如何在不使用按钮信号的情况下使用QCombobox更新Qlabel

Question

我想知道如何从组合框中自动添加或更新qlabel。当我更改QComboBox中的选项时，QLabel应该会更新。

False

Answer 1

  

void QComboBox :: currentIndexChanged（const QString＆text）

     

无论何时通过用户交互或以编程方式更改组合框中的currentIndex，都会发送此信号。该项目的文本已通过。

from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
from PyQt5.QtGui import *


convert_options = ["Celcius to Farenheit", 
                   "Celcius to Kelvin", 
                   "Farenheit to Celcius", 
                   "Farenheit to Kelvin", 
                   "Kelvin to Celcius", 
                   "Kelvin to Farenheit"]   

class Frame(QWidget):
    def __init__(self, convert_options ):
        super().__init__()
#        uic.loadUi("temperature_converter.ui", self)

        self.convert_options = convert_options
        self.initUI()

    def initUI(self):

        self.label_unit = QLabel()

        self.comboBox_choices = QComboBox()
        self.comboBox_choices.currentIndexChanged[str].connect(self.unit_choice)
        self.comboBox_choices.addItems(self.convert_options)
        # comboText = self.comboBox_choices.currentText()
        # self.unit_choice(comboText)
#        self.button_choices()
# This if statement if used needs a button signal  

        self.grid = QGridLayout() 
        self.grid.addWidget(self.label_unit, 0, 0)
        self.grid.addWidget(self.comboBox_choices, 1, 0)

        self.setLayout(self.grid)

    def unit_choice(self, comboText):
        if comboText == "Celcius to Farenheit":
            self.label_unit.setText("Celcius to Farenheit: {}".format(chr(176) + "C"))
        elif comboText == "Celcius to Kelvin":
            self.label_unit.setText("Celcius to Kelvin: {}".format(chr(176) + "C"))
        elif comboText == "Farenheit to Celcius":
            self.label_unit.setText("Farenheit to Celcius: {}".format(chr(176) + "F"))
        elif comboText == "Farenheit to Kelvin":
            self.label_unit.setText("Farenheit to Kelvin: {}".format(chr(176) + "F"))
        elif comboText == "Kelvin to Celcius":
            self.label_unit.setText("Kelvin to Celcius: {}".format(chr(176) + "K"))
        elif comboText == "Kelvin to Farenheit":
            self.label_unit.setText("Kelvin to Farenheit: {}".format(chr(176) + "K"))


if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    w = Frame(convert_options)
    w.setWindowTitle(' update a qlabel from the combobox automatically')
    w.setWindowIcon(QIcon('im.png'))
    w.show()
    sys.exit(app.exec())