File I/O via Unity

Scripting
1

If I create a project that wants to save data to an external file - how is this done in a Unity app?

e.g. Save/Load user preferences in a INI file or retain game progress, level info and anything else that might be useful to have in permanent storage.

I know I can read in text data via TextAsset but how do I write out data and control the formatting (as in a INI file)?

2

You’ll have to use C#'s StreamReader and StreamWriter. Have to create your own method of writing and parsing the data though.

3

I don’t suppose anyone has already done this and created a few File i/o classes/functions that we can just plug into our projects?

4

Have a look at the various functions in System.IO. Note that this is related to Mono (.net), not C#.

–Eric

5

The more I grapple with this thing, the more fragmented the information sources seem to be and the steeper the learning curve becomes.

I dunno where on earth I got the idea this was going to be easy.

Thanks Eric for your pointer.

6

I just posted a sample StreamReader last night, check out the Road Reader class for how to read a text file from your asset bundle.

http://forum.unity3d.com/viewtopic.php?p=232729#232729

I didn’t know anything about .net I/O until I started this last night, though having 30 years of programming experience helped me to figure out the best (?) direction to go as I was learning.

Managed code is a lot easier than the old way, but the learning curve is indeed fiercer. dotnet / C# programming is the summation of 40 years of API and language design and the concepts are not easy to understand.

But with practice comes competency!

7

I just made a blog post showing some code how to do File I/O in a platform-independent way (working on both PC, Mac, iOS and Android):

8

As erique pointed out here, since Unity 3.3 there’s a way to do it without platform-specific code using #if statements.

Check the updated blog post for more information.

9

It is, actually. In your project settings set API Compatibility Level to .Net 2.0 and then use the standard .Net I/O functionality.

How to write files:

using (var writer = new BinaryWriter(File.Open(filename, FileMode.CreateNew)))
{
    writer.Write(123);
    writer.Write(123.456f);
    writer.Write("Hello, World!");
}

How to read files:

using (var reader = new BinaryReader(File.Open(filename, FileMode.Open)))
{
    var integer = reader.ReadInt32();
    var real = reader.ReadSingle();
    var text = reader.ReadString();
}

Also check File.ReadAllText, File.ReadAllLines, File.WriteAllText, File.WriteAllLines inside System.IO namespace.

1 Like
10

I’ve been looking into generating levels from text files and wondered where to find the System.IO api reference. Invaluable, thanks! :smile:

11

Just follow the link

12

any clue on how to generate levels using file IO ? been trying it for a while and am lost