CODEWITHSUNDEEP
c++drag-and-dropgtk3gtkmm
Tyilo
Tyilo

Reputation: 30142

How to make a draggable GTK widget that will drop a file in other programs

I want to make a GTK widget, when dragged and dropped in another program, will act as if a file was dropped (behaving the same way as dragging a file from Nautilus).

I have tried 3 different ways of setting the drag data in the callback, but nothing seems to work:

#include <bits/stdc++.h>
#include <gtkmm.h>

#define FILENAME "/tmp/foo.txt"

int main(int argc, char *argv[]) {
    auto app = Gtk::Application::create(argc, argv, "com.tyilo.foo");

    Gtk::Window window;
    window.set_default_size(200, 200);
    window.set_keep_above();

    Gtk::Button button("Drag this");
    window.add(button);

    std::vector<Gtk::TargetEntry> listTargets;
    listTargets.push_back(Gtk::TargetEntry("text/uri-list"));
    //listTargets.push_back(Gtk::TargetEntry("text/plain"));
    //listTargets.push_back(Gtk::TargetEntry("text/plain;charset=utf-8"));
    //listTargets.push_back(Gtk::TargetEntry("UTF8_STRING"));
    //listTargets.push_back(Gtk::TargetEntry("COMPOUND_STRING"));
    //listTargets.push_back(Gtk::TargetEntry("TEXT"));
    //listTargets.push_back(Gtk::TargetEntry("STRING"));

    button.drag_source_set(listTargets, Gdk::ModifierType(GDK_BUTTON1_MASK | GDK_BUTTON3_MASK),
                           Gdk::DragAction(GDK_ACTION_COPY | GDK_ACTION_MOVE));
    button.drag_source_set_icon("document-save");

    button.signal_drag_data_get().connect([&](auto, auto selection_data, auto, auto) {
        std::cout << "Data get: " << selection_data.get_target() << std::endl;

        auto uri = Glib::filename_to_uri(FILENAME);
        std::cout << uri << std::endl;

        // All but one of (1), (2) and (3) should be commented out

        // (1)
        selection_data.set_uris({uri});

        // (2)
        //uri += "\r\n";
        //selection_data.set(selection_data.get_target(), 8, (const guchar*)uri.c_str(), uri.bytes());


        // (3)
        //selection_data.set("text/uri-list", "file:///tmp/foo.txt\r\n");
    });

    window.show_all();
    return app->run(window);
}

Do I need to specify more targets than just text/uri-list? Do I need to handle these differently?

Or am I doing something wrong with setting the selection data?

I'm using gtkmm3 version 3.24.1 and gtk3 version 3.24.8 and I'm compiling with:

g++ foo.cpp $(pkg-config gtkmm-3.0 --cflags --libs)

An easy way to test if it works, is try to drag the file to the following <input> tag in your browser:

<input type=file value="Drop here">

Upvotes: 5

Views: 846

Answers (1)

Marc
Marc

Reputation: 1

#include <gtkmm.h>
#include <glibmm.h>
#include <iostream>
#include <vector>

#define FILENAME "/tmp/foo.txt"

static void on_drag_data_get(  const Glib::RefPtr<Gdk::DragContext>& context,
                                    Gtk::SelectionData& selection_data, guint info, guint time){

    std::vector<Glib::ustring> vec_uris;
    vec_uris.push_back(Glib::filename_to_uri(FILENAME));
    std::cout << "File = " << vec_uris[0] << '\n';
    selection_data.set_uris(vec_uris);
}

int main(int argc, char *argv[])
{
    auto app = Gtk::Application::create(argc, argv, "com.tyilo.foo");

    Gtk::Window window;
    window.set_default_size(200, 200);
    window.set_keep_above();

    Gtk::Button button("Drag this");
    window.add(button);


    std::vector<Gtk::TargetEntry> listTargets;
    listTargets.push_back(Gtk::TargetEntry("text/uri-list"));
    button.drag_source_set(listTargets, Gdk::ModifierType::BUTTON1_MASK, Gdk::DragAction::ACTION_COPY);
    button.drag_source_add_uri_targets();
    button.drag_source_set_icon("document-save"); // x-office-spreadsheet, document


    button.signal_drag_data_get().connect(sigc::ptr_fun(&on_drag_data_get));


    window.show_all();
    return app->run(window);
}

Upvotes: 0

Related Questions