Qt formlayout not expanding qplaintextedit vertically

Question

I'm confused why a QPlainTextEdit widget will not resize vertically when added to a QFormLayout. In the code below the text field correctly scales up horizontally, but does not scale up vertically.

Can anyone explain this behavior and offer a solution? I've tried all the tricks I know to no avail.

from PyQt4 import QtGui

class Diag(QtGui.QDialog):

    def __init__(self, parent, *args, **kwargs):
        QtGui.QDialog.__init__(self, parent)
        layout = QtGui.QFormLayout(self)
        widg = QtGui.QPlainTextEdit(self)
        layout.addRow('Entry', widg)

if __name__ == '__main__': #pragma: no cover
    app = QtGui.QApplication([])
    window = Diag(None)
    window.show()
    app.exec_()

Here is an example of the QPlainTextEdit widget not resizing vertically:

This is on Windows 7 using PyQt 4.5.2 and Python 32-bit 2.6.

Thanks.

Hifi

I get the exact opposite behaviour on both Linux and WinXP. The text-edit resizes vertically to fill the space no matter what settings are chosen (e.g. setFieldGrowthPolicy(), expandingDirections(), etc) – Velasquez

Huh, which Qt version are you using ekhumoro? I've added an example image to my post showing the result I get from my code, and just to be sure I understand you're saying you see the field expanding to fill the widget? – Hifi

A picture is worth a thousand words! Looks like I didn't quite understand your problem correctly. Please see my solution below. – Velasquez

Answer 1

It seems that, by default, a QFormLayout will only resize the height of its fields according to their sizeHint.

To change this behaviour, adjust the vertical stretch as appropriate:

policy = widg.sizePolicy()
policy.setVerticalStretch(1)
widg.setSizePolicy(policy)

Velasquez

Answer 2

You should set the object in the last row of formlayout (see QPlainTextEdit), its vertical Stretch factor should not be 0.

Ihram

Answer 3

This works for me: it is small at the time of calculating the initial size of the dialog widget and can grow with the dialog once it is already visible

class q2text(QTextEdit):
    def showEvent(self, ev):
        self.updateGeometry()
        return super().showEvent(ev)

    def sizeHint(self):
        if self.isVisible():
            return QSize(99999, 99999)
        else:
            return super().sizeHint()

Djebel