Re: [PyGObject] Drag & Drop in a TreeView

[Reuben Rissler <silrep emypeople net>]

On 07/22/2018 04:26 PM, c.buhtz--- via gtk-app-devel-list wrote:
> I am totally confused about this topic. I think I miss some fundamental
> understanding on how PyGObject works here.
>
> I want to drag & drop items of one TreeView inside itself. Not other
> widgets or applications. I just want to drag item 2 and drop it between
> item 4 and 5.
<snip>

This is how I have done it in the past. Note, I do not proclaim 
spectacular or Pythonic code, and would humbly accept any corrections 
and/or better ways to accomplish this. It seems to me there should be a 
way to let the TreeView do this work itself, but alas, I have not found 
it yet.



#!/usr/bin/env python3

import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk
from gi.repository import Gdk


class MainWindow(Gtk.Window):

    def __init__(self):
        Gtk.Window.__init__(self, title="TreeView Drag and Drop")
        self.connect("delete-event", Gtk.main_quit)
        self.set_default_size(400, 300)

        # "model" with dummy data
        self.store = Gtk.TreeStore(str, str)
        for i in range(5):
            self.store.append(None, ['Item {}'.format(i), 
'{}'.format(i*100)]) # treeview
        self.view = Gtk.TreeView(model=self.store)
        self.add(self.view)

        # build columsn
        colA = Gtk.TreeViewColumn('Col A', Gtk.CellRendererText(), text=0)
        self.view.append_column(colA)
        colB = Gtk.TreeViewColumn('Col B', Gtk.CellRendererText(), text=1)
        self.view.append_column(colB)

        # DnD events
        self.view.connect("drag-data-received", self.drag_data_received)
        self.view.connect("drag-data-get", self.drag_data_get)

        target_entry = Gtk.TargetEntry.new('text/plain', 2, 0)
self.view.enable_model_drag_source(Gdk.ModifierType.BUTTON1_MASK,[target_entry], 
Gdk.DragAction.DEFAULT|Gdk.DragAction.MOVE)
self.view.enable_model_drag_dest([target_entry],Gdk.DragAction.DEFAULT|Gdk.DragAction.MOVE)

    def drag_data_get (self, treeview, drag_context, data, info, time):
        model, path = treeview.get_selection().get_selected_rows()
        data.set_text(str(path[0]), -1)

    def drag_data_received (self, treeview, drag_context, x,y, 
data,info, time):
        store = treeview.get_model()
        source_path = data.get_text()
        source_iter = store.get_iter(source_path)
        dest_path = self.view.get_dest_row_at_pos(x, y)
        if dest_path != None:
            dest_iter = store.get_iter(dest_path[0])
            if dest_path[1] == Gtk.TreeViewDropPosition.BEFORE:
                store.move_before(source_iter, dest_iter)
            else:
                store.move_after(source_iter, dest_iter)
        treeview.emit_stop_by_name("drag-data-received")

win = MainWindow()
win.show_all()
Gtk.main()