Question Implementing a file drag and drop system - Unity UI [CLOSED, UNANSWERED (Read last post)]

Hiya - simple question (but i'm imagining not the answer ) - how can i Implement a file drag and drop system in unity?

A. i am already aware that there is a (partially) working drag and drop system for windows - however this does not include mac and linux - i'm also aware there is another system but i'm not willing to pay £13 for it (because this should definetly not require me to pay to use a drag and drop system - and this system still doesn't include linux)

B. if somehow this is even possible - can i limit the system to only work in a particular place within my UI (i.e a circle)?

Thankyou in advance!

 

Simple answer!



Tutorials and example code are great, but keep this in mind to maximize your success and minimize your frustration:

How to do tutorials properly, two (2) simple steps to success:

Step 1. Follow the tutorial and do every single step of the tutorial 100% precisely the way it is shown. Even the slightest deviation (even a single character!) generally ends in disaster. That's how software engineering works. Every step must be taken, every single letter must be spelled, capitalized, punctuated and spaced (or not spaced) properly, literally NOTHING can be omitted or skipped.

Fortunately this is the easiest part to get right: Be a robot. Don't make any mistakes.
BE PERFECT IN EVERYTHING YOU DO HERE!!

If you get any errors, learn how to read the error code and fix your error. Google is your friend here. Do NOT continue until you fix your error. Your error will probably be somewhere near the parenthesis numbers (line and character position) in the file. It is almost CERTAINLY your typo causing the error, so look again and fix it.

Step 2. Go back and work through every part of the tutorial again, and this time explain it to your doggie. See how I am doing that in my avatar picture? If you have no dog, explain it to your house plant. If you are unable to explain any part of it, STOP. DO NOT PROCEED. Now go learn how that part works. Read the documentation on the functions involved. Go back to the tutorial and try to figure out WHY they did that. This is the part that takes a LOT of time when you are new. It might take days or weeks to work through a single 5-minute tutorial. Stick with it. You will learn.

Step 2 is the part everybody seems to miss. Without Step 2 you are simply a code-typing monkey and outside of the specific tutorial you did, you will be completely lost. If you want to learn, you MUST do Step 2.

Of course, all this presupposes no errors in the tutorial. For certain tutorial makers (like Unity, Brackeys, Imphenzia, Sebastian Lague) this is usually the case. For some other less-well-known content creators, this is less true. Read the comments on the video: did anyone have issues like you did? If there's an error, you will NEVER be the first guy to find it.

Beyond that, Step 3, 4, 5 and 6 become easy because you already understand!

Finally, when you have errors...

Remember: NOBODY here memorizes error codes. That's not a thing. The error code is absolutely the least useful part of the error. It serves no purpose at all. Forget the error code. Put it out of your mind.

The complete error message contains everything you need to know to fix the error yourself.

The important parts of the error message are:

- the description of the error itself (google this; you are NEVER the first one!)
- the file it occurred in (critical!)
- the line number and character position (the two numbers in parentheses)
- also possibly useful is the stack trace (all the lines of text in the lower console window)

Always start with the FIRST error in the console window, as sometimes that error causes or compounds some or all of the subsequent errors. Often the error will be immediately prior to the indicated line, so make sure to check there as well.

All of that information is in the actual error message and you must pay attention to it. Learn how to identify it instantly so you don't have to stop your progress and fiddle around with the forum.

 

This (the results from google you have given) is a drag and drop system for ui elements - not for files...

I need to grab files from the users machine - specifically audio files

 

Ok 1 step closer - checkout these linkies!

https://docs.unity3d.com/ScriptReference/DragAndDrop.html
https://docs.unity3d.com/ScriptReference/DragAndDrop.AddDropHandler.html
https://docs.unity3d.com/ScriptReference/DragAndDrop.AcceptDrag.html

 

However im not sure of support between different OS's but given this seems to be a unity specific class i'd assume it may work - currently however draggin an mp3 onto the game window produces "Dragging upon Assets/Scripts/Audio 24990"

 

Ok just realised UnityEditor only works for things.... in the editor (i.e the heirarchy window not the game tab)

Additional alternatives (and some interesting links) here for now - but i'm determined to solve this!

- https://stackoverflow.com/questions...pen-windows-explorer-in-select-open-file-mode
- https://www.google.com/search?client=firefox-b-d&q=Open+File+Dialog+++Unity
- https://docs.unity3d.com/ScriptReference/EditorUtility.OpenFilePanel.html (i think this won't work in a build because it's editor utility)
- https://forum.unity.com/threads/openfiledialog-in-runtime.459474/

 

This works for only windows (and in build)
https://assetstore.unity.com/packages/tools/input-management/file-hopper-129029

There's of course file explorers such as this one
https://assetstore.unity.com/packages/tools/gui/runtime-file-browser-113006

Mac and linux are looking increasignly hard to do however - a feature request has already been put in here
Feature Request - External object drag and drop - Unity Forum

 

There's also a linux, mac, windows standalone explorer but im not sure wether it works given the amount of issues https://github.com/gkngkc/UnityStandaloneFileBrowser
The webGL demo seems to work: https://gkngkc.github.io/

update: Will continue searching tmoz - jee i hope this gets implemented soon i really need it

 

Well after having a large lookaround yestarday and a bit today the only real """solutions""" i can form are

A.1. using python with unity when the package becomes available (however i don't know how long this will be and if it will even support runtime or build which is of course a massive issue) - then checking if the user drags any files and if the unity window is focused grab the data from the dragged file and import it into unity (somehow? - i'm not sure how you'd even convert this data into a unity type such as an AudioClip or Texture2D) - you could even grab the data as soon as the user drags a file then check if the game window is focused and the mouse "let go of" whilst in the window to simulate a drag and drop - but of course you'd still need to manually handle each OS in python and this doesn't support specific locations in the window unless you hard code it into the python file or can somehow feed inputs to the python file

and that's an utterly stupid scope for a simple feature....

and it doesn't account for huge security concerns such as if the game can access the deletion of files - this would hopefully be handled with user access levels on the python extensions end - but then that raises the question of if these user access levels also restrict grabbing data from dragged files - because that could bassically result in a file grabber which is also unsafe!

unless of course unity implemented there own feature for file explorers and a drag and drop system (*hint*, *hint*) like they have done for the UnityEditor class only of course these systems would need to occur at runtime AND work in editor + builds and the drag and drop system could be limited to a box colliders dimensions

A.2. you could tell the user to copy a file at runtime then use an application like clipboard in python to register the data into unity - there might be a way to handle clipboard data in csharp - but of course this isn't drag and drop nor a file explorer (which isn't ideal for UX) and again i doubt this is easy to handle cross platform (and of course all of the above is a huge problem)

B. As this website states even if you want a file explorer not a drag and drop system you'd have to go about writing your own .NET solution (which seems silly to me - there must be a reliable way to handle grabbing of files - i thought drag and drop would be hard to do but now i'm coming to realise even a file explorer for all platforms seems impossible at this current time)

C. Use assets from the asset store (which isn't ideal as most of them are paid or sometimes broken - same goes for github - except the paid part )

As of 28.07.22 this is all i could find - im marking the thread as CLOSED for now but i'll leave comments open in the vague hope a solution is found soon - i reccomend you checkout the feature request if you are also facing this problem

Good luck to anyone else trying to combat this problem - whether it be a file explorer or drag and drop system!

 

Honestly, you're a true hero for trying. I have nothing but respect for you man. Thanks for the Linux, Mac, and Windows standalone explorer. I found that pretty useful. I also wish good luck to anyone else combating this problem.