如何在屏幕上居中放置QMessageBox和QInputDialog？

Question

我有此功能可将对象居中放在屏幕中间。

我想居中QMainWindow，QInputDialog和QMessageBox。

这是我的MessageBox：

def _Warning(self,_type):
        infoBox = QtWidgets.QMessageBox()
        infoBox.setIcon(QtWidgets.QMessageBox.Warning)
        infoBox.setWindowTitle("Warning")
        if (_type=="File"):
            infoBox.setText("The File Already exist in the current Directory")
        else:
            infoBox.setText("The Folder Already exist in the current Directory")

        self.center(infoBox)

        infoBox.exec_()

这是我的QInputDialog：

def AddFile_B(self):
        self.cuadro = QInputDialog()
        self.center(self.cuadro)
        text, okPressed = self.cuadro.getText(self, "New File","File Name:", QLineEdit.Normal, "")
        if okPressed and text != '':
            file = File_Node(text)
            verify = self.bonsai_B.addChild(file)
            if (verify == True):
                item = QtWidgets.QListWidgetItem(None,0)
                self.TreeB.addItem(item)
            else:
                del file
                self._Warning("File")

这是我的中心功能：

def center(self,object):
    qtRectangle = object.frameGeometry() 
    centerPoint = QtWidgets.QDesktopWidget().availableGeometry().center()
    qtRectangle.moveCenter(centerPoint)
    object.move(qtRectangle.topLeft())

我只能居中QMainWindow。

逻辑是将对象移动到topLeft点（screenWidth / 2-objectWidth / 2，screenHeight /
2-objectHeight / 2），但是我不知道自己在做什么。

Answer 1

在QMessageBox此方法中调整尺寸的情况下exec_()，因此可能的解决方案是QTimer.singleShot()在显示后的瞬间使用几何形状进行更改。

from functools import partial
from PyQt5 import QtCore, QtWidgets


def center(window):
    # https://wiki.qt.io/How_to_Center_a_Window_on_the_Screen

    window.setGeometry(
        QtWidgets.QStyle.alignedRect(
            QtCore.Qt.LeftToRight,
            QtCore.Qt.AlignCenter,
            window.size(),
            QtWidgets.qApp.desktop().availableGeometry(),
        )
    )


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

        self.btn_warning = QtWidgets.QPushButton(
            "Open QMessageBox", clicked=self.open_qmessagebox
        )

        lay = QtWidgets.QVBoxLayout(self)
        lay.addWidget(self.btn_warning)

        center(self)

    @QtCore.pyqtSlot()
    def open_qmessagebox(self):
        infoBox = QtWidgets.QMessageBox()
        infoBox.setIcon(QtWidgets.QMessageBox.Warning)
        infoBox.setWindowTitle("Warning")
        infoBox.setText("The XXX Already exist in the current Directory")
        wrapper = partial(center, infoBox)
        QtCore.QTimer.singleShot(0, wrapper)
        infoBox.exec_()


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)
    w = Widget()
    w.show()
    sys.exit(app.exec_())

-QInputDialog

对于QInputDialog，QInputDialog :: getText（）方法是静态的，因此“
self.cuadro”对象不是窗口，因为该窗口是在该方法中创建的。如果将父级传递给getText（），则默认情况下它将相对于此居中。

因此，如果QMainWindow居中并假定QMainWindow是自身，则无需修改任何内容。

相反，如果父母不在屏幕上居中，则有两种可能的解决方案：

• 不要使用静态方法并通过QInputDialog实例实现逻辑：

  from functools import partial
  from PyQt5 import QtCore, QtWidgets
  

  def center(window):
  # https://wiki.qt.io/How_to_Center_a_Window_on_the_Screen

  window.setGeometry(
      QtWidgets.QStyle.alignedRect(
          QtCore.Qt.LeftToRight,
          QtCore.Qt.AlignCenter,
          window.size(),
          QtWidgets.qApp.desktop().availableGeometry(),
      )
  )
  

  class Widget(QtWidgets.QWidget):
  def init(self, parent=None):
  super().init(parent)

      self.btn_inputdialog = QtWidgets.QPushButton(
          "Open QInputDialog", clicked=self.open_qinputdialog
      )
  
      lay = QtWidgets.QVBoxLayout(self)
      lay.addWidget(self.btn_inputdialog)
  
      center(self)
  
  @QtCore.pyqtSlot()
  def open_qinputdialog(self):
      dialog = QtWidgets.QInputDialog(self)
      dialog.setWindowTitle("New File")
      dialog.setLabelText("File Name:")
      dialog.setTextEchoMode(QtWidgets.QLineEdit.Normal)
      dialog.setTextValue("")
      wrapper = partial(center, dialog)
      QtCore.QTimer.singleShot(0, wrapper)
      text, okPressed = (
          dialog.textValue(),
          dialog.exec_() == QtWidgets.QDialog.Accepted,
      )
      if okPressed and text:
          print(text)
  

  if name == “main”:
  import sys

  app = QtWidgets.QApplication(sys.argv)
  w = Widget()
  w.show()
  sys.exit(app.exec_())
  

• 继续使用静态方法，并使用findChildren（）获取窗口

  from functools import partial
  from PyQt5 import QtCore, QtWidgets

  def center(window):
  # https://wiki.qt.io/How_to_Center_a_Window_on_the_Screen

  window.setGeometry(
      QtWidgets.QStyle.alignedRect(
          QtCore.Qt.LeftToRight,
          QtCore.Qt.AlignCenter,
          window.size(),
          QtWidgets.qApp.desktop().availableGeometry(),
      )
  )
  

  class Widget(QtWidgets.QWidget):
  def init(self, parent=None):
  super().init(parent)

      self.btn_inputdialog = QtWidgets.QPushButton(
          "Open QInputDialog", clicked=self.open_qinputdialog
      )
  
      lay = QtWidgets.QVBoxLayout(self)
      lay.addWidget(self.btn_inputdialog)
  
      center(self)
  
  @QtCore.pyqtSlot()
  def open_qinputdialog(self):
      parent = self
      dialogs = parent.findChildren(QtWidgets.QInputDialog)
  
      def onTimeout():
          dialog, *_ = set(parent.findChildren(QtWidgets.QInputDialog)) - set(dialogs)
          center(dialog)
  
      QtCore.QTimer.singleShot(0, onTimeout)
      text, okPressed = QtWidgets.QInputDialog.getText(
          parent, "New File", "File Name:", QtWidgets.QLineEdit.Normal, ""
      )
      if okPressed and text:
          print(text)
  

  if name == “main”:
  import sys

  app = QtWidgets.QApplication(sys.argv)
  w = Widget()
  w.show()
  sys.exit(app.exec_())