如何在 GUI 中只运行一次函数

Question

I want to run the function removeHi(self) only once in my program, how to accomplish this. Please advise me. My entire code below:

import sys
from PyQt5.QtWidgets import *
from functools import wraps

class TestWidget(QWidget):
gee = ''
def __init__(self):
    global gee
    gee = 'Hi'
    QWidget.__init__(self, windowTitle="A Simple Example for PyQt.")
    self.outputArea=QTextBrowser(self)
    self.outputArea.append(gee)
    self.helloButton=QPushButton("reply", self)
    self.setLayout(QVBoxLayout())
    self.layout().addWidget(self.outputArea)
    self.layout().addWidget(self.helloButton)
    self.helloButton.clicked.connect(self.removeHi)
    self.helloButton.clicked.connect(self.sayHello)

def removeHi(self):
    self.outputArea.clear()


def sayHello(self):
    yourName, okay=QInputDialog.getText(self, "whats your name?", "name")
    if not okay or yourName=="":
        self.outputArea.append("hi stranger！")
    else:
        self.outputArea.append(f"hi，{yourName}")

app=QApplication(sys.argv)
testWidget=TestWidget()
testWidget.show()
sys.exit(app.exec_())

The GUI will show "Hi" when the program runs. I want the "Hi" in QTextBrowser removed after I push the button reply , but the program will clear everything in the text browser whenever I clicked the button.

My goal is: only the first Hi be removed, and the name from function sayHello(self) will remain whenever I push the reply button.

Answer 1

The problem resides in the logic of your program: you should check whether the text must be cleared or not, using a default value that would be changed whenever the dialog changes the output:

class TestWidget(QWidget):
    clearHi = True
    def __init__(self):
        QWidget.__init__(self, windowTitle="A Simple Example for PyQt.")
        self.outputArea = QTextBrowser()
        self.outputArea.append('Hi')
        self.helloButton = QPushButton("reply")
        layout = QVBoxLayout(self)
        layout.addWidget(self.outputArea)
        layout.addWidget(self.helloButton)
        self.helloButton.clicked.connect(self.removeHi)
        self.helloButton.clicked.connect(self.sayHello)

    def removeHi(self):
        if self.clearHi:
            self.outputArea.clear()

    def sayHello(self):
        yourName, okay = QInputDialog.getText(
            self, "whats your name?", "name")
        if not okay:
            return
        self.clearHi = False
        if not yourName:
            self.outputArea.append("hi stranger!")
        else:
            self.outputArea.append(f"hi, {yourName}")

Note: do not use globals.