You can add data with the Intent to your ColorPicker activity in the following manner:
Intent intent = new Intent(this, ColorPickerActivity.class);
intent.putExtra("UNIQUE_KEY_FOR_THIS_COLOR_INFORMATION", colorIndex);
and retrieve it at your receiving side:
getIntent().getIntExtra("UNIQUE_KEY_FOR_THIS_COLOR_INFORMATION", -1);
where -1 is the default data if no value for that key is found.
Android has a pretty detailed documentation of Intents, which you should go through: http://developer.android.com/reference/android/content/Intent.html