicked();
    }
};


#endif // CUSTOM_FILE_DIALOG_H