Can't change size within layout

Question

Well, I have a text editor with a button above it... I want the text editor to be inside a layout so that it increases and decreases its size the the QDialog, but I don't want to do that same with the button, which, by the way, doesn't have the size that I want and can't change it. What can I do?

Code:

from PyQt4 import QtCore, QtGui
import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *
class TextEditorDlg(QDialog):
    def __init__(self, parent=None):
        QtGui.QDialog.__init__(self, parent)
        self.resize(500, 400)
        self.Grid = QtGui.QGridLayout(self)
        self.button = QtGui.QPushButton(self)
        self.Grid.addWidget(self.button, 0, 0)
        self.lineEdit = QtGui.QLineEdit(self)
        self.textEdit = QtGui.QTextEdit(self)
        self.Grid.addWidget(self.lineEdit, 1, 0)
        self.Grid.addWidget(self.textEdit, 2, 0)
if __name__ == '__main__':
    app = QApplication(sys.argv)
    myapp = TextEditorDlg()
    myapp.show()
    sys.exit(app.exec_())

See the problem now?

Answer 1

First of all I do not understand why you are using a QGridLayout. Do you realize that you are not using the grid at all? You should simply use a QVBoxLayout.

Anyway, as I mentioned in a comment, you can probably obtain your desired "output" using a QHBoxLayout and the addStretch methods:

import sys
from PyQt4 import QtCore, QtGui


class TextEditorDlg(QtGui.QDialog):
    def __init__(self, parent=None):
        super(TextEditorDlg, self).__init__(parent)
        self.resize(500, 400)

        self.button = QtGui.QPushButton(self)
        self.lineEdit = QtGui.QLineEdit(self)
        self.textEdit = QtGui.QTextEdit(self)

        self.button_layout = QtGui.QHBoxLayout()
        self.button_layout.addStretch()
        self.button_layout.addWidget(self.button)
        self.button_layout.addStretch()

        self.grid = QtGui.QGridLayout(self)

        self.grid.addLayout(self.button_layout, 0, 0)
        self.grid.addWidget(self.lineEdit, 1, 0)
        self.grid.addWidget(self.textEdit, 2, 0)

        # Alternative using QVBoxLayout:
        #self.layout = QtGui.QVBoxLayout(self)
        #self.layout.addLayout(self.button_layout)
        #self.layout.addWidget(self.line_edit)
        #self.layout.addWidget(self.text_edit)



if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    myapp = TextEditorDlg()
    myapp.show()
    sys.exit(app.exec_())

You can tune the stretch amount passing an integer to addStretch.

If you wanted to use a QGridLayout to place the button in a specific position, then you should have done something like this:

import sys
from PyQt4 import QtCore, QtGui


class TextEditorDlg(QtGui.QDialog):
    def __init__(self, parent=None):
        super(TextEditorDlg, self).__init__(parent)
        self.resize(500, 400)

        self.button = QtGui.QPushButton(self)
        self.lineEdit = QtGui.QLineEdit(self)
        self.textEdit = QtGui.QTextEdit(self)

        self.grid = QtGui.QGridLayout(self)

        # Use the row-span and column-span arguments!
        self.grid.addWidget(self.button, 0, 0, 1, 1)
        self.grid.addWidget(self.lineEdit, 1, 0, 1, 3)
        self.grid.addWidget(self.textEdit, 2, 0, 1, 3)



if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    myapp = TextEditorDlg()
    myapp.show()
    sys.exit(app.exec_())

You can place the button exactly where you want using the correct row and column indexes and row-span and column-span values.

---

Edit: If you want to change the size of the QPushButton you must change the QSizePolicy of the button and the policy of the QTextEdit. For example:

import sys
from PyQt4 import QtCore, QtGui


class TextEditorDlg(QtGui.QDialog):
    def __init__(self, parent=None):
        super(TextEditorDlg, self).__init__(parent)
        self.resize(500, 400)

        self.button = QtGui.QPushButton(self)
        self.button.setSizePolicy(QtGui.QSizePolicy.Preferred, QtGui.QSizePolicy.Expanding)
        self.lineEdit = QtGui.QLineEdit(self)
        self.textEdit = QtGui.QTextEdit(self)
        self.textEdit.setSizePolicy(QtGui.QSizePolicy.Preferred, QtGui.QSizePolicy.Minimum)

        self.grid = QtGui.QGridLayout(self)

        # Use the row-span and column-span arguments!
        self.grid.addWidget(self.button, 0, 0, 3, 1)
        self.grid.addWidget(self.lineEdit, 3, 0, 1, 3)
        self.grid.addWidget(self.textEdit, 4, 0, 1, 3)



if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    myapp = TextEditorDlg()
    myapp.show()
    sys.exit(app.exec_())

You'll see that the button is bigger. You can control how big by changing the row-span. In the line self.grid.addWidget(self.button, 0, 0, 3, 1) increasing/decreasing the 3 will increase/decrease the vertical size(actually the number of rows occupied by the widget) and increasing/decreasing the 1 will change the horizontal size.

Note that if you place the widget at row 0 spanning for 3 rows then you have to be carefully to not create collisions adding new widgets to the layout.