Shrink a QPushButton width to the minimum

Question

This seems like such a simple thing, but I can't seem to figure it out. How do I make the button the minimum width. It keeps expanding to the width of the layout I put it in. In the following example, the QPushButton width ends up the same as the QLabel:

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

class MyWindow(QWidget):

    def __init__(self,parent = None):

        QWidget.__init__(self,parent)

        layout = QVBoxLayout()
        layout.addWidget(QLabel('this is a really, really long label that goes on and on'))
        layout.addWidget(QPushButton('short button'))

        self.setLayout(layout)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MyWindow()
    window.show()
    sys.exit(app.exec_())

Solution 1

setMaximumWidth works for me

from PyQt4 import QtGui

class Window(QtGui.QWidget):
    def __init__(self):
        super(Window, self).__init__()
        layout = QtGui.QHBoxLayout()
        texts = [":)",
                 "&Short",
                 "&Longer",
                 "&Different && text",
                 "More && text",
                 "Even longer button text", ]
        for text in texts:
            btn = QtGui.QPushButton(text)
            double = text.count('&&')
            text = text.replace('&', '') + ('&' * double)
            width = btn.fontMetrics().boundingRect(text).width() + 7
            btn.setMaximumWidth(width)
            layout.addWidget(btn)
        self.setLayout(layout)

if __name__ == '__main__':
    import sys

    app = QtGui.QApplication(sys.argv)
    mainWin = Window()
    mainWin.show()
    sys.exit(app.exec_())

Solution 2

See http://qt-project.org/doc/qt-4.8/qwidget.html#sizePolicy-prop and http://qt-project.org/doc/qt-4.8/qsizepolicy.html#Policy-enum to learn on how to control widget sizing in a dynamic layout.

If you don't get satisfactory results by changing the SizePolicy alone (you should), you could also look into these nice guys: http://qt-project.org/doc/qt-4.8/qspaceritem.html

Comments

[chacham15]

IIRC QPushButton has a fixed minimum width (of 80 i think), trying to force it to be smaller with a policy will cause unpredictable results since that means that the policy will ignore the minimum width.

[ypnos]

In my application I have a QPushButton with both minimum and maximum width set to 16, displaying an icon of width 8. It works as intended. However, in OS X the button has not the same OS X Aqua style as all other buttons but seems to be reverted to a plain button to fulfill its size properties. So this is a side effect that needs to be considered.

[Mad Physicist]

This is a very nice demo. By the way, you can transform text without any intermediate steps by just doing width = btn.fontMetrics().boundingRect(re.sub('&(?=(?:&&)*[^&])', '', text)).width() + 7. You can just replace all & that are followed by an even number of &.

[Mad Physicist]

This has the advantage that the & get processed properly in-place instead of being added back to the end of the string.