相关疑难解决方法(0)

我正在努力实现这样的目标https://material.google.com/components/bottom-navigation.html#bottom-navigation-behavior

但是回收器视图隐藏在工具栏下方,并且对BottomNavigationView没有任何影响

以下是我的代码

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context=".MainActivity">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/app_bar_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">


        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:layout_scrollFlags="scroll|enterAlways"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />
    </android.support.design.widget.AppBarLayout>


    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">


        <android.support.design.widget.BottomNavigationView
            android:id="@+id/nm_bottom"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:background="@color/colorPrimaryDark"
            android:foregroundTint="@color/colorAccent"
            app:itemIconTint="@android:color/white"
            app:itemTextColor="@android:color/white"
            app:menu="@menu/nav_menu" />

        <android.support.v7.widget.RecyclerView
            android:id="@+id/rv"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_above="@id/nm_bottom"
            app:layout_behavior="@string/appbar_scrolling_view_behavior" />
    </RelativeLayout>

</android.support.design.widget.CoordinatorLayout>

item.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:padding="4dp">

    <android.support.v7.widget.CardView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:cardElevation="2dp">

        <RelativeLayout
            android:layout_width="fill_parent"
            android:layout_height="?android:attr/listPreferredItemHeight"
            android:padding="4dp">

            <ImageView
                android:id="@+id/icon"
                android:layout_width="wrap_content"
                android:layout_height="fill_parent"
                android:layout_alignParentBottom="true"
                android:layout_alignParentTop="true"
                android:layout_marginRight="6dip"
                android:contentDescription="TODO"
                android:src="@drawable/ic_storage" />

            <TextView …