在ConstraintLayout xml中取消设置属性

我有一个默认样式 ConstraintLayout 行为现在我想重置 layout_constraintTop_toTopOf 属性以获取正确的约束 layout_constraintTop_toBottomOf 。如何删除 layout\u constraintTop\u toTopOf布局 从视图中?

样式。xml:

<style name="ConstraintDefault">
    <item name="android:layout_width">0dp</item>
    <item name="android:layout_height">0dp</item>
    <item name="layout_constraintBottom_toBottomOf">parent</item>
    <item name="layout_constraintEnd_toEndOf">parent</item>
    <item name="layout_constraintStart_toStartOf">parent</item>
    <item name="layout_constraintTop_toTopOf">parent</item>
</style>

main\u布局。xml:

<android.support.constraint.ConstraintLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <include
        android:id="@+id/include_toolbar"
        layout="@layout/layout_toolbar" />

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rvDummy"
        style="@style/ConstraintDefault"
        app:layout_constraintTop_toBottomOf="@id/include_toolbar" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        style="@style/Fab"
        app:srcCompat="@drawable/ic_add" />

</android.support.constraint.ConstraintLayout>

结果: RecyclerView 重叠 Toolbar 因为 app:layout_constraintTop_toTopOf="parent"