It happen when you make update build sdk version ,I resolved it by Searching layout_anchorGravity inside entire project in Android Studio ,using CTR+H shortcut,
it open file /users/{user}/.android/build.cache/~/output/res/values/values.xml
I delete this line from file
<declare-styleable name="CoordinatorLayout_LayoutParams"><attr name="android:layout_gravity"/><attr format="string" name="layout_behavior"/><attr format="reference" name="layout_anchor"/><attr format="integer" name="layout_keyline"/><attr name="layout_anchorGravity"><flag name="top" value="0x30"/><flag name="bottom" value="0x50"/><flag name="left" value="0x03"/><flag name="right" value="0x05"/><flag name="center_vertical" value="0x10"/><flag name="fill_vertical" value="0x70"/><flag name="center_horizontal" value="0x01"/><flag name="fill_horizontal" value="0x07"/><flag name="center" value="0x11"/><flag name="fill" value="0x77"/><flag name="clip_vertical" value="0x80"/><flag name="clip_horizontal" value="0x08"/><flag name="start" value="0x00800003"/><flag name="end" value="0x00800005"/></attr></declare-styleable>
and then from onther java file I removed import android.support.v7.app.NotificationCompat;
I clean and build ,it build successfully