Come centrare titolo esteso in un CollapsingToolbarLayout

Question

voglio centrare il titolo della barra degli strumenti quando il layout è espansa, questo è il mio codice:

<?xml version="1.0" encoding="utf-8"?> 
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:app="http://schemas.android.com/apk/res-auto" 
android:id="@+id/main_content" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:fitsSystemWindows="true"> 
<android.support.design.widget.AppBarLayout 
    android:layout_height="256dp" 
    android:layout_width="match_parent" 
    app:contentScrim="?attr/colorPrimary" 
    android:fitsSystemWindows="true" 
    app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"> 
    <android.support.design.widget.CollapsingToolbarLayout 
     android:id="@+id/collapsing_toolbar" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     app:layout_scrollFlags="scroll|exitUntilCollapsed" 
     android:fitsSystemWindows="true" 
     app:contentScrim="?attr/colorPrimary" 
     app:expandedTitleMarginStart="48dp" 
     app:expandedTitleMarginBottom="60dp"> 
     <ImageView 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      android:scaleType="centerCrop" 
      android:fitsSystemWindows="true" 
      app:layout_collapseMode="parallax"/> 
     <android.support.v7.widget.Toolbar 
      android:id="@+id/toolbar" 
      android:layout_height="?attr/actionBarSize" 
      android:layout_width="match_parent" 
      app:layout_collapseMode="pin" 
      app:popupTheme="@style/ThemeOverlay.AppCompat.Light" /> 
    </android.support.design.widget.CollapsingToolbarLayout> 
</android.support.design.widget.AppBarLayout> 
<android.support.v4.widget.NestedScrollView 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    app:layout_behavior="@string/appbar_scrolling_view_behavior"> 
</android.support.v4.widget.NestedScrollView> 

Answer 1

Provate ad aggiungere la expandedTitleGravity al CollapsingToolbarLayout come attributo app:

app:expandedTitleGravity="center_horizontal" 

Esempio:

<android.support.design.widget.CollapsingToolbarLayout 
     android:id="@+id/collapsing_toolbar" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:fitsSystemWindows="true" 
     app:contentScrim="@color/colorPrimary" 
     app:expandedTitleGravity="center_horizontal"    
     app:layout_scrollFlags="scroll|exitUntilCollapsed"> 

Answer 2

si può semplicemente modificare i valori di questi due attributi

app:expandedTitleMarginEnd="64dp" 
    app:expandedTitleMarginStart="48dp" 

in

<android.support.design.widget.CollapsingToolbarLayout 
    android:id="@+id/collapsing_toolbar" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    app:layout_scrollFlags="scroll|exitUntilCollapsed" 
    android:fitsSystemWindows="true" 
    app:contentScrim="?attr/colorPrimary"  
    app:expandedTitleMarginStart="48dp" 
    app:expandedTitleMarginEnd="64dp" 
    app:expandedTitleMarginBottom="60dp">