It seems most people are asking how to make their QMainWindow
resize to its contents - I have the opposite problem, my MainWindow does resize and I don't know why.
When I set my QLabel
to a longer text, my mainwindow suddenly gets bigger, and I can't find out why that happens.
The following example code basically contains:
- A
QMainWindow
- A
QWidget
as central widget- A
QVBoxLayout
as a child of that- A
LabelBar
inside that.
- A
- A
- A
The LabelBar
is a QWidget
which in turn contains:
- A
QHBoxLayout
- Two
QLabel
s in that.
- Two
After a second, a QTimer
sets the label to a longer text to demonstrate the issue.
PyQt example code:
from PyQt5.QtWidgets import (QApplication, QHBoxLayout, QLabel, QWidget,
QMainWindow, QVBoxLayout, QSizePolicy)
from PyQt5.QtCore import QTimer
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
cwidget = QWidget(self)
self.setCentralWidget(cwidget)
self.resize(100, 100)
vbox = QVBoxLayout(cwidget)
vbox.addWidget(QWidget())
self.bar = LabelBar(self)
vbox.addWidget(self.bar)
timer = QTimer(self)
timer.timeout.connect(lambda: self.bar.lbl2.setText("a" * 100))
timer.start(1000)
class LabelBar(QWidget):
def __init__(self, parent=None):
super().__init__(parent)
hbox = QHBoxLayout(self)
self.lbl1 = QLabel(text="eggs")
hbox.addWidget(self.lbl1)
self.lbl2 = QLabel(text="spam")
hbox.addWidget(self.lbl2)
if __name__ == '__main__':
app = QApplication([])
main = MainWindow()
main.show()
app.exec_()
Main window grows because it's the goal of using layouts. Layouts make size requirements for their widgets to ensure that all content is displayed correctly. Requirements depend on child widgets. For example,
QLabel
by default grows horizontally and require space to fit its content. There are many ways to prevent window growing, and the resulting behavior varies:QLabel
in aQScrollArea
. When label's text is too long, scrollbars will appear.self.lbl2.setWordWrap(True)
. As long as you set text with some spaces,QLabel
will display it in several lines, and window will grow vertically a bit instead of growing horizontally.QLabel
's size hint usingself.lbl2.setSizePolicy(QSizePolicy.Ignored, QSizePolicy.Fixed)
.QLabel
's content will not affect its layout or parent widget size. Too large text will be truncated.