Open Navigation Drawer at startup

Question

I'm fairly new to android programming and developed an app that has a Navigation Drawer implemented. Per Google guidelines, i'd like the NavDraw to start open but am unable to do this.

This is my onCreate (I guess this is where I should implement this feature, right?)

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActionBar().getThemedContext(), android.R.layout.simple_list_item_1, menuEntries);

    final DrawerLayout drawer = (DrawerLayout)findViewById(R.id.drawer_layout);
    final ListView navList = (ListView) findViewById(R.id.drawer);

    getActionBar().setDisplayHomeAsUpEnabled(true);
    getActionBar().setHomeButtonEnabled(true);

    drawerToggle = new ActionBarDrawerToggle(
            this,
            drawer,
            R.drawable.ic_drawer,
            R.string.drawer_open,
            R.string.drawer_close
    ) 

(...)

Answer 1

使用drawer.openDrawer(Gravity.LEFT);

Answer 2

You can use

 drawer.openDrawer(Gravity.LEFT);

or

drawer.openDrawer(Gravity.RIGHT`);