单击 FAB 上的 Alpha 背景

I'm using the library https://github.com/futuresimple/android-floating-action-button https://github.com/futuresimple/android-floating-action-button to create the fab buttons that works pretty well. I tried several libraries but none use the effect used in most application with a fab (or Google apps like keep, inbox) that when the fab is clicked the background of entire application becames semi-transparent white or black, it depends. I can't find any way to do it. Is it possible have an example or something like that to do this kind of effect? You can see what i mean in this image:

半黑背景

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <RelativeLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <include
            android:id="@+id/toolbar"
            layout="@layout/toolbar" />
    </RelativeLayout>

    <RelativeLayout
        android:id="@+id/semi_white_bg"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/white_semi_transparent"
        android:visibility="gone" >
    </RelativeLayout>

    <RelativeLayout
        android:id="@+id/listFrame"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@+id/content_frame"
        android:visibility="gone" >

        <TextView
            android:id="@+id/status"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/cabinet_color"
            android:fontFamily="sans-serif"
            android:gravity="center_vertical"
            android:paddingBottom="8dp"
            android:paddingLeft="16dp"
            android:paddingRight="16dp"
            android:paddingTop="8dp"
            android:textColor="#fff"
            android:textSize="17sp"
            android:visibility="gone" />

        <android.support.v7.widget.RecyclerView
            android:id="@android:id/list"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_below="@+id/status"
            android:clipToPadding="false"
            android:scrollbars="vertical" />

        <LinearLayout
            android:id="@android:id/empty"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:orientation="vertical" >

            <ImageView
                android:id="@+id/emptyImage"
                android:layout_width="96dp"
                android:layout_height="96dp"
                android:layout_gravity="center_horizontal"
                android:layout_marginBottom="16dp"
                android:scaleType="fitXY"
                android:src="?empty_image" />

            <TextView
                android:id="@+id/emptyText"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center_horizontal"
                android:layout_marginLeft="16dp"
                android:layout_marginRight="16dp"
                android:fontFamily="sans-serif-light"
                android:gravity="center"
                android:lineSpacingMultiplier="1.4"
                android:paddingBottom="16dp"
                android:text="@string/no_files"
                android:textColor="?empty_text"
                android:textSize="22sp" />
        </LinearLayout>
    </RelativeLayout>

    <ProgressBar
        android:id="@android:id/progress"
        style="?android:progressBarStyle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:indeterminateOnly="true" />

</RelativeLayout>

这是我的layout.xml，但似乎根本无法按照我想要的方式工作。似乎没有重叠整个视图，而只是为它想要的颜色着色。

我发现这是我认为最简单的解决方案，而且效果很好：

fam.setOnFloatingActionsMenuUpdateListener(new FloatingActionsMenu.OnFloatingActionsMenuUpdateListener() {
        @Override
        public void onMenuExpanded() {
            dimmedBackground.setVisibility(View.VISIBLE);
        }

        @Override
        public void onMenuCollapsed() {
            dimmedBackground.setVisibility(View.GONE);
        }
    });