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

Question

例如，带有选项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。 如果我在第一个组合框中选择选项B，第二个组合框包含选项a，b，c，d，e。

我怎么能在PyQt5中做到这一点？我搜索了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

这是我会怎么做：

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() 

这样一来，你的代码是多一点面向未来的，因为这将允许您添加/修改/删除任何项目如果你想在某些时候这么做，很容易。

Answer 2

我把它用3个组合框的工作（可以称它们的x，y和z）

1. x包含A，B和用于选择哪些选项出现在其他组合框。选择一个显示的组合框y和选择B表示组合框ž

2. y保存1,2,3,4

3. Z含有A，B，C，d

我使用的QStackedLayout在第二个组合框的位置，加载了两个组合框（y和z），并根据在组合框x中选择哪个选项一次显示其中的一个。

方法comboOptionChanged处理这个。 只要选择组合框x中的不同选项，就会调用此方法。

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()