python - 参数 1 具有意外类型 'NoneType'？

Question

我的 PyQt 按钮操作有问题。我想用函数发送一个字符串，但我收到了这个错误:

TypeError: argument 1 has unexpected type 'NoneType'

import sys

from PyQt5.QtWidgets import QApplication, QPushButton, QAction
from PyQt5.QtCore import QObject, pyqtSignal
from PyQt5.QtGui import *
from PyQt5.uic import *

app = QApplication(sys.argv)
cocktail = loadUi('create.ui')

def mixCocktail(str):
      cocktail.show()
      cocktail.showFullScreen()
      cocktail.lbl_header.setText(str)


widget = loadUi('drinkmixer.ui')

widget.btn_ckt1.clicked.connect(mixCocktail("string"))

widget.show()
sys.exit(app.exec_())

Answer 1

根据 user3030010 的建议和 ekhumoro它需要一个可调用的函数。在这种情况下，您应该将该参数替换为 lambda: mixCocktail("string")还有不要使用str 它是python 内置数据类型我已将其替换为_str

import sys

from PyQt5.QtWidgets import QApplication, QPushButton, QAction
from PyQt5.QtCore import QObject, pyqtSignal
from PyQt5.QtGui import *
from PyQt5.uic import *

app = QApplication(sys.argv)
cocktail = loadUi('create.ui')

def mixCocktail(_str):
      cocktail.show()
      cocktail.showFullScreen()
      cocktail.lbl_header.setText(_str)
      

widget = loadUi('drinkmixer.ui')

widget.btn_ckt1.clicked.connect(lambda: mixCocktail("string"))

widget.show()
sys.exit(app.exec_())

关于 lambda 函数的更多信息:What is a lambda (function)?