python - PyQt5 ComboBox 虚拟占位符

Question

我碰巧使用了 qcombobox，但找不到添加虚拟占位符的方法（就像我们在 tkinter 中一样）。例如，我想要的组合框是这样的：

- 选一个 -

苹果

香蕉

猕猴桃

我已经有了元素；Apple、Banana、Kiwi 就位，但我希望--Choose One--在我单击它时消失。

**Tkinter version**

from tkinter import ttk
#---
#some code here
#---
lst = ['Apple','Banana','Kiwi']

self.w0 = ttk.Combobox(self, values = lst, state='readonly')
self.w0.set('--Choose One--') ### This is the functionality that I need
self.w0.pack()

**PyQt version**
from PyQt5 import QtWidgets
lst = ['Apple','Banana','Kiwi']
#---
#some code here
#---
self.comboBox = QtWidgets.QComboBox()
self.comboBox.addItems(lst)
self.layout.addWidget(self.comboBox) ## self.layout is defined but not shown here

### I might add it as an item of the comboBox like
### self.comboBox.addItem('--Choose One--') but it then becomes selectable 
### which I don't want it to.

标签： pythonpyqt5qcombobox

Answer 1

（在示例中）的set()方法等价于的属性：ttk.ComboboxplaceholderTextQComboBox

self.comboBox.setPlaceholderText("--Choose One--")