找不到以下类 - XML呈现错误

Question

我尝试预览我的activity_main.xml文件，但它给出了错误说＆＃34;无法找到以下课程＆＃34;

  The following classes could not be found:

- com.makeuprewardz.app.ui.view.BottomBar  (Fix Build Path, Edit XML, Create Class)

Tip: Try to build the project.

Tip: Try to refresh the layout.

我试图添加课程，现在它说＆＃34;它已经包含名为BottomBar的类。

这是我的activity_main.xml文件

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:fancy="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/transparent"
android:orientation="vertical">

<FrameLayout
    android:id="@+id/fl_container"
    android:layout_marginBottom="@dimen/bottombar_height"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

<com.makeuprewardz.app.ui.view.BottomBar
    android:id="@+id/bottomBar"
    android:layout_width="match_parent"
    android:layout_height="@dimen/bottombar_height"
    android:layout_gravity="bottom"/>

<ImageView
    android:layout_width="match_parent"
    android:background="@drawable/actionbar_shadow_up"
    android:layout_gravity="bottom"
    android:layout_marginBottom="@dimen/bottombar_height"
    android:layout_height="wrap_content"
    tools:ignore="ContentDescription" />