AppBarLayout 中ViewPage滑动

1、 AppBarLayout.OnOffsetChangedListener：
在你下拉刷新时候， 即 appBar下拉到0后即： verticalOffset == 0 时候，开始对指定页面刷新；否则不刷新。

public void onOffsetChanged (AppBarLayout appBarLayout, int verticalOffset) {
if (storeFragment == null || mZoneFragment == null)
return;
if (verticalOffset == 0) {
storeFragment.setCanRefresh (true);
mZoneFragment.setCanRefresh (true);
} else {
storeFragment.setCanRefresh (false);
mZoneFragment.setCanRefresh (false);
}

实现viewPage在滑动时候，AppBar自动隐藏，这里用到CoordinatorLayout能做什么？看http://blog.csdn.net/huachao1001/article/details/51554608

2、<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"
android:orientation="vertical">

<android.support.design.widget.AppBarLayout
    android:id="@+id/app_bar_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/blue"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        app:contentInsetStart="0dp"
        app:layout_scrollFlags="scroll|enterAlways"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light">

     
    <android.support.design.widget.TabLayout
        android:id="@+id/tb_risk"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/white"
        app:tabGravity="fill"
        app:tabIndicatorColor="@color/blue"
        app:tabMode="fixed"
        app:tabSelectedTextColor="@color/blue"
        app:tabTextColor="@color/light_gray"/>
</android.support.design.widget.AppBarLayout>

<android.support.v4.view.ViewPager
    android:id="@+id/vp_risk"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

</android.support.design.widget.CoordinatorLayout>