Category Archives: C#

Unity3D and OnValidate

So, I came across MonoBehaviour method earlier today that I’d previously missed:

void OnValidate()

This is called when a script is loaded, or (editor only) when a parameter is changed via the inspector.  I’m using this to allow me to set a property that has a getter/setter via the inspector by using an extra variable.   I set the extra copy in the inspector, and then use code in OnValidate to copy it to the setter method.

I’m also going to use it instead of the Update method for my editor scripts – Update is called every time something changes in the editor, OnValidate, only when something on that script changes – much more effective.

Unity3D IAPs

I’ve been upgrading my Unity3D system to use the new Unity3D IAPS.  I’d been using a mixture of my own stuff on iOS and Unibill for Android, and wanted to clean up my code and simplify the cross-platform process.

Upgrading my code to reference UnityEngine.Purchasing system wasn’t too hard, but there was one thing I came across that cost me a lot of wasted time, the selected Store on Android.

For an Android build, you have a selection of store fronts you can support – Google Play, Amazon & Samsung.  (They just added a ‘Select Store at Runtime’ option too).

You make this selection using the Editor, but there is nothing to indicate what this selection is.  I had selected Amazon while messing around in the project, and promptly forgot I’d done that.  So when I finally called the code to initialize the purchase tokens, they would never authorize and always return ‘product not found’ error.  Initially I blamed this on the fact it can take Google Play 24 hours to activate a new purchase token, so I took a break…

The next day, the same problem, but I thought maybe the 24 hours wasn’t technically up yet, or maybe Google was taking longer than normal.  I pushed on with some other tasks, and checked the products by running the App from time to time on an Android device and watching ADB for the results – still nothing.

That’s when I remembered the store selector! I selected Google Play, rebuilt and presto, it worked! However, it would have been nice if either (or both)

(a) The Editor menu had a check mark beside the selected store

(b) The system spat out an ADB message with the name of the store it was checking

It also turns out you can select the store via a script, which I decided was the better option for me.



public AndroidStore androidStore;

is a property on a MonoBehaviour which creates a nice drop down in the inspector.

Non-breaking space in Unity3D/NGUI

I was messing with some text line wrapping an an app today, and needed to stop NGUI inserting a line break between a number and a label in a long string.  Using the escape sequence ‘\u00A0’ did the trick.

return category + "\u00A0#" + indexInCategory;

Now the last word in the string category and the number preceded with a # stay on the same line!

Note: I read that pressing ALT-Space on the Mac will insert this character.  It may do that, but MonoDevelop/NGUI don’t seem to care.  The escape literal worked, the ALT-Space just acted like a regular space.

Note: To insert a non-breaking space in a XML document without using Document Entities, use the following:  

Unity3D Application.persistentDataPath is null on Android

I’ve no idea why this is happening all of a sudden, but the static property Application.persistentDataPath is returning a zero length string and not the path to the storage folder on my Android devices.  From googling, I can see I’m not the only one with this problem.  It’s happening whether I build directly from Unity, or download it from the beta tab on Google Play.

I added the following method to my Android plugin JAR so at least I could move on and not get stuck:

    public static String PBgetFilePath(final Activity activity)
        File path = activity.getApplicationContext().getFilesDir();
        Log.i(LOGTAG,"Internal FilesDir: " + path.getPath());
        return path.getPath();

This returns the correct string and when I use it, I can read and write files as expected.  If persistentDataPath returns a null or a zero length string, then I call my java code and use the result.

UIButton and isEnabled color change

As part of my hidden UIWidget stuff, the widget has a few buttons on it that I set the isEnabled flag to false when appropriate.  This had the effect of the button changing over time to a dark gray color when it appears on screen.

I didn’t want the color to transition, I wanted it to start gray when it appeared.  So I added the following lines:

float oldDur = button.duration;
button.duration = 0;
button.isEnabled = false;
button.duration = oldDur;

That did the trick – button appeared gray and didn’t transition.