wxPython – EnsureVisible() method in wx.TreeCtrl

In this article we are going to learn about EnsureVisible() function associated with wx.TreeCtrl class of wxPython. EnsureVisible() method makes an item/root to be visible on screen. Scrolls and/or expands items to ensure that the given item is visible.

This method can be used, and will work, even while the window is frozen (see wx.Window.Freeze ).

Syntax: wx.TreeCtrl.EnsureVisible()

Parameters:

Parameter	Type	Description
item	wx.TreeItemId	item that we want to ensure to be visible.

Code Example:

Python3

import wx

class TreePanel(wx.Panel):

    def __init__(self, parent):
        wx.Panel.__init__(self, parent)

        self.tree = wx.TreeCtrl(self, wx.ID_ANY, wx.DefaultPosition, (100, 50),
                           wx.TR_HAS_BUTTONS)
        # create tree root
        self.root = self.tree.AddRoot('root')
        self.tree.SetPyData(self.root, ('key', 'value'))

        # add items to root
        item = self.tree.AppendItem(self.root, "Item")
        item2 = self.tree.AppendItem(self.root, "Item")
        item3 = self.tree.AppendItem(self.root, "Item")
        item4 = self.tree.AppendItem(self.root, "Item")
        focusitem = self.tree.AppendItem(self.root, "Focus Item")

        # expand root
        self.tree.Expand(self.root)

        self.tree.EnsureVisible(focusitem)

        sizer = wx.BoxSizer(wx.VERTICAL)
        sizer.Add(self.tree, 0, wx.EXPAND)
        self.SetSizer(sizer)

    def onclick(self, e):
        # Delete si2 from the tree
        self.tree.Delete(self.si2)


class MainFrame(wx.Frame):

    def __init__(self):
        wx.Frame.__init__(self, parent = None, title ='TreeCtrl Demo')
        panel = TreePanel(self)
        self.Show()


if __name__ == '__main__':
    app = wx.App(redirect = False)
    frame = MainFrame()
    app.MainLoop()

Output: