python - 在运行时替换 QWidget 对象

Question

在我的应用程序中，我必须用自定义的 QLineEdit 替换所有 QLineEdit 元素。为此，有不同的解决方案:

1. 修改从 pyuic4 生成的 py 文件，并将所有 QLineEdit 对象替换为我的一个 LineEdit。这个解决方案并不是最好的，因为每次运行 pyuic4 时，我都会丢失对生成的输出文件所做的修改。
2. 编写一个新类，在我的窗口或对话框中递归搜索 QLineEdit 小部件类型，并将其替换为我的一个 LineEdit。这个解决方案要好得多。它允许我对其他对象执行相同的操作或根据需要扩展它，而无需关心对话框或窗口。

到目前为止，我可以编写一个模块(WidgetReplacer)，它递归地搜索 QGridLayout 项目并搜索是否有 QLineEdit 子项。如果是，那就换成我的。

问题是，当我尝试访问我的 LineEdit 对象之一时，出现以下错误:

RuntimeError: wrapped C/C++ object of type QLineEdit has been deleted

如果我查看输出，我会注意到修改后的 QLineEdit 对象具有旧的 id:

old qt_obj <PyQt4.QtGui.QLineEdit object at 0x0543C930>
Replaced txt_line_1 with LineEdit
new qt_obj <LineEdit.LineEdit object at 0x0545B4B0>
----------------------------------
...
----------------------------------
<PyQt4.QtGui.QLineEdit object at 0x0543C930>

问题

为什么会出现这种情况？如何在运行时替换 QWidgets？

<小时/>

更新

这里有一些有关对象包装的其他详细信息:在模块 WidgetReplace 中，如果我转储 QEditLine 和 LineEdit 对象，我会得到:

<PyQt4.QtGui.QLineEdit object at 0x05378618>
    Reference count: 7
    Address of wrapped object: 051FAC40
    Created by: Python
    To be destroyed by: C/C++
    Parent wrapper: <PyQt4.QtGui.QGridLayout object at 0x05378588>
    Next sibling wrapper: NULL
    Previous sibling wrapper: <PyQt4.QtGui.QLabel object at 0x05378930>
    First child wrapper: NULL

和

<LineEdit.LineEdit object at 0x05378978>
    Reference count: 3
    Address of wrapped object: 051FAC40
    Created by: Python
    To be destroyed by: C/C++
    Parent wrapper: <__main__.Dialog object at 0x0535FBB8>
    Next sibling wrapper: <PyQt4.QtGui.QGridLayout object at 0x05378780>
    Previous sibling wrapper: NULL
    First child wrapper: NULL

相反，如果我从主窗口转储行编辑，我会得到关注，它代表已删除的 QLineEdit 对象:

<PyQt4.QtGui.QLineEdit object at 0x05378618>
    Reference count: 2
    Address of wrapped object: 00000000
    Created by: Python
    To be destroyed by: C/C++
    Parent wrapper: NULL
    Next sibling wrapper: NULL
    Previous sibling wrapper: NULL
    First child wrapper: NULL

<小时/>

这是我的代码

对话框ui 和生成文件可以从 DropBox dialog.ui and dialog.py 下载

主要

import sys
from PyQt4.QtGui import QDialog, QApplication
from dialog import Ui_Form
from WidgetReplacer import WidgetReplacer

class Dialog(QDialog, Ui_Form):

    def __init__(self, parent = None):
        super(Dialog, self).__init__(parent)

        # Set up the user interface from Designer.
        self.setupUi(self)
        WidgetReplacer().replace_all_qlineedit(self)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = Dialog()

    window.show()

    print window.txt_line_1
    window.txt_line_1.setText("Hello Text 1")

    sys.exit(app.exec_())

行编辑

from PyQt4.QtGui import QLineEdit, QValidator, QPalette
from PyQt4 import QtCore

class LineEdit(QLineEdit):

    def __init__(self, parent=None):
        super(LineEdit, self).__init__(parent)

        self.color_red = QPalette()
        self.color_red.setColor(QPalette.Text, QtCore.Qt.red)

        self.color_black = QPalette()
        self.color_black.setColor(QPalette.Text, QtCore.Qt.red)

        # Make connections
        self.textChanged.connect(self.verify_text)

    def verify_text(self, text):
        validator = self.validator()
        is_valid = QValidator.Acceptable

        if validator is not None:
            is_valid = validator.validate(text, 0)

        if is_valid == QValidator.Acceptable:
            self.setPalette(self.color_black)
        elif is_valid in [QValidator.Invalid, QValidator.Intermediate]:
            self.setPalette(self.color_red)

WidgetReplacer

import sip
from LineEdit import LineEdit
from PyQt4.QtCore import QRegExp
from PyQt4 import QtGui

class WidgetReplacer():

    def __init__(self):
        pass

    def replace_all_qlineedit(self, qt_dlg):
        children = self._get_all_gridlayout(qt_dlg)

        items = []
        for child in children:
            new_items = self._find_all_obj_in_layout(child, QtGui.QLineEdit)
            items.extend(new_items)

        for item in items:
            layout = item[0]
            row = item[1]
            column = item[2]
            qt_obj = item[3]
            self._replace_qlineedit_from_gridlayout(qt_dlg, qt_obj,
                                                    layout, row, column)

    def _get_all_gridlayout(self, qt_dlg):
        return qt_dlg.findChildren(QtGui.QGridLayout, QRegExp("gridLayout_[0-9]"))

    def _find_all_obj_in_layout(self, layout, qt_type):
        # Output list format:
        # layout, row, col, qt_obj,
        objects = []
        if type(layout) == QtGui.QGridLayout:
            layout_cols = layout.columnCount()
            layout_rows = layout.rowCount()
            for i in range(layout_rows):
                for j in range(layout_cols):
                    item = layout.itemAtPosition(i, j)
#                    print "item(",i, j, "):", item

                    if type(item) == QtGui.QWidgetItem:
                        if type(item.widget()) == qt_type:
                            new_obj = [layout, i, j, item.widget()]
                            objects.append(new_obj)

        elif type(layout) in [QtGui.QHBoxLayout, QtGui.QVBoxLayout]:
            raise SyntaxError("ERROR: Find of Qt objects in QHBoxLayout or QVBoxLayout still not supported")
#            for i in range(layout.count()):
#                item = layout.itemAt(i)

        return objects

    def _replace_qlineedit_from_gridlayout(self, parent, qt_obj, layout, row, column):
        print "old qt_obj", qt_obj
        obj_name = qt_obj.objectName()
        layout.removeWidget(qt_obj)
        sip.delete(qt_obj)
        qt_obj = LineEdit(parent)
        qt_obj.setObjectName(obj_name)

        layout.addWidget(qt_obj, row, column)
        print "Replaced", obj_name, "with LineEdit"

        print "new qt_obj", qt_obj
        print "----------------------------------"

Answer 1

不要在运行时替换小部件:在 Qt Designer 中升级小部件，以便在生成 GUI 模块时自动将行编辑替换为您的自定义类。

以下是如何提升小部件以使用自定义类:

在 Qt Designer 中，选择要替换的所有行编辑，然后右键单击它们并选择“升级到...”。在对话框中，将“升级的类名称”设置为“LineEdit”，并将“头文件”设置为包含此类的模块的 python 导入路径(例如 myapp.LineEdit)。然后单击“添加”和“升级”，您将在对象检查器 Pane 中看到类从“QLineEdit”更改为“LineEdit”。

现在，当您使用 pyuic 重新生成 ui 模块时，您应该看到它使用您的自定义 LineEdit 类，并且文件底部会有一个额外的行，如下所示:

    from myapp.LineEdit import LineEdit