Display the fragment as the main content of activity

SomeActivity.java

public class SettingsActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Display the fragment as the main content.
       getFragmentManager().beginTransaction()
               .replace(android.R.id.content, new SomeFragment())
               .commit();
    }