This one is almost silly, but since I haven't posted in a while...
Android doesn't let you change the account color for exchange calendars. Instead it picks a color at random when the account is first created. Awesome. Well, it's not *too* hard to change without a dedicated app. Let's get started...
First I need to open the android shell (
adb shell) and find the calendar database. Mine was at
Next, let's look at the database...
$ sqlite3 calendar.db
sqlite> select _id, account_name, calendar_displayName, calendar_color from Calendars;
So that last column is the color, in the format described here. Which explains why all of the numbers are negative - the first byte is always 0xFF (fully opaque.) Too bad I can't force it to be interpreted as hex.
I'm not putting too much thought into this, so the easiest thing I can think of to make the number easy to interpret as a hex color code: Use Python's
struct module to convert numbers to byte representation and vice versa...
$ python >>> '%08x' % struct.unpack('>I',struct.pack('>i',-15574510)) 'ff125a12'
Good - that's what I expected. Quick explanation of the above - I'm basically telling python to convert a signed number to a byte array (pack,) then "unpacking" that byte array as an unsigned number. So I can do the inverse to convert a hex value from a color wheel app back to a signed integer.
So pick a color... I want 0xffbb0088. To convert that back to a signed number, I do t the inverse of the above in python...
>>> struct.unpack('>i',struct.pack('>I',0xffbb0088)) -4521848
... and there is my number. Update the account via sqlite...
sqlite> update Calendars set calendar_color=-4521848 where _id=2;
Bam. Not as easy as it should be, but not terribly difficult either.