Ever wonder how some unity extensions show a notification overlay? Check out the EditorWindow.ShowNotification method. 

You can get access to the build order for scenes in your editor scripts by calling EditorBuildSettings.scenes. This allows you to control what scenes are included with the build through your editor code.

    public class SceneDump
    {
        [MenuItem("Codefarts/Dump Scenes")]
        public static void Dump()
        {
            var parts = from part in EditorBuildSettings.scenes
                        select string.Format("{0} - {1}", part.enabled, part.path);

            Debug.Log(string.Join("\r\n", parts.ToArray()));
        }
    }

I'll be heading to High Level, Alberta May 26, 2013 to do some Morel picking for at least a few weeks. The last time I went Morel picking was about 6+ years ago so it will be fun to try it again.

Need to send simulated user input to the game window? Unity provides the EditorGUIUtility.QueueGameViewInputEvent method for doing just that. Using this method you could construct a utility that captures and plays back user input as your game is running which would be handy for debugging and unit testing purposes.

Below is a simple bit of code that will attempt to retrieve the asset path of the prefab stored on disk. The method will also try to walk up the prefab hierarchy if the prefab parameter appears to be a instance of the original. 

/// <summary>
/// Gets the source path to a prefab if any.
/// </summary>
/// <param name="prefab">The prefab reference to get the asset path for.</param>
/// <returns>Returns a asset path for a prefab.</returns>
/// <remarks>This method will attempt to find the source asset of the given <see cref="UnityEngine.Object"/> by 
/// walking up the parent prefab hierarchy.</remarks>
public static string GetSourcePrefab(UnityEngine.Object prefab)
{
    // if no prefab specified then return null
    if (prefab == null)
    {
        return null;
    }

    // attempt to get the path
    var path = AssetDatabase.GetAssetPath(prefab);

    // if no path returned it may be an instantiated prefab so try to get the parent prefab
    while (String.IsNullOrEmpty(path))
    {
        // try parent prefab
        var parent = PrefabUtility.GetPrefabParent(prefab);
                
        // no parent so must be generated through code so just exit loop
        if (parent == null)
        {
            break;
        }

        // attempt to get path for 
        path = AssetDatabase.GetAssetPath(parent);

        // set prefab reference to parent for next loop
        prefab = parent;
    }

    // return the path if any
    return path;
}

If you have some editor scripts and you want to detect weather or not unity has compiled your scripts you can try this simple method.

Created a private class within your editor window and declare a field of that private class.

public class YourEditor : EditorWindow
{
    private RecompileClass recompile;

    private class RecompileClass
    {  
    }
}

In the OnGUI method (or where appropriate) perform a check to see if the field is null. If it’s null you can assume that unity compiled your scripts again so do what you need to do is create a new instance of the private class and assign it to the field.

public class YourEditor : EditorWindow
{
    private RecompileClass recompile;
      
    private class RecompileClass
    {
    }

    public void OnGUI()
    {
        // check if recompile variable is null 
        if (this.recompile == null  )
        {
            // if yes assume recompile then create a reference to a recompile class 
            this.recompile = new RecompileClass();

            // do what you need to do here after detecting a recompile  
        }

        // do regular stuff here
    }
}

The next time unity recompiles your scripts the field will loose it’s reference and will be null again.

    using System;
    using System.Collections.Generic;

    /// <summary>
    /// Implements a generic equality comparer that uses a callback to perform the comparison.
    /// </summary>
    /// <typeparam name="T">The type we want to compare.</typeparam>
    public class EqualityComparerCallback<T> : IEqualityComparer<T>
    {
        /// <summary>
        /// Holds a reference to the callback that handles comparisons.
        /// </summary>
        private readonly Func<T, T, bool> function;

        /// <summary>
        /// Holds a reference to the callback used to calculate hash codes.
        /// </summary>
        private Func<T, int> hashFunction;
      
        /// <summary>
        /// Initializes a new instance of the <see cref="EqualityComparerCallback{T}"/> class.
        /// </summary>
        /// <param name="func">
        /// The callback function that will do the comparing.
        /// </param>
        /// <exception cref="ArgumentNullException">
        /// Throws a <see cref="ArgumentNullException"/> if the <see cref="func"/> parameter is null.
        /// </exception>
        public EqualityComparerCallback(Func<T, T, bool> func)
        {
            if (func == null)
            {
                throw new ArgumentNullException("func");
            }

            this.function = func;
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="EqualityComparerCallback{T}"/> class.
        /// </summary>
        /// <param name="func">
        /// The callback function that will do the comparing.
        /// </param>
        /// <param name="hash">
        /// The callback function that will return the hash code.
        /// </param>  
        public EqualityComparerCallback(Func<T, T, bool> func, Func<T, int> hash)
            : this(func)
        {
            this.hashFunction = hash;
        }

        /// <summary>
        /// Gets or sets the callback function to use to compute the hash.
        /// </summary>
        public Func<T, int> HashFunction
        {
            get
            {
                return this.hashFunction;
            }

            set
            {
                this.hashFunction = value;
            }
        }
                  
        /// <summary>
        /// Provides a static method for returning a <see cref="EqualityComparerCallback{T}"/> type.
        /// </summary>
        /// <param name="func">
        /// The callback function that will do the comparing.
        /// </param>
        /// <returns>Returns a new instance of a <see cref="EqualityComparerCallback{T}"/> type.</returns>
        public static IEqualityComparer<T> Compare(Func<T, T, bool> func)
        {
            return new EqualityComparerCallback<T>(func);
        }

        /// <summary>
        /// Determines whether the specified object instances are considered equal.
        /// </summary>
        /// <param name="x">The first object to compare.</param>
        /// <param name="y">The second object to compare.</param>
        /// <returns>True if the objects are considered equal otherwise, false. If both objA and objB are null, the method returns true.</returns>
        public bool Equals(T x, T y)
        {
            return this.function(x, y);
        }    

        /// <summary>
        /// The get hash code for a object.
        /// </summary>
        /// <param name="obj">
        /// The object whose hash code will be computed.          
        /// </param>
        /// <returns>
        /// Returns a <see cref="int"/> value representing the hash code.
        /// </returns>
        /// <remarks>If no callback function was set for the <see cref="HashFunction"/> the object default <see cref="GetHashCode"/> method will be used.</remarks>
        public int GetHashCode(T obj)
        {
            if (this.hashFunction == null)
            {
                return obj.GetHashCode();
            }

            return this.hashFunction(obj);
        }
    }

A usage scenario

    // build a list of unique categories
    var list = new List<string>();
    foreach (var rule in this.rules)
    {
        if (string.IsNullOrEmpty(rule.Category ?? string.Empty))
        {
            continue;
        }

        // check if already exists
        if (list.Contains(rule.Category, new EqualityComparerCallback<string>((a, b) => a.Trim() == b.Trim())))
        {
            continue;
        }
    }
    return list.ToArray();

Not a unity specific tip but still a handy unity helper for opening a unity project from file explorer. *Works only for windows platforms.* Download the OpenInUnity.reg file below or open up Notepad and paste the snippet below then save the file with a *.reg file extension. Next navigate to the file and right click on it and select “Merge” from the popup menu. You should now be able to open a unity project folder by right clicking on it in File Explorer and selecting “Open with Unity”.

OpenInUnity.reg (360.00 bytes)

OpenWithUnity64.reg (452.00 bytes)

For x86 unity use the snippet below

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\Folder\shell\Open with Unity\command]
@="\"C:\\Program Files (x86)\\Unity\\Editor\\unity.exe\" -projectPath \"%1\""

For 64bit unity use the snippet below

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\Folder\shell\Open with Unity\command]
@="\"C:\\Program Files\\Unity\\Editor\\unity.exe\" -projectPath \"%1\""

Simple solution to get a MIME type from a file extension. Source –> http://stackoverflow.com/a/7161265/341706

public static class MIMEAssistant
{
  private static readonly Dictionary<string, string> MIMETypesDictionary = new Dictionary<string, string>
  {
    {"ai", "application/postscript"},
    {"aif", "audio/x-aiff"},
    {"aifc", "audio/x-aiff"},
    {"aiff", "audio/x-aiff"},
    {"asc", "text/plain"},
    {"atom", "application/atom+xml"},
    {"au", "audio/basic"},
    {"avi", "video/x-msvideo"},
    {"bcpio", "application/x-bcpio"},
    {"bin", "application/octet-stream"},
    {"bmp", "image/bmp"},
    {"cdf", "application/x-netcdf"},
    {"cgm", "image/cgm"},
    {"class", "application/octet-stream"},
    {"cpio", "application/x-cpio"},
    {"cpt", "application/mac-compactpro"},
    {"csh", "application/x-csh"},
    {"css", "text/css"},
    {"dcr", "application/x-director"},
    {"dif", "video/x-dv"},
    {"dir", "application/x-director"},
    {"djv", "image/vnd.djvu"},
    {"djvu", "image/vnd.djvu"},
    {"dll", "application/octet-stream"},
    {"dmg", "application/octet-stream"},
    {"dms", "application/octet-stream"},
    {"doc", "application/msword"},
    {"docx","application/vnd.openxmlformats-officedocument.wordprocessingml.document"},
    {"dotx", "application/vnd.openxmlformats-officedocument.wordprocessingml.template"},
    {"docm","application/vnd.ms-word.document.macroEnabled.12"},
    {"dotm","application/vnd.ms-word.template.macroEnabled.12"},
    {"dtd", "application/xml-dtd"},
    {"dv", "video/x-dv"},
    {"dvi", "application/x-dvi"},
    {"dxr", "application/x-director"},
    {"eps", "application/postscript"},
    {"etx", "text/x-setext"},
    {"exe", "application/octet-stream"},
    {"ez", "application/andrew-inset"},
    {"gif", "image/gif"},
    {"gram", "application/srgs"},
    {"grxml", "application/srgs+xml"},
    {"gtar", "application/x-gtar"},
    {"hdf", "application/x-hdf"},
    {"hqx", "application/mac-binhex40"},
    {"htm", "text/html"},
    {"html", "text/html"},
    {"ice", "x-conference/x-cooltalk"},
    {"ico", "image/x-icon"},
    {"ics", "text/calendar"},
    {"ief", "image/ief"},
    {"ifb", "text/calendar"},
    {"iges", "model/iges"},
    {"igs", "model/iges"},
    {"jnlp", "application/x-java-jnlp-file"},
    {"jp2", "image/jp2"},
    {"jpe", "image/jpeg"},
    {"jpeg", "image/jpeg"},
    {"jpg", "image/jpeg"},
    {"js", "application/x-javascript"},
    {"kar", "audio/midi"},
    {"latex", "application/x-latex"},
    {"lha", "application/octet-stream"},
    {"lzh", "application/octet-stream"},
    {"m3u", "audio/x-mpegurl"},
    {"m4a", "audio/mp4a-latm"},
    {"m4b", "audio/mp4a-latm"},
    {"m4p", "audio/mp4a-latm"},
    {"m4u", "video/vnd.mpegurl"},
    {"m4v", "video/x-m4v"},
    {"mac", "image/x-macpaint"},
    {"man", "application/x-troff-man"},
    {"mathml", "application/mathml+xml"},
    {"me", "application/x-troff-me"},
    {"mesh", "model/mesh"},
    {"mid", "audio/midi"},
    {"midi", "audio/midi"},
    {"mif", "application/vnd.mif"},
    {"mov", "video/quicktime"},
    {"movie", "video/x-sgi-movie"},
    {"mp2", "audio/mpeg"},
    {"mp3", "audio/mpeg"},
    {"mp4", "video/mp4"},
    {"mpe", "video/mpeg"},
    {"mpeg", "video/mpeg"},
    {"mpg", "video/mpeg"},
    {"mpga", "audio/mpeg"},
    {"ms", "application/x-troff-ms"},
    {"msh", "model/mesh"},
    {"mxu", "video/vnd.mpegurl"},
    {"nc", "application/x-netcdf"},
    {"oda", "application/oda"},
    {"ogg", "application/ogg"},
    {"pbm", "image/x-portable-bitmap"},
    {"pct", "image/pict"},
    {"pdb", "chemical/x-pdb"},
    {"pdf", "application/pdf"},
    {"pgm", "image/x-portable-graymap"},
    {"pgn", "application/x-chess-pgn"},
    {"pic", "image/pict"},
    {"pict", "image/pict"},
    {"png", "image/png"}, 
    {"pnm", "image/x-portable-anymap"},
    {"pnt", "image/x-macpaint"},
    {"pntg", "image/x-macpaint"},
    {"ppm", "image/x-portable-pixmap"},
    {"ppt", "application/vnd.ms-powerpoint"},
    {"pptx","application/vnd.openxmlformats-officedocument.presentationml.presentation"},
    {"potx","application/vnd.openxmlformats-officedocument.presentationml.template"},
    {"ppsx","application/vnd.openxmlformats-officedocument.presentationml.slideshow"},
    {"ppam","application/vnd.ms-powerpoint.addin.macroEnabled.12"},
    {"pptm","application/vnd.ms-powerpoint.presentation.macroEnabled.12"},
    {"potm","application/vnd.ms-powerpoint.template.macroEnabled.12"},
    {"ppsm","application/vnd.ms-powerpoint.slideshow.macroEnabled.12"},
    {"ps", "application/postscript"},
    {"qt", "video/quicktime"},
    {"qti", "image/x-quicktime"},
    {"qtif", "image/x-quicktime"},
    {"ra", "audio/x-pn-realaudio"},
    {"ram", "audio/x-pn-realaudio"},
    {"ras", "image/x-cmu-raster"},
    {"rdf", "application/rdf+xml"},
    {"rgb", "image/x-rgb"},
    {"rm", "application/vnd.rn-realmedia"},
    {"roff", "application/x-troff"},
    {"rtf", "text/rtf"},
    {"rtx", "text/richtext"},
    {"sgm", "text/sgml"},
    {"sgml", "text/sgml"},
    {"sh", "application/x-sh"},
    {"shar", "application/x-shar"},
    {"silo", "model/mesh"},
    {"sit", "application/x-stuffit"},
    {"skd", "application/x-koan"},
    {"skm", "application/x-koan"},
    {"skp", "application/x-koan"},
    {"skt", "application/x-koan"},
    {"smi", "application/smil"},
    {"smil", "application/smil"},
    {"snd", "audio/basic"},
    {"so", "application/octet-stream"},
    {"spl", "application/x-futuresplash"},
    {"src", "application/x-wais-source"},
    {"sv4cpio", "application/x-sv4cpio"},
    {"sv4crc", "application/x-sv4crc"},
    {"svg", "image/svg+xml"},
    {"swf", "application/x-shockwave-flash"},
    {"t", "application/x-troff"},
    {"tar", "application/x-tar"},
    {"tcl", "application/x-tcl"},
    {"tex", "application/x-tex"},
    {"texi", "application/x-texinfo"},
    {"texinfo", "application/x-texinfo"},
    {"tif", "image/tiff"},
    {"tiff", "image/tiff"},
    {"tr", "application/x-troff"},
    {"tsv", "text/tab-separated-values"},
    {"txt", "text/plain"},
    {"ustar", "application/x-ustar"},
    {"vcd", "application/x-cdlink"},
    {"vrml", "model/vrml"},
    {"vxml", "application/voicexml+xml"},
    {"wav", "audio/x-wav"},
    {"wbmp", "image/vnd.wap.wbmp"},
    {"wbmxl", "application/vnd.wap.wbxml"},
    {"wml", "text/vnd.wap.wml"},
    {"wmlc", "application/vnd.wap.wmlc"},
    {"wmls", "text/vnd.wap.wmlscript"},
    {"wmlsc", "application/vnd.wap.wmlscriptc"},
    {"wrl", "model/vrml"},
    {"xbm", "image/x-xbitmap"},
    {"xht", "application/xhtml+xml"},
    {"xhtml", "application/xhtml+xml"},
    {"xls", "application/vnd.ms-excel"},                        
    {"xml", "application/xml"},
    {"xpm", "image/x-xpixmap"},
    {"xsl", "application/xml"},
    {"xlsx","application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"},
    {"xltx","application/vnd.openxmlformats-officedocument.spreadsheetml.template"},
    {"xlsm","application/vnd.ms-excel.sheet.macroEnabled.12"},
    {"xltm","application/vnd.ms-excel.template.macroEnabled.12"},
    {"xlam","application/vnd.ms-excel.addin.macroEnabled.12"},
    {"xlsb","application/vnd.ms-excel.sheet.binary.macroEnabled.12"},
    {"xslt", "application/xslt+xml"},
    {"xul", "application/vnd.mozilla.xul+xml"},
    {"xwd", "image/x-xwindowdump"},
    {"xyz", "chemical/x-xyz"},
    {"zip", "application/zip"}
  };

  public static string GetMIMEType(string fileName)
  {
    if (Path.GetExtension(fileName).Length > 1 && MIMETypesDictionary.ContainsKey(Path.GetExtension(fileName).Remove(0, 1)))
    {
      return MIMETypesDictionary[Path.GetExtension(fileName).Remove(0, 1)];
    }
    return "unknown/unknown";
  }
}

Unity comes with a helper method for generating a unique asset paths called AssetDatabase.GenerateUniqueAssetPath. The documentation for this method is rather minimal but the code example below should help you understand how to use it a little better.

[MenuItem("CBX/Test")]
public static void Test()
{
    // outputs "Assets/Rules.xml" if "Assets/Rules.xml" file does not already exist.
    // if "Assets/Rules.xml" already exists it outputs "Assets/Rules 1.xml"  
    Debug.Log(AssetDatabase.GenerateUniqueAssetPath("Assets/Rules.xml"));

    // expects path to start with "Assets/" & outputs a console error in the console "pathName.find("assets/") == 0"  
    // then outputs "Rules.xml" 
    Debug.Log(AssetDatabase.GenerateUniqueAssetPath("Rules.xml")); 
}