在动态GUI中从Gtk视口/滚动窗口中删除小部件

Question

我正在构建一个GUI（GTK3的Python绑定），其中一个Gtk滚动窗口（来自Glade）可以包含不同的树视图。该程序启动时会出现一个空窗口，第一次使用的是：

 self.scrolled_window.add_with_viewport(treeview)
 self.main_window.show_all()

编辑：测试程序的图片（参见下面的来源）：

第二次出现以下错误：

（main.py:15905）：Gtk-CRITICAL **：gtk_scrolled_window_add_with_viewport：断言'gtk_bin_get_child（GTK_BIN（child_widget））== NULL'失败

我认为我可能需要先清空视口或滚动窗口，但不知道是怎么做的，也找不到任何文档。

编辑：使用 self.scrolled_window.remove（self.scrolled_window.get_child（））时，我看不到启动时的数据集，并显示错误消息切换图层时。

编辑：我再次更新了代码，因此示例数据从一开始就存在。

林间文件（test_project.glade）：

<?xml version="1.0" encoding="UTF-8"?>
<!-- Generated with glade 3.16.1 -->
<interface>
  <requires lib="gtk+" version="3.10"/>
  <object class="GtkWindow" id="window1">
    <property name="can_focus">False</property>
    <property name="default_width">440</property>
    <property name="default_height">250</property>
    <signal name="destroy" handler="on_window1_destroy" swapped="no"/>
    <child>
      <object class="GtkBox" id="box1">
        <property name="visible">True</property>
        <property name="can_focus">False</property>
        <property name="orientation">vertical</property>
        <child>
          <object class="GtkScrolledWindow" id="scrolledwindow1">
            <property name="visible">True</property>
            <property name="can_focus">True</property>
            <property name="shadow_type">in</property>
            <child>
              <placeholder/>
            </child>
          </object>
          <packing>
            <property name="expand">True</property>
            <property name="fill">True</property>
            <property name="position">0</property>
          </packing>
        </child>
        <child>
          <object class="GtkScrolledWindow" id="scrolledwindow2">
            <property name="visible">True</property>
            <property name="can_focus">True</property>
            <property name="shadow_type">in</property>
            <child>
              <placeholder/>
            </child>
          </object>
          <packing>
            <property name="expand">True</property>
            <property name="fill">True</property>
            <property name="position">1</property>
          </packing>
        </child>
        <child>
          <object class="GtkBox" id="box2">
            <property name="visible">True</property>
            <property name="can_focus">False</property>
            <child>
              <object class="GtkButton" id="add_layer">
                <property name="label" translatable="yes">add layer</property>
                <property name="visible">True</property>
                <property name="can_focus">True</property>
                <property name="receives_default">True</property>
                <signal name="clicked" handler="on_add_layer_clicked" swapped="no"/>
              </object>
              <packing>
                <property name="expand">False</property>
                <property name="fill">True</property>
                <property name="position">0</property>
              </packing>
            </child>
            <child>
              <object class="GtkButton" id="add_data">
                <property name="label" translatable="yes">add data</property>
                <property name="name">add_data</property>
                <property name="visible">True</property>
                <property name="can_focus">True</property>
                <property name="receives_default">True</property>
                <signal name="clicked" handler="on_add_data_clicked" swapped="no"/>
              </object>
              <packing>
                <property name="expand">False</property>
                <property name="fill">True</property>
                <property name="position">1</property>
              </packing>
            </child>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">2</property>
          </packing>
        </child>
      </object>
    </child>
  </object>
</interface>

python代码：

#!/usr/bin/python3

from gi.repository import Gtk
import random

class BottomTreeView(Gtk.TreeView):
    def __init__(self, store):
        Gtk.TreeView.__init__(store)
        self.store = store

        renderer = Gtk.CellRendererText()
        column = Gtk.TreeViewColumn("Dataset", renderer, text=0)
        self.append_column(column)

        for x in range(10):
            self.store.append(None, [str(random.random())])

class MainWindow(object):
    def __init__(self, builder):
        self.main_window = builder.get_object("window1")
        self.sw1 = builder.get_object("scrolledwindow1")
        self.sw2 = builder.get_object("scrolledwindow2")
        self.layernumber = 0

        self.topstore = Gtk.TreeStore(str, object)
        self.topview = Gtk.TreeView(self.topstore)
        renderer1 = Gtk.CellRendererText()
        column1 = Gtk.TreeViewColumn("Name", renderer1, text=0)
        self.topview.append_column(column1)
        self.sw1.add_with_viewport(self.topview)

        #Adding test data in a dumb way
        self.store1 = Gtk.TreeStore(str)
        for x in range(10):
            self.store1.append(None, [str(random.random())])
        self.view1 = Gtk.TreeView(self.store1)
        self.rend1 = Gtk.CellRendererText()
        self.col1 = Gtk.TreeViewColumn("Dataset", self.rend1, text=0)
        self.view1.append_column(self.col1)
        self.sw2.add_with_viewport(self.view1)
        self.topstore.append(None, ["Layer 1", self.view1])

        self.store2 = Gtk.TreeStore(str)
        for x in range(10):
            self.store2.append(None, [str(random.random())])
        self.view2 = Gtk.TreeView(self.store2)
        self.rend2 = Gtk.CellRendererText()
        self.col2 = Gtk.TreeViewColumn("Dataset", self.rend2, text=0)
        self.view2.append_column(self.col2)
        self.topstore.append(None, ["Layer 2", self.view2])

        self.select = self.topview.get_selection()
        self.select.connect("changed", self.on_tree_selection_changed)
        self.main_window.show_all()

    def on_add_layer_clicked(self, widget):
        self.layernumber += 1
        store = Gtk.TreeStore(str)
        bottom = BottomTreeView(store)
        self.topstore.append(None, [str(self.layernumber), bottom])

    def on_add_data_clicked(self, widget):
        self.selection = self.topview.get_selection()
        model, treeiter = self.selection.get_selected()
        print("Adding data to {0}".format(model[treeiter][0]))
        datasheet = model[treeiter][1]
        datasheet.store.append(None, [str(random.random())])

    def on_window1_destroy(self, widget):
        Gtk.main_quit()

    def on_tree_selection_changed(self, selection):
        print("\n>>> Selection changed")
        model, treeiter = selection.get_selected()
        print(">>> Model: {0}, Treeiter: {1}".format(model, treeiter))
        if treeiter != None:
             print(">>> You selected Layer {0}.".format(model[treeiter][1]))
             tree_obj = model[treeiter][1]
             #The following lines mess up the program from the startup
             #self.sw2.remove(self.sw2.get_child())
             #self.sw2.add_with_viewport(tree_obj)
             #self.main_window.show_all()

def main():
    builder = Gtk.Builder()
    objects = builder.add_objects_from_file("test_project.glade",
         ("window1", ""))

    window_instance = MainWindow(builder)
    builder.connect_signals(window_instance)
    Gtk.main()

if __name__ == "__main__":
     main()

Answer 1

要清除滚动窗口，请执行以下操作：

self.scrolled_window.remove(self.scrolled_window.get_child())

Answer 2

在ptomato的回答之后，我意识到我正在使用：

添加TreeViews

  self.scrolled_window.add_with_viewport(some_treeview)

由于某种原因， scrolled_window.remove（）函数不喜欢视口。相反，应该使用：

  self.scrolled_window.add(some_treeview)

它可能有意义，因为文档说明：

  

如果窗口小部件具有本机滚动功能，例如Gtk.TextView，Gtk.TreeView或Gtk.IconView，则可以使用Gtk.Container.add（）将其添加到Gtk.ScrolledWindow。如果窗口小部件没有，则必须先将窗口小部件添加到Gtk.Viewport，然后将视口添加到滚动窗口。

（资料来源：https://lazka.github.io/pgi-docs/Gtk-3.0/classes/Viewport.html）

因为Gtk.TreeView已经可滚动，所以不应该进入单独的Gtk.Viewport小部件。

工作示例

我清理了上面的例子，它现在完全正常运作：

Glade文件

<?xml version="1.0" encoding="UTF-8"?>
<!-- Generated with glade 3.16.1 -->
<interface>
  <requires lib="gtk+" version="3.10"/>
  <object class="GtkWindow" id="window1">
    <property name="can_focus">False</property>
    <property name="default_width">800</property>
    <property name="default_height">600</property>
    <signal name="destroy" handler="on_window1_destroy" swapped="no"/>
    <child>
      <object class="GtkBox" id="box1">
        <property name="visible">True</property>
        <property name="can_focus">False</property>
        <property name="orientation">vertical</property>
        <child>
          <object class="GtkBox" id="box2">
            <property name="visible">True</property>
            <property name="can_focus">False</property>
            <child>
              <object class="GtkScrolledWindow" id="scrolledwindow1">
                <property name="visible">True</property>
                <property name="can_focus">True</property>
                <property name="shadow_type">in</property>
                <child>
                  <placeholder/>
                </child>
              </object>
              <packing>
                <property name="expand">True</property>
                <property name="fill">True</property>
                <property name="position">0</property>
              </packing>
            </child>
            <child>
              <object class="GtkScrolledWindow" id="scrolledwindow2">
                <property name="visible">True</property>
                <property name="can_focus">True</property>
                <property name="shadow_type">in</property>
                <child>
                  <placeholder/>
                </child>
              </object>
              <packing>
                <property name="expand">True</property>
                <property name="fill">True</property>
                <property name="position">1</property>
              </packing>
            </child>
          </object>
          <packing>
            <property name="expand">True</property>
            <property name="fill">True</property>
            <property name="position">0</property>
          </packing>
        </child>
        <child>
          <object class="GtkBox" id="box3">
            <property name="visible">True</property>
            <property name="can_focus">False</property>
            <child>
              <object class="GtkButton" id="add_layer">
                <property name="label" translatable="yes">add layer</property>
                <property name="visible">True</property>
                <property name="can_focus">True</property>
                <property name="receives_default">True</property>
                <signal name="clicked" handler="on_add_layer_clicked" swapped="no"/>
              </object>
              <packing>
                <property name="expand">False</property>
                <property name="fill">True</property>
                <property name="position">0</property>
              </packing>
            </child>
            <child>
              <object class="GtkButton" id="add_data">
                <property name="label" translatable="yes">add data</property>
                <property name="name">add_data</property>
                <property name="visible">True</property>
                <property name="can_focus">True</property>
                <property name="receives_default">True</property>
                <signal name="clicked" handler="on_add_data_clicked" swapped="no"/>
              </object>
              <packing>
                <property name="expand">False</property>
                <property name="fill">True</property>
                <property name="position">1</property>
              </packing>
            </child>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">1</property>
          </packing>
        </child>
      </object>
    </child>
  </object>
</interface>

Python文件

#!/usr/bin/python3

from gi.repository import Gtk
import random

class LayerTreeView(Gtk.TreeView):
    def __init__(self, store):
        Gtk.TreeView.__init__(self, store)
        renderer = Gtk.CellRendererText()
        column = Gtk.TreeViewColumn("Name", renderer, text=0)
        self.append_column(column)

class DataTreeView(Gtk.TreeView):
    def __init__(self, store):
        Gtk.TreeView.__init__(self, store)
        self.store = store
        renderer = Gtk.CellRendererText()
        column = Gtk.TreeViewColumn("Dataset", renderer, text=0)
        self.append_column(column)

        for x in range(10):
            self.store.append(None, [str(random.random())])

class MainWindow(object):
    def __init__(self, builder):
        self.main_window = builder.get_object("window1")
        self.sw1 = builder.get_object("scrolledwindow1")
        self.sw2 = builder.get_object("scrolledwindow2")
        self.layernumber = 1

        #Initializing top TreeStore and TreeView
        #First object is the store, second is the view of the bottom data-view
        self.topstore = Gtk.TreeStore(str, object, object)
        self.topview = LayerTreeView(self.topstore)
        self.sw1.add(self.topview)

        #Adding some testdata
        for x in range(3):
            datastore = Gtk.TreeStore(str)
            dataview = DataTreeView(datastore)
            layername = "Layer {0}".format(self.layernumber)
            self.layernumber += 1
            self.topstore.append(None, [layername, datastore, dataview])

        self.select = self.topview.get_selection()
        self.select.connect("changed", self.on_tree_selection_changed)
        self.main_window.show_all()

    def on_add_layer_clicked(self, widget):
        datastore = Gtk.TreeStore(str)
        dataview = DataTreeView(datastore)
        layername = "Layer {0}".format(self.layernumber)
        self.layernumber += 1
        self.topstore.append(None, [layername, datastore, dataview])

    def on_add_data_clicked(self, widget):
        self.selection = self.topview.get_selection()
        model, treeiter = self.selection.get_selected()
        if treeiter != None:
            data_object = model[treeiter][1]
            data_object.append(None, [str(random.random())])

    def on_window1_destroy(self, widget):
        Gtk.main_quit()

    def on_tree_selection_changed(self, selection):
        model, treeiter = selection.get_selected()
        if treeiter != None:
            treeview_object = model[treeiter][2]
            child = self.sw2.get_child()
            if child != None:
                self.sw2.remove(self.sw2.get_child())
            self.sw2.add(treeview_object)
            self.main_window.show_all()

def main():
    builder = Gtk.Builder()
    objects = builder.add_objects_from_file("treeview_switcher.glade",
         ("window1", ""))

    window_instance = MainWindow(builder)
    builder.connect_signals(window_instance)
    Gtk.main()

if __name__ == "__main__":
     main()