I\'m developing an Android app using GreenDroid. The application is just for testing atm, so it all it contains is an ActionBar with a refresh button, three tabs, and an act
If you don't want the other Activity instantiated, then that's not the place for this method. If it's shared functionality between more than one Activity, why not create a base class for your activities that derives from Activity.
public class ActivityBase extends Activity
{
public void showToast()
{
...
Then your activities derive from this
public class MyActivity extends ActivityBase
{
public void someMethod()
{
showToast();