PyQt5:启动后,QMessageBox消失了 [英] PyQt5: QMessageBox vanishes after starting
问题描述
当我调用错误消息一(见代码注释)时,该消息迅速出现然后消失.但是,如果我调用错误消息二,则它会出现,并且仅在单击确定"按钮时消失.
When I invoke Error Message One (see comments in code) the message quickly appears and then vanishes. But if I invoke Error Message Two, it appears and only vanishes when I click on the 'OK' button.
如何解决它,以使错误消息一像错误消息二一样起作用?
How can I fix it so that Error Message One works like Error Message Two?
try:
connection = pymysql.connect(host = 'localhost',
user = 'root',
db = 'Telephon Register',
cursorclass = pymysql.cursors.DictCursor)
cur = connection.cursor()
if number!= "":
cur.execute("SELECT Number FROM formen WHERE Telephonebook = " + self.number.text() )
result = cur.fetchone()
if len(result) == 0:
cur.execute("INSERT INTO formen VALUES(" + self.number.text())
connection.commit()
else:
print("The number " + number+ " already exists.")
else:
print("You have not typed a number!")
msg = QMessageBox() #EXCEPTION MESSAGE ONE
msg.setIcon(2)
msg.setText("Some Text")
msg.setInformativeText("Some informative text")
msg.setWindowTitle("Error")
msg.show()
connection.close()
except:
print("Connection does not work!")
msg = QMessageBox() # EXCEPTION MESSAGE TWO
msg.setIcon(3)
msg.setText("Some Text")
msg.setInformativeText("Some message")
msg.setWindowTitle("Error")
msg.show()
推荐答案
消息框消失了,因为您没有保留对它的引用,因此该函数返回后将立即对其进行垃圾回收.
The message-box disappears because you're not keeping a reference to it, so it gets garbage-collected as soon as the function returns.
要在您的示例中解决此问题,请使用exec
打开消息框,以使它们一直阻塞,直到用户关闭它们为止:
To fix this in your example, open the message-boxes using exec
, so that they block until the user closes them:
msg = QMessageBox()
...
msg.exec_()
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