Q:

How to import other projects to use in my code ( Color picker )

I'm facing kinda embarrasing problem and for past 16hours I have trouble importing other projects into my project and use other classes in my project.
So I have some app which I have found that would be great to have some color picker. From searching google / stackoverflow I found that this color picker suits me, because it's also a preference.
LINK
So I've downloaded this big guy and try to import it into my project (Right button click on my project -> PROPERTIES -> JAVA BUILD PATH -> LIBRARIES -> ADD EXTERNAL CLASS FOLDER. I chose project I've downloaded earlier. It seems it worked because I can import classes into my project. See screenshot below:

However, in project's documentation it says: 
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 -->
/>

I've copied this code in my layout XML but i get following error in eclipse:
The following classes could not be found:
- net.margaritov.preference.colorpicker.ColorPickerPreference (Fix Build Path, Edit XML, Create Class)
What could be wrong? Did I messed up while importing? Why is not working? 

A:

You need that project as library just import that project go to Project->Properties->Android
Now in this select is library checked this option now that project rebuild as library.
Now in your project go to Project->properties->android
Click on Add button add library. It will open list of available library project which was imported by you. So select that it will added as library in your project

