pyqt5 QScrollArea继承

Question

我很难理解如何在 PyQt5 中使用滚动条。我有一个任意布局来试验，这只是一些颜色块。我希望颜色布局具有最小尺寸，并且当 window 小于该尺寸时，会出现滚动条（或者滚动条一直存在）。我找到了这个例子：

PyQt: Put scrollbars in this

并将其更改为与 PyQt5 一起使用：

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

from PyQt5 import QtCore, QtGui
from PyQt5.QtWidgets import QDialog, QApplication, QPushButton, QScrollArea, QVBoxLayout, QWidget
class myDialog(QDialog):
    _buttons = 0

    def __init__(self, parent=None):
        super(myDialog, self).__init__(parent)
        self.pushButton = QPushButton(self)
        self.pushButton.setText("Add Button!")
        self.pushButton.clicked.connect(self.on_pushButton_clicked)
        self.scrollArea = QScrollArea(self)
        self.scrollArea.setWidgetResizable(True)
        self.scrollAreaWidgetContents = QWidget(self.scrollArea)
        self.scrollAreaWidgetContents.setGeometry(QtCore.QRect(0, 0, 380, 247))
        self.scrollArea.setWidget(self.scrollAreaWidgetContents)
        self.verticalLayout = QVBoxLayout(self)
        self.verticalLayout.addWidget(self.pushButton)
        self.verticalLayout.addWidget(self.scrollArea)
        self.verticalLayoutScroll = QVBoxLayout(self.scrollAreaWidgetContents)
'''
verticalLayoutScroll is a child of scrollAreaWidgetContents
scrollAreaWidgetContents is a child of scrollArea
scrollArea is child of self

verticalLayout is also a child of self has the widgets pushButton and scrollArea
'''
    @QtCore.pyqtSlot()
    def on_pushButton_clicked(self):
        self._buttons  += 1
        pustButtonName = u"Button {0}".format(self._buttons)

        pushButton = QPushButton(self.scrollAreaWidgetContents)
        pushButton.setText(pustButtonName)

        self.verticalLayoutScroll.addWidget(pushButton)


if __name__ == "__main__":
    import sys
    app = QApplication(sys.argv)
    app.setApplicationName('myDialog')
    main = myDialog()
    main.show()
    sys.exit(app.exec_())

这是我的代码：

    # -*- coding: utf-8 -*-
"""
Created on Mon Jan 15 07:37:28 2018

@author: Erik
"""
import sys
from PyQt5.QtWidgets import (QApplication, QWidget, QSlider, QPushButton, 
QMainWindow, QAction, qApp,
    QLCDNumber, QGridLayout, QLabel, QLineEdit, QVBoxLayout, QHBoxLayout, 
QSizePolicy, QScrollArea, QLayout)
from PyQt5.QtGui import QIcon, QColor, QPalette
from PyQt5.QtCore import Qt, QSize, QRect

class Color(QWidget):

    def __init__(self, color, *args, **kwargs):
        super(Color, self).__init__(*args, **kwargs)
        self.setAutoFillBackground(True)

        palette = self.palette()
        palette.setColor(QPalette.Window, QColor(color))
        self.setPalette(palette)

class Color2(QWidget):

    def __init__(self, color, *args, **kwargs):
        super(Color2, self).__init__(*args, **kwargs)
        self.setAutoFillBackground(True)
        palette = self.palette()
        palette.setColor(QPalette.Window, QColor(color))
        self.setPalette(palette)

    def sizeHint(self):
        return QSize(150,150)

class MainWindow(QMainWindow):

    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)

        self.setWindowTitle("My Awesome App")

        size = QSizePolicy(QSizePolicy.Maximum, QSizePolicy.Maximum)

        layout = QVBoxLayout()
        layout2 = QVBoxLayout()
        brw = Color2('brown')
        brw.setSizePolicy(size)
        layout2.addWidget(brw)
        layout2.addWidget(Color('black'))
        layout2.setStretch(1,2)
        layout2.addWidget(Color('cyan'))
        layout2.setStretch(2, 1)

        layout.addWidget(Color('red'))
        layout.addWidget(Color('blue'))
        layout.addWidget(Color('green'))


        self.scrollArea = QScrollArea(self)
        self.scrollArea.setWidgetResizable(True)
        self.scrollAreaWidgetContents = QWidget(self.scrollArea)
        self.scrollAreaWidgetContents.setGeometry(QRect(0, 0, 600, 500))   
        self.scrollArea.setWidget(self.scrollAreaWidgetContents)
        self.scrollAreaWidgetContents.setMinimumSize(QSize(500, 500))

        self.scrollLayout = QVBoxLayout(self.scrollAreaWidgetContents)
        #self.scrollLayout.setSizeConstraint(QLayout.SetMinimumSize) #2
        self.mainLayout = QHBoxLayout()
        self.mainLayout.addWidget(Color('purple'))
        self.mainLayout.addWidget(Color('yellow'))
        self.mainLayout.addWidget(Color('orange'))
        self.mainLayout.addLayout(layout2)
        self.mainLayout.addLayout(layout)
        self.scrollLayout.addLayout(self.mainLayout)

        self.show()


if __name__ == '__main__':

    app = QApplication(sys.argv)
    ex = MainWindow()
    sys.exit(app.exec_())

我几乎看不到 scrollArea 中的颜色。在上面的第一个代码块中，我不理解我在注释块中描述的必要的继承结构。我是否需要扩展布局 class 来设置最小尺寸？ https://doc.qt.io/qt-5/qlayoutitem.html#minimumSize https://doc.qt.io/qt-5/qscrollarea.html#details 的 "Size Hints and Layouts" 部分有何相关性？
谢谢。

Answer 1

问题是你没有将QScrollArea设置为centralWidget。

class MainWindow(QMainWindow):
    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)
        self.setWindowTitle("My Awesome App")

        size = QSizePolicy(QSizePolicy.Maximum, QSizePolicy.Maximum)

        layout = QVBoxLayout()
        layout2 = QVBoxLayout()
        brw = Color2('brown')
        brw.setSizePolicy(size)
        layout2.addWidget(brw)
        layout2.addWidget(Color('black'))
        layout2.setStretch(1,2)
        layout2.addWidget(Color('cyan'))
        layout2.setStretch(2, 1)

        layout.addWidget(Color('red'))
        layout.addWidget(Color('blue'))
        layout.addWidget(Color('green'))

        self.scrollArea = QScrollArea()
        # set CentralWidget
        self.setCentralWidget(self.scrollArea)

        self.scrollArea.setWidgetResizable(True)
        self.scrollAreaWidgetContents = QWidget(self.scrollArea)
        self.scrollAreaWidgetContents.setGeometry(QRect(0, 0, 600, 500))   
        self.scrollArea.setWidget(self.scrollAreaWidgetContents)
        self.scrollAreaWidgetContents.setMinimumSize(QSize(500, 500))

        self.scrollLayout = QVBoxLayout(self.scrollAreaWidgetContents)
        #self.scrollLayout.setSizeConstraint(QLayout.SetMinimumSize) #2
        self.mainLayout = QHBoxLayout()
        self.mainLayout.addWidget(Color('purple'))
        self.mainLayout.addWidget(Color('yellow'))
        self.mainLayout.addWidget(Color('orange'))
        self.mainLayout.addLayout(layout2)
        self.mainLayout.addLayout(layout)
        self.scrollLayout.addLayout(self.mainLayout)

        self.show()

pyqt5 QScrollArea继承

pyqt5 QScrollArea inheritance

python

pyqt

qscrollarea

pyqt5