content: package example.easy.animations;
  
  import android.os.Bundle;
  import android.support.annotation.NonNull;
  import android.support.design.widget.NavigationView;
  import android.support.v4.view.GravityCompat;
  import android.support.v4.widget.DrawerLayout;
  import android.support.v7.app.ActionBarDrawerToggle;
  import android.support.v7.app.AppCompatActivity;
  import android.support.v7.widget.Toolbar;
  import android.view.Menu;
  import android.view.MenuItem;
  
  public class MainActivity extends AppCompatActivity
      implements NavigationView.OnNavigationItemSelectedListener {
  
    @Override protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
      setSupportActionBar(toolbar);
  
      DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
      ActionBarDrawerToggle toggle =
          new ActionBarDrawerToggle(this, drawer, toolbar, R.string.navigation_drawer_open,
              R.string.navigation_drawer_close);
      //noinspection deprecation
      drawer.setDrawerListener(toggle);
      toggle.syncState();
  
      NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
      navigationView.setNavigationItemSelectedListener(this);
    }
  
    @Override public void onBackPressed() {
      DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
      if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
      } else {
        super.onBackPressed();
      }
    }
  
    @Override public boolean onCreateOptionsMenu(Menu menu) {
      // Inflate the menu; this adds items to the action bar if it is present.
      getMenuInflater().inflate(R.menu.main, menu);
      return true;
    }
  
    @Override public boolean onOptionsItemSelected(MenuItem item) {
      // Handle action bar item clicks here. The action bar will
      // automatically handle clicks on the Home/Up button, so long
      // as you specify a parent activity in AndroidManifest.xml.
      int id = item.getItemId();
  
      //noinspection SimplifiableIfStatement
      if (id == R.id.action_settings) {
        return true;
      }
  
      return super.onOptionsItemSelected(item);
    }
  
    @SuppressWarnings("StatementWithEmptyBody") @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
      // Handle navigation view item clicks here.
      int id = item.getItemId();
  
      if (id == R.id.nav_flip) {
        // Handle the flip action
      }
  
      DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
      drawer.closeDrawer(GravityCompat.START);
      return true;
    }
  }
  