PyQt: LineEdit widget's placement inside of FormLayout

问题

A QtGui.QLineEdit line_edit widget is placed inside of QtGui.QFormLayout Form layout using .addRow() method.

my_formLayout.addRow(my_label, my_lineEdit) 

To make a line_edit widget to stick to a dialog window's edges (so it re-sizes with the dialog) tried using sizePolicy:

    sizePolicy = my_lineEdit.sizePolicy()
    sizePolicy.setHorizontalStretch(1)
    my_lineEdit.setSizePolicy( sizePolicy )

There are no errors. But the line_edit widget still doesn't stick to the edges of the dialog... What could be wrong?

回答1:

You shouldn't need to do anything.

This simple example resizes as necessary:

from PyQt4 import QtGui

class Dialog(QtGui.QDialog):
    def __init__(self):
        super(Dialog, self).__init__()
        form = QtGui.QFormLayout(self)
        label = QtGui.QLabel('Label', self)
        edit = QtGui.QLineEdit(self)
        form.addRow(label, edit)

if __name__ == '__main__':

    import sys
    app = QtGui.QApplication(sys.argv)
    window = Dialog()
    window.setGeometry(500, 300, 300, 50)
    window.show()
    sys.exit(app.exec_())

UPDATE:

Okay, it seems the behaviour of QFormaLayout is platform-dependent. To quote from the docs:

Style based on the Mac OS X Aqua guidelines. Labels are right-aligned, the fields don't grow beyond their size hint, and the form is horizontally centered.

However, there is a setFieldGrowthPolicy method, which could be used to over-ride the default behaviour on Mac OSX. So try:

    my_formLayout.setFieldGrowthPolicy(QtGui.QFormLayout.ExpandingFieldsGrow)

or:

    my_formLayout.setFieldGrowthPolicy(QtGui.QFormLayout.AllNonFixedFieldsGrow)

回答2:

Try this: sizePolicy.setHorizontalPolicy(QSizePolicy.Expanding)

来源：https://stackoverflow.com/questions/21467262/pyqt-lineedit-widgets-placement-inside-of-formlayout