title: android.support.v7 Toolbar & DrawerLayout- how to change Hamburger icon
body: <p>My application uses ActionBarActivity and DrawerLayout and etc.
  i want to change the ActionBarDrawerToggle icon to be custom drawable.</p>
  
  <p>in my code i use android.support.v7.widget.Toolbar as SupportActionBar</p>
  
  <p>this is my code:</p>
  
  <pre><code> toolbar.setNavigationIcon(R.drawable.lifeline_shield);
   setSupportActionBar(toolbar);
   ActionBar actionbar = getSupportActionBar();
   actionbar.setDisplayHomeAsUpEnabled(true);
   actionbar.setDisplayShowTitleEnabled(false);
  
  mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, toolbar, R.string.somestring1, R.string.somestring2) ....
  </code></pre>
  
  <p>but still i see the Hamburger icon, so i have my own icon for opening the drawer. How can I solve this? without using deprecated api</p>