title: CollapsingToolbarLayout center TextView in Toolbar
body: <p>I want toolbar_title layout center in toolbar, but itlooks like there is some margin on left, if I remove CollapsingToolbarLayout it is ok.
  Inorder to center toolbar_title text I set toolbar_title's margin right manualy in code, but the only after the fragment resumed I toolbar_title.getX() can get the correct value, so I postDelayed 50 ms to do this.</p>
  
  <p>now ther is the question:
  how to center toolbar_title in CoordinatorLayout on a better way? </p>
  
  <pre><code>&lt;android.support.design.widget.CoordinatorLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  xmlns:tools="http://schemas.android.com/tools"&gt;
  
  &lt;android.support.design.widget.AppBarLayout
      android:layout_width="match_parent"
      android:layout_height="wrap_content"&gt;
  
      &lt;android.support.design.widget.CollapsingToolbarLayout
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          app:expandedTitleMarginStart="?attr/actionBarSize"
          app:layout_scrollFlags="scroll|exitUntilCollapsed"&gt;
  
          &lt;LinearLayout
              android:id="@+id/layout_header"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:background="#f5f5f5"
              android:orientation="vertical"
              app:layout_collapseMode="parallax"&gt;
          &lt;/LinearLayout&gt;
  
          &lt;android.support.v7.widget.Toolbar
              android:id="@+id/toolbar"
              android:layout_width="match_parent"
              android:layout_height="?attr/actionBarSize"
              android:background="?attr/colorPrimary"
              android:theme="@style/AppTheme.ToolBar"
              app:layout_collapseMode="pin"
              app:popupTheme="@style/AppTheme.PopupOverlay"&gt;
  
              &lt;TextView
                  android:id="@+id/toolbar_title"
                  style="@style/TextAppearance.AppCompat.Widget.ActionBar.Title"
                  android:layout_width="match_parent"
                  android:layout_height="wrap_content"
                  android:gravity="center"
                  android:textColor="@android:color/white"
                  android:textSize="18sp"
                  tools:text="title"/&gt;
  
          &lt;/android.support.v7.widget.Toolbar&gt;
      &lt;/android.support.design.widget.CollapsingToolbarLayout&gt;
  &lt;/android.support.design.widget.AppBarLayout&gt;
  
  &lt;android.support.v7.widget.RecyclerView
      android:id="@+id/swipe_container"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      app:layout_behavior="@string/appbar_scrolling_view_behavior"/&gt;
  </code></pre>
  
  <p></p>