Open navigation drawer when application opens

MainActivty.java

public class MainActivity extends Activity {

    // Delay in millisec.
    private static final int DRAWER_DELAY = 200;
    // Member varaible for navigation drawer.
    private DrawerLayout mNavigationDrawerLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // Get the navigation drawer and assign to member variable.
        mNavigationDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
        // Set handler with delay.
        new Handler().postDelayed(openDrawerRunnable(), DRAWER_DELAY);
    }

    // Threaded method for opening navigation drawer.
    private Runnable openDrawerRunnable() {
        return new Runnable() {

            @Override
            public void run() {
                mNavigationDrawerLayout.openDrawer(Gravity.LEFT);
                // or
                // mNavigationDrawerLayout.openDrawer(Gravity.START);
            }
        };
    }
}