PyQT实现扩展窗口，更多/隐藏

如图，点击More按钮后显示和隐藏更多的项。

#!/usr/bin/env python

#############################################################################

##

## Copyright (C) 2013 Riverbank Computing Limited.

## Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).

## All rights reserved.

##

## This file is part of the examples of PyQt.

##

## $QT_BEGIN_LICENSE:BSD$

## You may use this file under the terms of the BSD license as follows:

##

## "Redistribution and use in source and binary forms, with or without

## modification, are permitted provided that the following conditions are

## met:

##   * Redistributions of source code must retain the above copyright

##     notice, this list of conditions and the following disclaimer.

##   * Redistributions in binary form must reproduce the above copyright

##     notice, this list of conditions and the following disclaimer in

##     the documentation and/or other materials provided with the

##     distribution.

##   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor

##     the names of its contributors may be used to endorse or promote

##     products derived from this software without specific prior written

##     permission.

##

## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

## OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

## SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

## DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

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## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."

## $QT_END_LICENSE$

##

#############################################################################

from PyQt5.QtCore import Qt

from PyQt5.QtWidgets import (QApplication, QCheckBox, QDialog,

        QDialogButtonBox, QGridLayout, QHBoxLayout, QLabel, QLayout, QLineEdit,

        QPushButton, QVBoxLayout, QWidget)

class FindDialog(QDialog):

    def __init__(self, parent=None):

        super(FindDialog, self).__init__(parent)

        label = QLabel("Find &what:")

        lineEdit = QLineEdit()

        label.setBuddy(lineEdit)

        caseCheckBox = QCheckBox("Match &case")

        fromStartCheckBox = QCheckBox("Search from &start")

        fromStartCheckBox.setChecked(True)

        findButton = QPushButton("&Find")

        findButton.setDefault(True)

        moreButton = QPushButton("&More")

        moreButton.setCheckable(True)

        moreButton.setAutoDefault(False)

        extension = QWidget()

        wholeWordsCheckBox = QCheckBox("&Whole words")

        backwardCheckBox = QCheckBox("Search &backward")

        searchSelectionCheckBox = QCheckBox("Search se&lection")

        buttonBox = QDialogButtonBox(Qt.Vertical)

        buttonBox.addButton(findButton, QDialogButtonBox.ActionRole)

        buttonBox.addButton(moreButton, QDialogButtonBox.ActionRole)

        moreButton.toggled.connect(extension.setVisible)

        extensionLayout = QVBoxLayout()

        extensionLayout.setContentsMargins(0, 0, 0, 0)

        extensionLayout.addWidget(wholeWordsCheckBox)

        extensionLayout.addWidget(backwardCheckBox)

        extensionLayout.addWidget(searchSelectionCheckBox)

        extension.setLayout(extensionLayout)

        topLeftLayout = QHBoxLayout()

        topLeftLayout.addWidget(label)

        topLeftLayout.addWidget(lineEdit)

        leftLayout = QVBoxLayout()

        leftLayout.addLayout(topLeftLayout)

        leftLayout.addWidget(caseCheckBox)

        leftLayout.addWidget(fromStartCheckBox)

        mainLayout = QGridLayout()

        #关键性的参数设置

        mainLayout.setSizeConstraint(QLayout.SetFixedSize)

        mainLayout.addLayout(leftLayout, 0, 0)

        mainLayout.addWidget(buttonBox, 0, 1)

        mainLayout.addWidget(extension, 1, 0, 1, 2)

        mainLayout.setRowStretch(2, 1)

        self.setLayout(mainLayout)

        self.setWindowTitle("Extension")

        extension.hide()

if __name__ == '__main__':

    import sys

    app = QApplication(sys.argv)

    dialog = FindDialog()

    dialog.show()

    sys.exit(app.exec_())

#关键性的参数设置

 mainLayout.setSizeConstraint(QLayout.SetFixedSize)