How to Install Android SDK
When you launch Eclipse, the Eclipse IDE looks on the hard drive for the prewritten, reusable Android code files. (After all, Eclipse uses these files to help you write and run Android apps.) If Eclipse has trouble finding these files, you see a nasty-looking Could Not Find SDK Folder message. To tell Eclipse where to install the Android SDK files, follow these steps:
In Windows, in the Eclipse main menu, choose Window→Preferences. On the Mac, in the Eclipse main menu, choose Eclipse→Preferences.
The Eclipse Preferences dialog box opens.
In the tree list on the left side of the Preferences dialog box, select Android.
Don’t expand the Android branch of the tree. Simply click the word Android.
The SDK Location field appears in the main body of the Preferences dialog box, as shown in the figure.
Click the Browse button and (of course) browse to the ANDROID_HOME directory.
Click Apply and OK, and all those good things to return to the main Eclipse workbench.
Look again at the figure and notice the text box in the window’s upper-left corner — the box containing the words type filter text. The text box is for filtering the names of Eclipse preferences. The figure displays only 11 preferences (such as General, Android, Ant, and C++). But this list of preferences expands to a tree with approximately 150 branches.
Each branch refers to its own set of choices in the main body of the Preferences window. If you want to see a bunch of Eclipse preferences related to font (for example), type font in the little text box. Eclipse then displays only branches of the tree containing the word font.