Drag & Drop Implementation howto

[AGS]

Hi,

I would like to implement drag & drop accross different windows into my filemanager(s) (each is a window) and am unsure how this might work.

The "drag" part however already works. Unsureness concerns the "drop" part. As the drag & drop is handled by the window class, which is responbsible for reading mouse pos and drawing the dragged item(s), the "drop" part would work basically like this:

- window class checks mousbutton release
- window class uses WhichLayer() and looks it up in the list of window instances to find the window of the filemanager over which the content is dropped
- window class gets the pointer to the window object from wd_Userdata and traverses the list of all other objects that are attached to that window to find out which object in detail is under the mouse. for this any object that is a valid dropzone has a special bit set, just for the case that two or more objects are nested (like a frame object and a button in it) so that we know which one of those is a valid receiver of the "drop"

Now the question is, what message should be sent to that object? Basically that object and its window may belong to any app that runs under this GUI engine. However the destination object must know that the drop comes from a filemanager object and its address.

Any ideas you wish to share?

A

[mritter0]

Have you gotten this to work? I could use drag&drop in my project, too.

[AGS]

I did, however mine is based on my GUI-engine (custom non-OS gadgets etc). The part that you might find useful is the call to WhichLayer() to find the window that is currently under the mouse where you release the button (drop). And the part that saves a rectangle from the screen and draws the dragged object there.

[mritter0]

Hmmm.....not ReAction compatible.....I would still like to see a demo of it, if you don't mind. PM me for email details.