在 PyQt 中动态添加和删除小部件 [英] dynamically adding and removing widgets in PyQt

问题描述

使用 PyQt，我正在尝试创建一个可以动态添加或删除小部件的界面.我想为将要添加或删除的小部件定义一个单独的类.我似乎无法获得我实例化的小部件以显示在主界面内.这是我正在使用的代码:

using PyQt, I am trying to create an interface for which I can add or remove widget dynamically. I want to define a separate class for the widget that will be added or removed. I can't seem to be able to get the widget that I instantiate to display inside the main interface. Here is the code I am using:

from PyQt4 import QtGui, QtCore
import sys

class Main(QtGui.QMainWindow):
    def __init__(self, parent = None):
        super(Main, self).__init__(parent)

        # central widget
        self.centralWidget = QtGui.QWidget(self)

        # main layout
        self.vLayout = QtGui.QVBoxLayout(self.centralWidget)

        # main button
        self.pButton_add = QtGui.QPushButton(self.centralWidget)
        self.pButton_add.setText('button to add other widgets')

        # scroll area
        self.scrollArea = QtGui.QScrollArea(self.centralWidget)
        self.scrollArea.setWidgetResizable(True)

        # scroll area widget contents
        self.scrollAreaWidgetContents = QtGui.QWidget(self.scrollArea)

        # scroll area widget contents - layout
        self.formLayout = QtGui.QFormLayout(self.scrollAreaWidgetContents)

        self.scrollArea.setWidget(self.scrollAreaWidgetContents)

        # add all main to the main vLayout
        self.vLayout.addWidget(self.pButton_add)
        self.vLayout.addWidget(self.scrollArea)
        # set central widget
        self.setCentralWidget(self.centralWidget)
        # connections
        self.pButton_add.clicked.connect(self.addWidget)


    def addWidget(self):
        z = Test(self.scrollAreaWidgetContents)
        count = self.formLayout.rowCount()
        self.formLayout.setWidget(count, QtGui.QFormLayout.LabelRole, z)


class Test(QtGui.QWidget):
  def __init__( self, parent):
      super(Test, self).__init__(parent)

      self.pushButton = QtGui.QPushButton(self)


app = QtGui.QApplication(sys.argv)
myWidget = Main()
myWidget.show()
app.exec_()

问题是，当我在我的addWidget"方法中使用下面的代码时，它完全符合我的要求，但类方法似乎不起作用.

the thing is, when I use the below code inside my 'addWidget' method, it exactly does what I want it to do, but the the class method doesn't seem to work.

z = QtGui.QPushButton(self.scrollAreaWidgetContents)
count = self.formLayout.rowCount())
self.formLayout.setWidget(count, QtGui.QFormLayout.LabelRole, z)

我想知道为什么 z = Test() 没有产生任何结果?有任何想法吗?谢谢！

I wonder why the z = Test() is not yielding any results? Any ideas? Thanks!

推荐答案

实际上，它确实有效.问题是，您的 Test 小部件有一个 QPushButton 没有任何布局管理.所以它不能在考虑按钮的情况下计算它的 minimumSize.当您将该小部件放在布局中时，它只会缩小到 0(因为 QWidget 没有默认的 minimumSize)并且您看不到任何东西.

Actually, it does work. Problem is, your Test widget has a QPushButton without any layout management. So it can't calculate its minimumSize with taking the button into consideration. When you put that widget in a layout, it just shrinks to 0 (since a QWidget has no default minimumSize) and you don't see anything.

您有两种选择，要么手动管理布局并进入不必要的痛苦世界，要么依赖布局管理器.一般来说，你应该选择后者.

You have two choices, either you manually manage layout and enter a needless world of pain, or you rely on layout managers. In general, you should prefer the latter.

我会像这样重新编写您的脚本(虽然我不确定您为什么使用 QFormLayout，但我保持原样.):

I would re-write your script like this (Although I'm not sure why you use QFormLayout, I leave it as it is.):

from PyQt4 import QtGui, QtCore
import sys

class Main(QtGui.QMainWindow):
    def __init__(self, parent = None):
        super(Main, self).__init__(parent)

        # main button
        self.addButton = QtGui.QPushButton('button to add other widgets')
        self.addButton.clicked.connect(self.addWidget)

        # scroll area widget contents - layout
        self.scrollLayout = QtGui.QFormLayout()

        # scroll area widget contents
        self.scrollWidget = QtGui.QWidget()
        self.scrollWidget.setLayout(self.scrollLayout)

        # scroll area
        self.scrollArea = QtGui.QScrollArea()
        self.scrollArea.setWidgetResizable(True)
        self.scrollArea.setWidget(self.scrollWidget)

        # main layout
        self.mainLayout = QtGui.QVBoxLayout()

        # add all main to the main vLayout
        self.mainLayout.addWidget(self.addButton)
        self.mainLayout.addWidget(self.scrollArea)

        # central widget
        self.centralWidget = QtGui.QWidget()
        self.centralWidget.setLayout(self.mainLayout)

        # set central widget
        self.setCentralWidget(self.centralWidget)

    def addWidget(self):
        self.scrollLayout.addRow(Test())


class Test(QtGui.QWidget):
  def __init__( self, parent=None):
      super(Test, self).__init__(parent)

      self.pushButton = QtGui.QPushButton('I am in Test widget')

      layout = QtGui.QHBoxLayout()
      layout.addWidget(self.pushButton)
      self.setLayout(layout)



app = QtGui.QApplication(sys.argv)
myWidget = Main()
myWidget.show()
app.exec_()

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