drag and drop between vanilla lists

[gferreira]

dear vanilla experts,

I’m trying to build a simple drag and drop interface using vanilla:

• the left column contains group names (dict keys), the right column contains list items
• I would like to copy items into groups (dict values) by selecting them in the right column and dragging them on top of group names in the left column

is this possible?

my current code is below. the dragging part seems to work, but the dragged items can’t be dropped on top of items in the other list.

from vanilla import *
from AppKit import NSDragOperationCopy

genericListPboardType = "genericListPboardType"

class DragAndDropListItemsDemo:

    weekdays = {
        'Mon' : [],
        'Tue' : [],
        'Wed' : [],
        'Thu' : [],
        'Fri' : [],
        'Sat' : [],
        'Sun' : [],
    }

    def __init__(self):
        self.w = Window((400, 200), 'drag & drop demo')
        self.w.list1 = List((0, 0, 200, -0),
                list(self.weekdays.keys()),
                allowsMultipleSelection=True,
                selectionCallback=self.list1SelectionCallback,
                selfWindowDropSettings=dict(type=genericListPboardType,
                        allowDropOnRow=True,
                        allowDropBetweenRows=False,
                        operation=NSDragOperationCopy,
                        callback=self.selfDropCallback))
        self.w.list2 = List((200, 0, -0, -0),
                ['banana', 'apple', 'orange', 'melon'],
                dragSettings=dict(type=genericListPboardType,
                        allowDropOnRow=True,
                        allowDropBetweenRows=False,
                        callback=self.dragCallback))
        self.w.open()

    def list1SelectionCallback(self, sender):
        selection = sender.getSelection()
        selectionKeys = [day for i, day in enumerate(sender.get()) if i in selection]
        for k in selectionKeys:
            print(k, self.weekdays[k])

    def dragCallback(self, sender, indexes):
        print('dragging…', indexes)

    def selfDropCallback(self, sender, dropInfo):
        isProposal = dropInfo["isProposal"]
        if not isProposal:
            print('dropped!')
            return True
            
DragAndDropListItemsDemo()

thanks in advance for any hints!

[gferreira]

@RafaŁ-Buchner that’s it!! thank you very much.

[RafaŁ Buchner]

I think that dragging callback always has to return True, maybe the first line return True is not necessary then

[RafaŁ Buchner]

Something like this?

from vanilla import *
from AppKit import NSDragOperationCopy

genericListPboardType = "genericListPboardType"

class DragAndDropListItemsDemo:

    weekdays = {
        'Mon' : [],
        'Tue' : [],
        'Wed' : [],
        'Thu' : [],
        'Fri' : [],
        'Sat' : [],
        'Sun' : [],
    }

    def __init__(self):
        self.w = Window((400, 200), 'drag & drop demo')
        self.w.list1 = List((0, 0, 200, -0),
                list(self.weekdays.keys()),
                allowsMultipleSelection=True,
                selectionCallback=self.list1SelectionCallback,
                selfWindowDropSettings=dict(type=genericListPboardType,
                        allowDropOnRow=True,
                        allowDropBetweenRows=False,
                        operation=NSDragOperationCopy,
                        callback=self.selfDropCallback))
        self.w.list2 = List((200, 0, -0, -0),
                ['banana', 'apple', 'orange', 'melon'],
                dragSettings=dict(type=genericListPboardType,
                        allowDropOnRow=True,
                        allowDropBetweenRows=False,
                        callback=self.dragCallback))
        self.w.open()

    def list1SelectionCallback(self, sender):
        selection = sender.getSelection()
        selectionKeys = [day for i, day in enumerate(sender.get()) if i in selection]
        for k in selectionKeys:
            print(k, self.weekdays[k])

    def dragCallback(self, sender, indexes):
        # print('dragging…', indexes)
        self.draggedItems = [self.w.list2.get()[i] for i in indexes]

    def selfDropCallback(self, sender, dropInfo):
        isProposal = dropInfo["isProposal"]
        if not isProposal:
            key = self.w.list1.get()[dropInfo['rowIndex']]
            for item in self.draggedItems:
                if item not in self.weekdays[key]:
                    self.weekdays[key] += [item]
            print(self.weekdays)
            return True
        return True

DragAndDropListItemsDemo()