我正在移植 liblarch ，一个用于处理有向无环图的库，从 PyGTK (GTK2) 到 PyGObject introspection (GTK3)。我遇到了 GtkTreeView 的问题。

使用 liblarch 的应用程序需要按列对 GtkTreeView 进行排序，但同时，用户可以拖放行，将一行移动到另一行下。为此，我必须手动处理 dnd_data_get() 和 dnd_data_receive()，这完全没问题。

在 PyGTK 下工作的 GtkTreeView 有最小的设置。行已排序，用户可以移动行。

#!/usr/bin/python
# -*- coding: utf-8 -*-

import gtk

window = gtk.Window()
window.set_size_request(300, 200)
window.connect('delete_event', lambda w,e: gtk.main_quit())

# Define Liblarch Tree

store = gtk.TreeStore(str, str)
store.insert(None, -1, ["A", "Task A"])
store.insert(None, -1, ["B", "Task B"])
store.insert(None, -1, ["C", "Task C"])
d_parent = store.insert(None, -1, ["D", "Task D"])
store.insert(d_parent, -1, ["E", "Task E"])

# Define TreeView in similar way as it happens in GTG/Liblarch_gtk
tv = gtk.TreeView()

col = gtk.TreeViewColumn()
col.set_title("Title")
render_text = gtk.CellRendererText()
col.pack_start(render_text, expand=True)
col.add_attribute(render_text, 'markup', 1)
col.set_resizable(True)
col.set_expand(True)
col.set_sort_column_id(0)
tv.append_column(col)
tv.set_property("expander-column", col)

treemodel = store

def _sort_func(model, iter1, iter2):
    """ Sort two iterators by function which gets node objects.
    This is a simple wrapper which prepares node objects and then
    call comparing function. In other case return default value -1
    """
    node_a = model.get_value(iter1, 0)
    node_b = model.get_value(iter2, 0)
    if node_a and node_b:
        sort = cmp(node_a, node_b)
    else:
        sort = -1
    return sort

treemodel.set_sort_func(1, _sort_func)
tv.set_model(treemodel)

def on_child_toggled(treemodel2, path, iter, param=None):
    """ Expand row """
    if not tv.row_expanded(path):
        tv.expand_row(path, True)

treemodel.connect('row-has-child-toggled', on_child_toggled)

tv.set_search_column(1)
tv.set_property("enable-tree-lines", False)
tv.set_rules_hint(False)


#### Drag and drop stuff

dnd_internal_target = ''
dnd_external_targets = {}

def on_drag_fail(widget, dc, result):
    print "Failed dragging", widget, dc, result

def __init_dnd():
    """ Initialize Drag'n'Drop support

    Firstly build list of DND targets:
        * name
        * scope - just the same widget / same application
        * id

    Enable DND by calling enable_model_drag_dest(), 
    enable_model-drag_source()

    It didnt use support from gtk.Widget(drag_source_set(),
    drag_dest_set()). To know difference, look in PyGTK FAQ:
    http://faq.pygtk.org/index.py?file=faq13.033.htp&req=show
    """
    #defer_select = False

    if dnd_internal_target == '':
        error = 'Cannot initialize DND without a valid name\n'
        error += 'Use set_dnd_name() first'
        raise Exception(error)

    dnd_targets = [(dnd_internal_target, gtk.TARGET_SAME_WIDGET, 0)]
    for target in dnd_external_targets:
        name = dnd_external_targets[target][0]
        dnd_targets.append((name, gtk.TARGET_SAME_APP, target))

    tv.enable_model_drag_source( gtk.gdk.BUTTON1_MASK,
        dnd_targets, gtk.gdk.ACTION_DEFAULT | gtk.gdk.ACTION_MOVE)

    tv.enable_model_drag_dest(\
        dnd_targets, gtk.gdk.ACTION_DEFAULT | gtk.gdk.ACTION_MOVE)


def on_drag_data_get(treeview, context, selection, info, timestamp):
    """ Extract data from the source of the DnD operation.

    Serialize iterators of selected tasks in format 
    <iter>,<iter>,...,<iter> and set it as parameter of DND """
    print "on_drag_data_get(", treeview, context, selection, info, timestamp

    treeselection = treeview.get_selection()
    model, paths = treeselection.get_selected_rows()
    iters = [model.get_iter(path) for path in paths]
    iter_str = ','.join([model.get_string_from_iter(iter) for iter in iters])
    selection.set(dnd_internal_target, 0, iter_str)
    print "Sending", iter_str

def on_drag_data_received(treeview, context, x, y, selection, info,\
                          timestamp):
    """ Handle a drop situation.

    First of all, we need to get id of node which should accept
    all draged nodes as their new children. If there is no node,
    drop to root node.

    Deserialize iterators of dragged nodes (see self.on_drag_data_get())
    Info parameter determines which target was used:
        * info == 0 => internal DND within this TreeView
        * info > 0 => external DND

    In case of internal DND we just use Tree.move_node().
    In case of external DND we call function associated with that DND
    set by self.set_dnd_external()
    """
    print "on_drag_data_received", treeview, context, x, y, selection, info, timestamp

    model = treeview.get_model()
    destination_iter = None
    destination_tid = None
    drop_info = treeview.get_dest_row_at_pos(x, y)
    if drop_info:
        path, position = drop_info
        destination_iter = model.get_iter(path)
        if destination_iter:
            destination_tid = model.get_value(destination_iter, 0)

    # Get dragged iter as a TaskTreeModel iter
    # If there is no selected task (empty selection.data), 
    # explictly skip handling it (set to empty list)
    if selection.data == '':
        iters = []
    else:
        iters = selection.data.split(',')

    dragged_iters = []
    for iter in iters:
        print "Info", info
        if info == 0:
            try:
                dragged_iters.append(model.get_iter_from_string(iter))
            except ValueError:
                #I hate to silently fail but we have no choice.
                #It means that the iter is not good.
                #Thanks shitty gtk API for not allowing us to test the string
                print "Shitty iter", iter
                dragged_iter = None

        elif info in dnd_external_targets and destination_tid:
            f = dnd_external_targets[info][1]

            src_model = context.get_source_widget().get_model()
            dragged_iters.append(src_model.get_iter_from_string(iter))


    for dragged_iter in dragged_iters:
        if info == 0:
            if dragged_iter and model.iter_is_valid(dragged_iter):
                dragged_tid = model.get_value(dragged_iter, 0)
                try:
                    row = []
                    for i in range(model.get_n_columns()):
                        row.append(model.get_value(dragged_iter, i))
                    #tree.move_node(dragged_tid, new_parent_id=destination_tid)
                    print "move_after(%s, %s) ~ (%s, %s)" % (dragged_iter, destination_iter, dragged_tid, destination_tid)
                    #model.move_after(dragged_iter, destination_iter)
                    model.insert(destination_iter, -1, row)
                    model.remove(dragged_iter)
                except Exception, e:
                    print 'Problem with dragging: %s' % e
        elif info in dnd_external_targets and destination_tid:    
            source = src_model.get_value(dragged_iter,0)
            # Handle external Drag'n'Drop
            f(source, destination_tid)


dnd_internal_target = 'gtg/task-iter-str'
__init_dnd()
tv.connect('drag_data_get', on_drag_data_get)
tv.connect('drag_data_received', on_drag_data_received)
tv.connect('drag_failed', on_drag_fail)

window.add(tv)
window.show_all()

tv.expand_all()
gtk.main()

# vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4

我将此脚本移植到 PyGObject (GTK3) 中。我的代码:

#!/usr/bin/python
# -*- coding: utf-8 -*-

from gi.repository import Gtk, Gdk

window = Gtk.Window()
window.set_size_request(300, 200)
window.connect('delete_event', lambda w,e: Gtk.main_quit())

# Define Liblarch Tree

store = Gtk.TreeStore(str, str)
store.insert(None, -1, ["A", "Task A"])
store.insert(None, -1, ["B", "Task B"])
store.insert(None, -1, ["C", "Task C"])
d_parent = store.insert(None, -1, ["D", "Task D"])
store.insert(d_parent, -1, ["E", "Task E"])

# Define TreeView in similar way as it happens in GTG/Liblarch_gtk
tv = Gtk.TreeView()

col = Gtk.TreeViewColumn()
col.set_title("Title")
render_text = Gtk.CellRendererText()
col.pack_start(render_text, expand=True)
col.add_attribute(render_text, 'markup', 1)
col.set_resizable(True)
col.set_expand(True)
col.set_sort_column_id(0)
tv.append_column(col)
tv.set_property("expander-column", col)

treemodel = store

def _sort_func(model, iter1, iter2):
    """ Sort two iterators by function which gets node objects.
    This is a simple wrapper which prepares node objects and then
    call comparing function. In other case return default value -1
    """
    node_a = model.get_value(iter1, 0)
    node_b = model.get_value(iter2, 0)
    if node_a and node_b:
        sort = cmp(node_a, node_b)
    else:
        sort = -1
    return sort

treemodel.set_sort_func(1, _sort_func)
tv.set_model(treemodel)

def on_child_toggled(treemodel2, path, iter, param=None):
    """ Expand row """
    if not tv.row_expanded(path):
        tv.expand_row(path, True)

treemodel.connect('row-has-child-toggled', on_child_toggled)

tv.set_search_column(1)
tv.set_property("enable-tree-lines", False)
tv.set_rules_hint(False)


#### Drag and drop stuff

dnd_internal_target = ''
dnd_external_targets = {}

def on_drag_fail(widget, dc, result):
    print "Failed dragging", widget, dc, result

def __init_dnd():
    """ Initialize Drag'n'Drop support

    Firstly build list of DND targets:
        * name
        * scope - just the same widget / same application
        * id

    Enable DND by calling enable_model_drag_dest(), 
    enable_model-drag_source()

    It didnt use support from Gtk.Widget(drag_source_set(),
    drag_dest_set()). To know difference, look in PyGTK FAQ:
    http://faq.pygtk.org/index.py?file=faq13.033.htp&req=show
    """
    #defer_select = False

    if dnd_internal_target == '':
        error = 'Cannot initialize DND without a valid name\n'
        error += 'Use set_dnd_name() first'
        raise Exception(error)

    dnd_targets = [(dnd_internal_target, Gtk.TargetFlags.SAME_WIDGET, 0)]
    for target in dnd_external_targets:
        name = dnd_external_targets[target][0]
        dnd_targets.append((name, Gtk.TARGET_SAME_APP, target))

    tv.enable_model_drag_source( Gdk.ModifierType.BUTTON1_MASK,
        dnd_targets, Gdk.DragAction.DEFAULT | Gdk.DragAction.MOVE)

    tv.enable_model_drag_dest(\
        dnd_targets, Gdk.DragAction.DEFAULT | Gdk.DragAction.MOVE)


def on_drag_data_get(treeview, context, selection, info, timestamp):
    """ Extract data from the source of the DnD operation.

    Serialize iterators of selected tasks in format 
    <iter>,<iter>,...,<iter> and set it as parameter of DND """
    print "on_drag_data_get(", treeview, context, selection, info, timestamp

    treeselection = treeview.get_selection()
    model, paths = treeselection.get_selected_rows()
    iters = [model.get_iter(path) for path in paths]
    iter_str = ','.join([model.get_string_from_iter(iter) for iter in iters])
    selection.set(dnd_internal_target, 0, iter_str)
    print "Sending", iter_str

def on_drag_data_received(treeview, context, x, y, selection, info,\
                          timestamp):
    """ Handle a drop situation.

    First of all, we need to get id of node which should accept
    all draged nodes as their new children. If there is no node,
    drop to root node.

    Deserialize iterators of dragged nodes (see self.on_drag_data_get())
    Info parameter determines which target was used:
        * info == 0 => internal DND within this TreeView
        * info > 0 => external DND

    In case of internal DND we just use Tree.move_node().
    In case of external DND we call function associated with that DND
    set by self.set_dnd_external()
    """
    print "on_drag_data_received", treeview, context, x, y, selection, info, timestamp

    model = treeview.get_model()
    destination_iter = None
    destination_tid = None
    drop_info = treeview.get_dest_row_at_pos(x, y)
    if drop_info:
        path, position = drop_info
        destination_iter = model.get_iter(path)
        if destination_iter:
            destination_tid = model.get_value(destination_iter, 0)

    # Get dragged iter as a TaskTreeModel iter
    # If there is no selected task (empty selection.data), 
    # explictly skip handling it (set to empty list)
    if selection.data == '':
        iters = []
    else:
        iters = selection.data.split(',')

    dragged_iters = []
    for iter in iters:
        print "Info", info
        if info == 0:
            try:
                dragged_iters.append(model.get_iter_from_string(iter))
            except ValueError:
                #I hate to silently fail but we have no choice.
                #It means that the iter is not good.
                #Thanks shitty Gtk API for not allowing us to test the string
                print "Shitty iter", iter
                dragged_iter = None

        elif info in dnd_external_targets and destination_tid:
            f = dnd_external_targets[info][1]

            src_model = context.get_source_widget().get_model()
            dragged_iters.append(src_model.get_iter_from_string(iter))


    for dragged_iter in dragged_iters:
        if info == 0:
            if dragged_iter and model.iter_is_valid(dragged_iter):
                dragged_tid = model.get_value(dragged_iter, 0)
                try:
                    row = []
                    for i in range(model.get_n_columns()):
                        row.append(model.get_value(dragged_iter, i))
                    #tree.move_node(dragged_tid, new_parent_id=destination_tid)
                    print "move_after(%s, %s) ~ (%s, %s)" % (dragged_iter, destination_iter, dragged_tid, destination_tid)
                    #model.move_after(dragged_iter, destination_iter)
                    model.insert(destination_iter, -1, row)
                    model.remove(dragged_iter)
                except Exception, e:
                    print 'Problem with dragging: %s' % e
        elif info in dnd_external_targets and destination_tid:    
            source = src_model.get_value(dragged_iter,0)
            # Handle external Drag'n'Drop
            f(source, destination_tid)


dnd_internal_target = 'gtg/task-iter-str'
__init_dnd()
tv.connect('drag_data_get', on_drag_data_get)
tv.connect('drag_data_received', on_drag_data_received)
tv.connect('drag_failed', on_drag_fail)

window.add(tv)
window.show_all()

tv.expand_all()
Gtk.main()

# vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4

我无法正确处理 dnd_data_receive()，因为它没有被调用或者没有收到数据。它总是因以下回调及其参数而失败:

Failed dragging <TreeView object at 0xeb4370 (GtkTreeView at 0xf742a0)> <gtk.gdk.X11DragContext object at 0xf351e0 (GdkX11DragContext at 0xf96ca0)> <enum GTK_DRAG_RESULT_NO_TARGET of type GtkDragResult>

我的问题:如何将第一个脚本移植到 PyGObject (GTK3)，以便可以对 GtkTreeView 进行排序，同时可以拖放行？如何更改处理拖放-drop 回调以正确处理拖放？

最佳答案

首先，您得到的错误似乎与 PyGObject 的版本有关。在使用最新的 Ubuntu 13.04 beta 重新安装我的笔记本电脑之前，我确实重现了类似的错误信息。但是升级后，错误回调变成了类似

on_drag_data_get( <TreeView object at 0x1765870 (GtkTreeView at 0x19120a0)> <gtk.gdk.X11DragContext object at 0x1765aa0 (GdkX11DragContext at 0x1988820)> <GtkSelectionData at 0x7fffb106b760> 0 21962912
Traceback (most recent call last):
  File "dnd_gtk3_org.py", line 116, in on_drag_data_get
    selection.set(dnd_internal_target, 0, iter_str)
  File "/usr/lib/python2.7/dist-packages/gi/types.py", line 113, in function
    return info.invoke(*args, **kwargs)
TypeError: argument type: Expected Gdk.Atom, but got str
on_drag_data_received <TreeView object at 0x1765870 (GtkTreeView at 0x19120a0)> <gtk.gdk.X11DragContext object at 0x1765be0 (GdkX11DragContext at 0x1988940)> 45 77 <GtkSelectionData at 0x7fffb106b6e0> 0 21962912
Traceback (most recent call last):
  File "dnd_gtk3_org.py", line 151, in on_drag_data_received
    if selection.data == '':
AttributeError: 'SelectionData' object has no attribute 'data'

只有两个小问题:

• SelectionData.set() 的第一个参数似乎只能是 Gtk.gdk.Atom 而不是 pygtk 中指定的字符串。
• SelectionData 没有 data 属性，但有一个 get_data() 方法。

下面列出的工作代码片段

#!/usr/bin/python
# -*- coding: utf-8 -*-

from gi.repository import Gtk, Gdk

window = Gtk.Window()
window.set_size_request(300, 200)
window.connect('delete_event', Gtk.main_quit)

# Define Liblarch Tree

store = Gtk.TreeStore(str, str)
store.insert(None, -1, ["A", "Task A"])
store.insert(None, -1, ["B", "Task B"])
store.insert(None, -1, ["C", "Task C"])
d_parent = store.insert(None, -1, ["D", "Task D"])
store.insert(d_parent, -1, ["E", "Task E"])

# Define TreeView in similar way as it happens in GTG/Liblarch_gtk
tv = Gtk.TreeView()

col = Gtk.TreeViewColumn()
col.set_title("Title")
render_text = Gtk.CellRendererText()
col.pack_start(render_text, expand=True)
col.add_attribute(render_text, 'markup', 1)
col.set_resizable(True)
col.set_expand(True)
col.set_sort_column_id(0)
tv.append_column(col)
tv.set_property("expander-column", col)

treemodel = store

def _sort_func(model, iter1, iter2):
    """ Sort two iterators by function which gets node objects.
    This is a simple wrapper which prepares node objects and then
    call comparing function. In other case return default value -1
    """
    node_a = model.get_value(iter1, 0)
    node_b = model.get_value(iter2, 0)
    if node_a and node_b:
        sort = cmp(node_a, node_b)
    else:
        sort = -1
    return sort

treemodel.set_sort_func(1, _sort_func)
tv.set_model(treemodel)

def on_child_toggled(treemodel2, path, iter, param=None):
    """ Expand row """
    if not tv.row_expanded(path):
        tv.expand_row(path, True)

treemodel.connect('row-has-child-toggled', on_child_toggled)

tv.set_search_column(1)
tv.set_property("enable-tree-lines", False)
tv.set_rules_hint(False)


#### Drag and drop stuff

dnd_internal_target = ''
dnd_external_targets = {}

def on_drag_fail(widget, dc, result):
    print "Failed dragging", widget, dc, result

def __init_dnd():
    """ Initialize Drag'n'Drop support

    Firstly build list of DND targets:
        * name
        * scope - just the same widget / same application
        * id

    Enable DND by calling enable_model_drag_dest(), 
    enable_model-drag_source()

    It didnt use support from Gtk.Widget(drag_source_set(),
    drag_dest_set()). To know difference, look in PyGTK FAQ:
    http://faq.pygtk.org/index.py?file=faq13.033.htp&req=show
    """
    #defer_select = False

    if dnd_internal_target == '':
        error = 'Cannot initialize DND without a valid name\n'
        error += 'Use set_dnd_name() first'
        raise Exception(error)

    dnd_targets = [(dnd_internal_target, Gtk.TargetFlags.SAME_WIDGET, 0)]
    for target in dnd_external_targets:
        name = dnd_external_targets[target][0]
        dnd_targets.append((name, Gtk.TARGET_SAME_APP, target))

    tv.enable_model_drag_source( Gdk.ModifierType.BUTTON1_MASK,
        dnd_targets, Gdk.DragAction.DEFAULT | Gdk.DragAction.MOVE)

    tv.enable_model_drag_dest(\
        dnd_targets, Gdk.DragAction.DEFAULT | Gdk.DragAction.MOVE)


def on_drag_data_get(treeview, context, selection, info, timestamp):
    """ Extract data from the source of the DnD operation.

    Serialize iterators of selected tasks in format 
    <iter>,<iter>,...,<iter> and set it as parameter of DND """
    print "on_drag_data_get(", treeview, context, selection, info, timestamp

    treeselection = treeview.get_selection()
    model, paths = treeselection.get_selected_rows()
    iters = [model.get_iter(path) for path in paths]
    iter_str = ','.join([model.get_string_from_iter(iter) for iter in iters])
    selection.set(selection.get_target(), 0, iter_str)
    print "Sending", iter_str

def on_drag_data_received(treeview, context, x, y, selection, info,\
                          timestamp):
    """ Handle a drop situation.

    First of all, we need to get id of node which should accept
    all draged nodes as their new children. If there is no node,
    drop to root node.

    Deserialize iterators of dragged nodes (see self.on_drag_data_get())
    Info parameter determines which target was used:
        * info == 0 => internal DND within this TreeView
        * info > 0 => external DND

    In case of internal DND we just use Tree.move_node().
    In case of external DND we call function associated with that DND
    set by self.set_dnd_external()
    """
    print "on_drag_data_received", treeview, context, x, y, selection, info, timestamp

    model = treeview.get_model()
    destination_iter = None
    destination_tid = None
    drop_info = treeview.get_dest_row_at_pos(x, y)
    if drop_info:
        path, position = drop_info
        destination_iter = model.get_iter(path)
        if destination_iter:
            destination_tid = model.get_value(destination_iter, 0)

    # Get dragged iter as a TaskTreeModel iter
    # If there is no selected task (empty selection.data), 
    # explictly skip handling it (set to empty list)
    data = selection.get_data()
    if data == '':
        iters = []
    else:
        iters = data.split(',')

    dragged_iters = []
    for iter in iters:
        print "Info", info
        if info == 0:
            try:
                dragged_iters.append(model.get_iter_from_string(iter))
            except ValueError:
                #I hate to silently fail but we have no choice.
                #It means that the iter is not good.
                #Thanks shitty Gtk API for not allowing us to test the string
                print "Shitty iter", iter
                dragged_iter = None

        elif info in dnd_external_targets and destination_tid:
            f = dnd_external_targets[info][1]

            src_model = context.get_source_widget().get_model()
            dragged_iters.append(src_model.get_iter_from_string(iter))


    for dragged_iter in dragged_iters:
        if info == 0:
            if dragged_iter and model.iter_is_valid(dragged_iter):
                dragged_tid = model.get_value(dragged_iter, 0)
                try:
                    row = []
                    for i in range(model.get_n_columns()):
                        row.append(model.get_value(dragged_iter, i))
                    #tree.move_node(dragged_tid, new_parent_id=destination_tid)
                    print "move_after(%s, %s) ~ (%s, %s)" % (dragged_iter, destination_iter, dragged_tid, destination_tid)
                    #model.move_after(dragged_iter, destination_iter)
                    model.insert(destination_iter, -1, row)
                    model.remove(dragged_iter)
                except Exception, e:
                    print 'Problem with dragging: %s' % e
        elif info in dnd_external_targets and destination_tid:    
            source = src_model.get_value(dragged_iter,0)
            # Handle external Drag'n'Drop
            f(source, destination_tid)


dnd_internal_target = 'gtg/task-iter-str'
__init_dnd()
tv.connect('drag_data_get', on_drag_data_get)
tv.connect('drag_data_received', on_drag_data_received)
tv.connect('drag_failed', on_drag_fail)

window.add(tv)
window.show_all()

tv.expand_all()
Gtk.main()

# vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4

上面的代码片段与您问题中的代码片段之间的区别是

116c116
<     selection.set(selection.get_target(), 0, iter_str)
---
>     selection.set(dnd_internal_target, 0, iter_str)
151,152c151
<     data = selection.get_data()
<     if data == '':
---
>     if selection.data == '':
155c154
<         iters = data.split(',')
---
>         iters = selection.data.split(',')

此外，在另一个线程中还有另一个GTK+3版本拖放TreeView的例子:unresponsive drag and drop in pygobject

关于python - 如何在 GTK3 中拖放和排序 GtkTreeView？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/13882076/