[FIXED] How do you set the column width on a QTreeView?

Issue

Bear with me, I'm still new to QT and am having trouble wrapping my brain around how it does things.

I've created and populated a QTreeView with two columns:

class AppForm(QMainWindow):
    def __init__(self, parent = None):
        super(AppForm, self).__init__(parent)
        self.model = QStandardItemModel()
        self.view = QTreeView()
        self.view.setColumnWidth(0, 800)
        self.view.setEditTriggers(QAbstractItemView.NoEditTriggers)
        self.view.setModel(self.model)
        self.setCentralWidget(self.view)

Everything's working great, except the columns are extremely narrow. I hoped that setColumnWidth(0, 800) would widen the first column, but it doesn't seem to be having any effect. What's the proper method for setting column widths?

Solution

When you call setColumnWidth, Qt will do the equivalent of:

self.view.header().resizeSection(column, width)

Then, when you call setModel, Qt will (amongst other things) do the equivalent of:

self.view.header().setModel(model)

So the column width does get set - just not on the model the tree view ends up with.

tl;dr: set the column width after you set the model.

EDIT

Here's a simple demo script based on your example:

from PyQt4 import QtGui, QtCore

class Window(QtGui.QMainWindow):
    def __init__(self):
        QtGui.QMainWindow.__init__(self)
        self.model = QtGui.QStandardItemModel()
        self.view = QtGui.QTreeView()
        self.view.setEditTriggers(QtGui.QAbstractItemView.NoEditTriggers)
        self.view.setModel(self.model)
        self.setCentralWidget(self.view)
        parent = self.model.invisibleRootItem()
        for item in 'One Two Three Four'.split():
            parent.appendRow([
                QtGui.QStandardItem(item),
                QtGui.QStandardItem(),
                QtGui.QStandardItem(),
                ])
        self.view.setColumnWidth(0, 800)

if __name__ == '__main__':

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

Answered By - ekhumoro