Qcombobox 在 PyQt 中，如何在一个组合框中设置选项，这取决于其他组合框的选择?

Question

例如，包含选项 A 和选项 B 的第一个组合框。 如果我在第一个组合框中选择选项 A，则第二个组合框包含选项 1,2,3,4,5。 第二个组合框包含选项 a，b，c，d，e，如果我在第一个组合框中选择选项 B。

如何在 PyQt5 中执行此操作？我已经搜索了Qcombobox类，有2个类activated和currentIndexChanged，但不知道我需要使用哪一个以及如何在PyQt5中使用它。

Answer 1

这就是我会这样做的：

import sys
from PyQt5 import QtWidgets

class ComboWidget(QtWidgets.QWidget):
def __init__(self, parent=None):
super(ComboWidget, self).__init__(parent)
self.setGeometry(50, 50, 200, 200)
layout = QtWidgets.QVBoxLayout(self)
self.comboA = QtWidgets.QComboBox()
# The second addItem parameter is itemData, which we will retrieve later
self.comboA.addItem('A', ['1', '2', '3', '4'])
self.comboA.addItem('B', ['a', 'b', 'c', 'd', 'e'])
self.comboA.currentIndexChanged.connect(self.indexChanged)
layout.addWidget(self.comboA)
self.comboB = QtWidgets.QComboBox()
# We could have added the 1,2,3,4 items directly, but the following
# is a bit more generic in case the combobox starts with a different
# index for some reason:
self.indexChanged(self.comboA.currentIndex())
layout.addWidget(self.comboB)
self.show()
def indexChanged(self, index):
self.comboB.clear()
data = self.comboA.itemData(index)
if data is not None:
self.comboB.addItems(data)

def main():
app = QtWidgets.QApplication(sys.argv)
w = ComboWidget()
sys.exit(app.exec_())
if __name__ == '__main__':
main()

这样，您的代码就更加面向未来，因为如果您想在某个时候这样做，它可以让您非常轻松地添加/修改/删除任何下拉列表中的项目。

Answer 2

我通过使用 3 个组合框(让我们称它们为 x、y 和 z(让它工作

1. x 包含 A、B，用于选择其他组合框上显示的选项。选择 A 显示组合框 y，选择 B 显示组合框 z

2. y 包含 1,2,3,4

3. Z 包含 a，b，c，d

我使用QStackedLayout代替第二个组合框，加载了两个组合框(y 和 z(，并根据组合框 x 中选择的选项一次显示其中一个。

方法comboOptionChanged处理此问题。 每当在组合框 x 中选择不同的选项时，都会调用此方法。

import sys
from PyQt5.QtWidgets import QWidget, QComboBox, QApplication, QFormLayout, QLabel,QStackedLayout
class DynamicComboExample(QWidget):
def __init__(self):
super().__init__()
self.setupUI()
def setupUI(self):
self.setGeometry(300,300, 500, 300)
self.show()
combo_a = QComboBox(self)
combo_a.addItem('A')
combo_a.addItem('B')
# set slot for when option of combobox A is changed
combo_a.currentIndexChanged[int].connect(self.comboOptionChanged)
self.combo_b = QComboBox()
self.combo_b.addItem('1')
self.combo_b.addItem('2')
self.combo_b.addItem('3')
self.combo_b.addItem('4')
self.combo_c = QComboBox()
self.combo_c.addItem('a')
self.combo_c.addItem('b')
self.combo_c.addItem('c')
self.combo_c.addItem('d')
self.combo_c.addItem('e')
# use a stacked layout to view only one of two combo box at a time
self.combo_container_layout = QStackedLayout()
self.combo_container_layout.addWidget(self.combo_b)
self.combo_container_layout.addWidget(self.combo_c)
combo_container = QWidget()
combo_container.setLayout(self.combo_container_layout)
form_layout = QFormLayout()
form_layout.addRow(QLabel('A:t'), combo_a)
# the stacked layout is placed in place of the (meant to be) second combobox
form_layout.addRow(QLabel('B:t'), combo_container)

self.setLayout(form_layout)

def comboOptionChanged(self, idx):
''' gets called when option for combobox A is changed'''
# check which combobox_a option is selected ad show the appropriate combobox in stacked layout
self.combo_container_layout.setCurrentIndex(0 if idx == 0 else 1)

def main():
app= QApplication(sys.argv)
w = DynamicComboExample()
exit(app.exec_())
if __name__ == '__main__':
main()