Generally used classes by Daniel Nilsson. ColorPickerPreference class by Sergey Margaritov. Packed by Sergey Margaritov.
- Color Area
 - Hue Slider
 - Alpha Slider (disabled by default)
 - Old & New Color
 - Color Preview in Preferences List
 
Tested with APIv7, but maybe will work with early versions
You can see some tests inside
<net.margaritov.preference.colorpicker.ColorPickerPreference
    android:key="color1"
    android:title="@string/color1_title"
    android:summary="@string/color1_summary"
    android:defaultValue="@color/pumpkin_orange"    <!-- integer resources are also accepted -->
    alphaSlider="true"                              <!-- enable alpha slider via XML -->
/>
To enable Alpha Slider in your code use function:
setAlphaSliderEnabled(boolean enable)

