pyGTK/GTK 文件选择器 - 是否可以在文件或文件夹写入磁盘前验证用户输入？

Question

我想在创建新文件夹时，检查用户选择的文件夹名称是否有效，这个操作是在gtk.FileChooser对话框中进行的。
我尝试连接到对话框的“响应”信号，但那时候已经太晚了，新文件夹已经写入磁盘了。
有没有其他方法可以在写入磁盘之前验证文件夹名称，而不是等写完后再检查？

感谢Mark... 这是我正在使用的代码：

import gtk

def _newFolderDialog(currentFolder=None):

    newDialog = gtk.FileChooserDialog(
        title="Create new folder", parent=None, 
        action=gtk.FILE_CHOOSER_ACTION_CREATE_FOLDER, 
        buttons= (gtk.STOCK_CANCEL, gtk.RESPONSE_CANCEL), backend=None)
    newButton = newDialog.add_button(gtk.STOCK_NEW, gtk.RESPONSE_OK)
    if currentFolder is not None:
        newDialog.set_current_folder(currentFolder)

    newButton.connect("pressed", validateChoice, newDialog)

    response = newDialog.run()

    if response == gtk.RESPONSE_OK:
        newFolder = newDialog.get_filename()
        newDialog.destroy()
        return newFolder

    elif response == 1: # Validation was not satisfied
        msg = gtk.MessageDialog(parent=None, flags=gtk.DIALOG_MODAL,
            type=gtk.MESSAGE_ERROR, buttons=gtk.BUTTONS_OK, 
            message_format="Try again!")
        msg.run()
        msg.destroy()
        current_folder = newDialog.get_current_folder()
        newDialog.destroy()
        return _newFolderDialog(current_folder)

    elif response == 2: # Ok button was pressed, but with no entry
        current_folder = newDialog.get_current_folder()
        newDialog.destroy()
        return _newFolderDialog(current_folder)

    elif response == gtk.RESPONSE_CANCEL:
        newDialog.destroy()
        return None

def validateChoice(button, dialog):
    newFolder = dialog.get_filename()

    if newFolder is None: # The cursor was in the empty text entry box
        dialog.response(2)
    else:
        # If cursor is selecting a folder, lets unselect it, we are intereste
        # in the value in the entry text box.
        dialog.unselect_filename(newFolder) 
        newFolder = dialog.get_filename()

        if newFolder is None: # A folder was selected but empty text entry box
            dialog.response(2)

        ## do some validation, in this case the folder has to start with "/home"
        elif not newFolder.startswith("/home"):  
            dialog.response(1)
        else:
            dialog.response(gtk.RESPONSE_OK)

newFolder = _newFolderDialog()
print newFolder

Answer 1

我看到有几种方法可以做到这一点。

第一种方法是自己写一个响应 ID 的处理器，而不是使用 gtk.RESPONSE_OK（这个对小部件来说意味着创建文件夹）。如果你选择这种方式，你就需要在验证后自己负责实际创建文件夹（可以用 os.path.mkdir）。

第二种方法是可以重写“新建”按钮的点击事件：

import gtk

def new_button_pressed(widget, data=None):
    ## data is a reference to the dialog widget
    ## do some validation, in this case the folder has to start with "/home"
    if not(data.get_filename().startswith("/home")):
        ## force cancel response
        print "failed validation..."        
        data.response(gtk.RESPONSE_CANCEL)
    else:
        print "success validation..."
        data.response(gtk.RESPONSE_OK)

newDialog = gtk.FileChooserDialog(
title="Create new folder", parent=None, 
action=gtk.FILE_CHOOSER_ACTION_CREATE_FOLDER, 
buttons= (gtk.STOCK_CANCEL, gtk.RESPONSE_CANCEL), backend=None)
new_button = newDialog.add_button(gtk.STOCK_NEW, gtk.RESPONSE_OK)
new_button.connect("pressed", new_button_pressed, newDialog)
newDialog.run()