title: How to center toolbar back button?
body: <p>I'm having a problem trying to center the back button on the support toolbar.
  I'm using it inside an ActionBarActivity.</p>
  
  <pre><code>&lt;android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:toolbar="http://schemas.android.com/apk/res-auto"
      android:id="@+id/toolbar"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:background="?attr/colorPrimary"
      android:minHeight="?attr/actionBarSize"
      toolbar:popupTheme="@style/ThemeOverlay.AppCompat.Light"
      toolbar:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" /&gt;
  </code></pre>
  
  <p>And set the up navigation inside the Activity's <code>onCreate()</code> like this:</p>
  
  <pre><code>Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
  setSupportActionBar(toolbar);
  
  getSupportActionBar().setTitle(R.string.title_activity_scanner);
  getSupportActionBar().setDisplayHomeAsUpEnabled(true);
  </code></pre>
  
  <p>However, what I'm getting is this:</p>
  
  <p><img src="https://i.stack.imgur.com/rSwJR.png" width="300"></p>
  
  <p>As you can see the back button is misplaced</p>
  
  <p>Edit:
  The problem seems to lie in a custom value for <code>?attr/actionBarSize</code> set to 40dp, however, it turns out now, that it's the title that is misplaced instead.</p>