PyQt4 QMessageBox文本更改

Question

I am using this simple code to show warning boxes:

w = QWidget() 
result = QMessageBox.warning(w, 'a', x, QMessageBox.Ok)

Is there any way to change MESSAGE dynamically? I want to make a popup which will inform user abut progress of a task that is running in background.

Edit:

Well I tried to do so making this script for testing:

def handleButton(self):
        self.msgBox = QMessageBox(self)
        self.msgBox.setWindowTitle("Title")
        self.msgBox.setIcon(QMessageBox.Warning)
        self.msgBox.setText("Start")
        self.msgBox.show()
        x = 0
        for x in range (100):
            x = x + 1
            print (x)
            self.msgBox.setText(str(x))
            self.msgBox.show()
            time.sleep(1)

The text only shows after finishing the 'for loop', why?

Answer 1

Instead of using a static method you could create an object of the class.

import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *

class Widget(QWidget):
    def __init__(self, parent=None):
        QWidget.__init__(self, parent)

        self.msgBox = QMessageBox(self)
        self.msgBox.setWindowTitle("Title")
        self.msgBox.setIcon(QMessageBox.Warning)
        self.msgBox.setText("Start")
        self.msgBox.show()

        timer = QTimer(self)
        timer.timeout.connect(self.onTimeout)
        timer.start(1000)

    def onTimeout(self):
        self.msgBox.setText("datetime: {}".format(QDateTime.currentDateTime().toString()))


if __name__ == '__main__':
    app = QApplication(sys.argv)
    w = Widget()
    w.show()
    sys.exit(app.exec_())

---

Update:

The problem in your example is the use of time.sleep() . Qt is executed in an eventloop, this eventloop allows you to handle the events of the mouse, keyboard, redraw, etc. but the time.sleep() blocks the eventloop, this you can check trying to change the size of the window, you will see that you can not do it.

Assuming you use time.sleep() to pause, then you must use QEventLoop with QTimer that does not block the Qt eventloop.

def handleButton(self):
    self.msgBox = QMessageBox(self)
    self.msgBox.setWindowTitle("Title")
    self.msgBox.setIcon(QMessageBox.Warning)
    self.msgBox.setText("Start")
    self.msgBox.show()

    for x in range(100):
        self.msgBox.setText(str(x+1))
        loop = QEventLoop()
        QTimer.singleShot(1000, loop.quit)
        loop.exec_()