Android Toolbar自定义标题标题居中的实例代码

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 xmlns:app="http://schemas.android.com/apk/res-auto">
 <android.support.v7.widget.Toolbar
  android:id="@+id/main_toolbar"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:minHeight="?attr/actionBarSize"
  android:background="@color/colorblue"
  app:contentInsetStart="0dp"
  android:layout_gravity="center"
  app:popupTheme="@style/AppTheme.PopupOverlay">
  <TextView
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:gravity="center"
   android:text="标题"
   android:textColor="@color/group_button_dialog_pressed_holo_light"
   android:textSize="22sp" />
 </android.support.v7.widget.Toolbar>
.......

<resources>
 <!-- Base application theme. -->
 <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
  <!-- Customize your theme here. -->
  <item name="colorPrimary">@color/colorPrimary</item>
  <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
  <item name="colorAccent">@color/colorAccent</item>
  <item name="windowActionBar">false</item>
  <item name="android:windowActionBar">false</item>
  <item name="android:windowNoTitle">true</item>
  <item name="windowNoTitle">true</item>
 </style>

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  Toolbar mToolbar = (Toolbar) findViewById(R.id.main_toolbar);
  setSupportActionBar(mToolbar);
 }