python qt : automatically resizing main window to fit content

Question

I have a main window which contains a main widget, to which a vertical layout is set. To the layout is added a QTableWidget only (for the moment).

When I start the application and call show on the main_window, only part of the QTableWidget is shown. I can extend the window manually to see it all, but I would like the window to have its size nicely adapted to the size of the QTableWidget.

Googling the question found a lot of posts on how to use resize to an arbitrary size, and call to resize(int) works fine, but this is not quite what I am asking

Lots of other posts are not explicit enough, e.g "use sizePolicy" or "use frameGeometry" or "use geometry" or "use sizeHint". I am sure all of them may be right, but an example on how to would be awesome.

I'm willing to bet that there's something wrong in the way you set up your layouts/widgets. In a properly layouted scenario, your main window would never shrink smaller than the enclosed tablewidgets minimum-size. You'll need to provide some code example. — ThorngardSO, Jan 07 '16 at 12:46

Daniele Pantaleone · Answer 1 · 2016-01-07T10:54:18.647

5

You can do something like this, from within your MainWindow after placing all the elements you need in the layout:

self.setFixedSize(self.layout.sizeHint())

This will set the size of the MainWindow to the size of the layout, which is calculated using the size of widgets that are arranged in the layout.

edited Jan 07 '16 at 10:54

answered Jan 06 '16 at 18:42

Daniele Pantaleone

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Hi, does not seem to work ... I tried sizeHint on different object, and what it returns does not seem to match anything --; – Vince Jan 07 '16 at 11:09
`AttributeError: 'builtin_function_or_method' object has no attribute 'sizeHint'`, though it worked using the central widget. The big issue here is the window becomes fixed in size, and using table.sizeHint made it too small. – rtaft Feb 24 '23 at 14:59
doesn't work... – Stéphane Aug 14 '23 at 13:14

score 2 · Answer 2 · answered Dec 06 '16 at 05:16

I think overriding sizeHint() on the QTableWidget is the key:

import sys
from PyQt5.QtCore import QSize
from PyQt5.QtWidgets import QApplication, QMainWindow, QTableWidget

class Table(QTableWidget):
  def sizeHint(self):
    horizontal = self.horizontalHeader()
    vertical = self.verticalHeader()
    frame = self.frameWidth() * 2
    return QSize(horizontal.length() + vertical.width() + frame,
                 vertical.length() + horizontal.height() + frame)

class Main(QMainWindow):
  def __init__(self, parent=None):
    super(Main, self).__init__(parent)
    top = Table(3, 5, self)
    self.setCentralWidget(top)

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

It might be a good idea to use `vertical.sizeHint().width()` instead of `vertical.width()` and `horizontal.sizeHint().height()` instead of `horizontal.height()`. See https://stackoverflow.com/a/69035062/2705757 . — AXO, Sep 02 '21 at 18:32

score 0 · Answer 3 · edited Oct 11 '18 at 00:26

You can use sizeHint() but not as stated in the other answers. sizeHint() returns a QSize object with a width and height. Let's say you have a main window mainWindow and a widget inside it called content. If your resizing involves content height to get bigger, you can fit the mainWindow to it like this:

mainWindow.resize(mainWindow.sizeHint().width,
        mainWindow.size().height() + content.sizeHint().height());

score 0 · Answer 4 · answered Sep 10 '20 at 14:55

Old but i experienced this a while back and seeing how the answers here didn't exactly work for me.

Here's what i did:

Please make sure you have the central widget for the 'mainwindow' set properly and the parent of the layout is the central widget, Then set a sizepolicy for the mainwindow/widget as you wish.


from PyQt5 import QtCore, QtGui, QtWidgets
import sys

class RandomWidget(QtWidgets.QWidget):

    def __init__(self, parent=None):
        super(RandomWidget, self).__init__(parent)
        self.layout = QtWidgets.QVBoxLayout()
        self.setLayout(self.layout)
        self.ui()
        self.layout.addWidget(self.table)
        self.layout.addWidget(self.table2)

    def ui(self):
        self.table = QtWidgets.QTableWidget()
        self.table.setMinimumSize(800,200)
        self.table2 = QtWidgets.QTableWidget()

class Mainwindow(QtWidgets.QMainWindow):

    def __init__(self):
        self.widget = None
        super(Mainwindow, self).__init__()
        self.setWindowTitle('test')

    def ui(self):
        self.setCentralWidget(self.widget)
        self.show()
    

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    Window = Mainwindow()
    Window.widget = RandomWidget(Window)
    Window.ui()
    sys.exit(app.exec_())

Thank - but I don't see "set a sizepolicy" anywhere in the code example? Only setMinimumSize? — sdbbs, Jan 27 '21 at 09:38

score 0 · Answer 5 · answered Mar 22 '23 at 05:21

When you create a main class, set the width of height of some widget to change according to the main window.

def _setupUi(self):
    self.original_width = 1280
    self.original_height = 773
    self.file_list_w = 256
    self.file_list_h = 350
    self.file_list.setGeometry(QRect(30, 20, self.file_list_w, self.file_list_h))

and in the main class, add this

def resizeEvent(self, event):
    width = self.frameGeometry().width()
    height = self.frameGeometry().height()
    w_proportion = width / self.original_width
    h_proportion = height / self.original_height
    self.file_list.resize(int(self.file_list_w*w_proportion), int(self.file_list_h*h_proportion))

And do the same thing for any widget needs to be adjusted when the main windows is resizing.

python qt : automatically resizing main window to fit content

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