OK guys, I am done with it. I have been googling for last 2 days but I can't find the exact solution. Everyone is talking about configChanges and all those cliche things which do not seem to work in my case .
I have a login screen which consists of 2 EditTexts. Now this login screen has different layout for both Portrait and Landscape orientation . So I had to create one login.xml in layout folder and another login.xml in layout-land folder. And to support orientation changes I overrid onConfigurationChanged() method in LoginActivity class. In this method I call setContentView(R.layout.login) method so that appropriate login.xml is set as layout fro every orientation.
After all this I defined following in my manifest file as well:
android:configChanges="orientation|keyboardHidden"
But still I am facing the famous old problem. If there is any text in the Edittext and the device is rotated, that text is lost. I don't want to lose that text. Is it possible or not? I have read that we can do it using onSaveInstanceState(Bundle savedInstanceState) method and I have even tried that too but it din't work for me. Please help. Thanks in advance.