QLayout: Attempting to add QLayout "" to MainWindow "", which already has a layout

Hi,
I'm new and probably this is a dumb question.
I've got the error that you can see as subject. Actually, it seems a warning since the code provide a output that I like (many improvings are needed here), but I would like to give ride to these warning.

The answers provided in internet does not help me too much, so I asked to this forum.

The code that I have written is after my signature.
Thanks,
M

Code:

---

from PyQt5.QtCore import Qt, QSize
from PyQt5.QtWidgets import (QWidget, QHBoxLayout, QVBoxLayout, 
    QLabel, QApplication, QPushButton, QLineEdit)
from PyQt5 import QtGui
from PyQt5.QtGui import QPixmap, QIcon, QFont
 
import sys
 
class MainWindow(QWidget):
    def __init__(self):
        super().__init__()
 
        self.initUI()
 
    def initUI(self):
 
        hbox = QHBoxLayout(self)
        hbox.setSpacing(10)
 
        vBoxMain = QVBoxLayout(self) #Vertical box
        vBoxMain.setSpacing(35)    #space between widgets
 
        vBoxContext = QVBoxLayout(self) #Vertical box
        vBoxContext.setSpacing(35)    #space between widgets
 
        self.loadMainMenu(vBoxMain)
        self.loadContextMenu(vBoxContext)
 
        hbox.addLayout(vBoxMain)
        hbox.addLayout(vBoxContext)
 
        #self.setLayout(hbox)
        #self.move(300,200)
        self.setWindowTitle('AnForA')
        self.setWindowIcon(QIcon('upoSmallLogo.png'))
 
        self.show()
 
    def loadContextMenu(self, vBox):
 
        vbox = QVBoxLayout(self) 
        vbox.setSpacing(10)
 
 
        hbox = QHBoxLayout(self)
        hbox.setSpacing(10)
 
        #Add edit text
        insertFile = QLineEdit(self)
        insertFile.setText("Select apk file here")
        hbox.addWidget(insertFile)
 
        #Add browse button
        browsebtn = QPushButton('Browse', self)
        browsebtn.clicked.connect(QApplication.instance().quit)
        #apkbtn.resize(apkbtn.sizeHint())
        hbox.addWidget(browsebtn)
        #apkbtn.move(250, 250) 
 
        vBox.addLayout(hbox)
 
    def loadMainMenu(self, vBox):
        #Add logo UPO image
        pixmap = QPixmap("logoUPO.png")
        labelImg = QLabel(self)
        pixmap2 = pixmap.scaledToWidth(300)
        labelImg.setPixmap(pixmap2)
        labelImg.setAlignment(Qt.AlignCenter)
        vBox.addWidget(labelImg)
 
        labelDesc = QLabel(self)
        labelDesc.setText('AnForA\nAndroid Forensic Automator')
        labelDesc.setAlignment(Qt.AlignCenter)
        labelDesc.setFont(QtGui.QFont("Times", 12, QtGui.QFont.Bold))
        vBox.addWidget(labelDesc)
 
        #Add Install APK button
        apkbtn = QPushButton('Install APK into Android Device', self)
        apkbtn.clicked.connect(QApplication.instance().quit)
        #apkbtn.resize(apkbtn.sizeHint())
        vBox.addWidget(apkbtn)
        #apkbtn.move(250, 250) 
 
        #Add Install APK button
        rcdbtn = QPushButton('Record user session', self)
        rcdbtn.clicked.connect(QApplication.instance().quit)
        #apkbtn.resize(apkbtn.sizeHint())
        vBox.addWidget(rcdbtn)
        #apkbtn.move(250, 250) 
 
        #Add Install APK button
        forbtn = QPushButton('Start forensic analysis', self)
        forbtn.clicked.connect(QApplication.instance().quit)
        #apkbtn.resize(apkbtn.sizeHint())
        vBox.addWidget(forbtn)
        #apkbtn.move(250, 250) 
 
 
        #Add quit button
        qbtn = QPushButton('Quit', self)
        qbtn.clicked.connect(QApplication.instance().quit)
        #qbtn.resize(qbtn.sizeHint())
        #qbtn.move(250, 300) 
        vBox.addWidget(qbtn)
 
        """
        #Add Label main menu
        labelMainMenu = QtGui.QLabel('AnForA\nAndroid Forensic Automator',cWidget)
        labelMainMenu.setFont(QtGui.QFont("Times", 16, QtGui.QFont.Bold))
        labelMainMenu.setFixedWidth(400)
        vBox.addWidget(labelMainMenu)
 
        cWidget.setLayout(vBox)
        self.setCentralWidget(cWidget)
        """
 
if __name__ == '__main__':
    app = QApplication(sys.argv)
    main = MainWindow()
    sys.exit(app.exec_())

---

QMainWindow already has a layout, i.e. for placing toolbars, statusbar and menubar correctly around the "center widget".

You are creating a QHBoxLayout and passing "self" to its constructor, which means you are trying to set this layout as the main window's layout instead.

Instead of

Code:

---

hbox = QHBoxLayout(self)
hbox.setSpacing(10)

---

you do this

Code:

---

widget = QWidget(self)
self.setCentralWidget(widget)
 
hbox = QHBoxLayout(widget)
hbox.setSpacing(10)

---

Cheers,
_

Thanks for your prompt reply.
The suggestion you provide me rises up a error:

Code:

---

Traceback (most recent call last):
  File "anforaGui.py", line 133, in <module>
    main = MainWindow()
  File "anforaGui.py", line 24, in __init__
    self.initUI()
  File "anforaGui.py", line 29, in initUI
    self.setCentralWidget(widget)
AttributeError: 'MainWindow' object has no attribute 'setCentralWidget'

---

I have a couple of questions:
- where should I note that I'm using QMainWindow (I did not find it in the code, I know, dumb question)
- which is the best website to start using qt? This concept of central widget is not defined in many guide that I read

Thanks,
Massimo

Yes, sorry, my bad.

For some reason I thought that your MainWindow as derived from QMainWindow.

So the problem is really the two QVBoxLayout constructions (vBoxMain and vBoxContext).
Simply create these two without passing "self" to the constructor.

Cheers,
_

Quote:

---

Originally Posted by anda_skoa

Yes, sorry, my bad.

For some reason I thought that your MainWindow as derived from QMainWindow.

So the problem is really the two QVBoxLayout constructions (vBoxMain and vBoxContext).
Simply create these two without passing "self" to the constructor.

Cheers,
_

---

Thanks, I removed it and now I get just one warning. I think it is related to the first hbox:

Code:

---

hbox = QHBoxLayout(self)
hbox.setSpacing(10)

---

but if I remove the "self" here, I get all widgets overlapped in a microscopic window.

Thanks again,
M

One layout needs to be responsible for the widget "self".

There are two ways to do that
1) passing "self" to that layout's constructor
2) calling self.setLayout() with that layout as an argument.

Cheers,
_