实现fab随RecyclerView滑动隐藏显示，增加添加联系人页面，实现联系人拖动

app/src/main/res/layout/activity_contact_edit.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    tools:context=".activity.contact.edit.ContactEditActivity">
+
+    <data>
+        <variable
+            name="click"
+            type="com.ttstd.dialer.activity.contact.edit.ContactEditActivity.BtnClick" />
+    </data>
+
+    <androidx.constraintlayout.widget.ConstraintLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent">
+
+    </androidx.constraintlayout.widget.ConstraintLayout>
+</layout>