Android activity restart

Hey guys, i am making an android application where i want to show a dialog box about legal agreement everytime the application starts, i have a public method showalert(<>); which shows an alertdialog by building a dialog with alertbuilder. I added a call to showalert() method on the onCreate() method of the main activity to show it, but whenever the user rotates the screen, he g开发者_如何学运维ets the dialog everytime. The activity restarts itself when the phone is rotated. I tried adding android:configChanges="keyboardHidden|orientation" to my manifest but that doesnt help on this case. Also can i know how to register a new application class on manifest file. I am trying to create an application class and put the code to show dialog on the new class's oncreate method. But i am not being able to load the class when the app starts.

I also checked Activity restart on rotation Android but i dont seem to get a thing. I am pretty much a newbie to android programming, could someone simplify that for me?

Any help would be appreciated. :)

you could maybe look at the onRetainNonConfigurationInstance() activity method, which is called just before destroying and re-creating the activity on screen orientation change.

it allows you to retain an object that could for instance contain a test variable to know if your legal thing was already shown or not.. example :

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    final String test = (String) getLastNonConfigurationInstance();
    if (!("textAlreadyShown").equals(test)) {
        //here : show your dialog
    }
}

@Override
public String onRetainNonConfigurationInstance() {
    return "textAlreadyShown";
}   

Set the main activity to an activity that just shows the legal notice, when it is accepted/cleared, show a second activity ( which is currently the main activity )?