RecyclerView一个view居中

xml布局

 <android.support.v7.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:id="@+id/rv_wu_xian_data"
android:layout_height="match_parent">
</android.support.v7.widget.RecyclerView>

GridLayoutManager

   GridLayoutManager manager = new GridLayoutManager (getActivity(),1);

子Item

    <LinearLayout       
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/rl_zhiye_hos_root_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:orientation="horizontal"
android:visibility="visible">

   <ImageView
    android:id="@+id/iv_da_tou"
    android:layout_width="@dimen/xct_space_value_x180"
    android:layout_height="@dimen/xct_space_value_x180"
    android:layout_margin="@dimen/xct_space_value_x10"
    android:scaleType="centerCrop"
    android:src="@drawable/icon_xiaonezha" />
   </LinearLayout>