清理代码与更新界面

app/src/main/res/menu/book_source.xml

@@ -110,25 +110,21 @@
 
     <item
         android:id="@+id/menu_add_book_source"
-        android:icon="@drawable/ic_add"
         android:title="@string/add_book_source"
         app:showAsAction="never" />
 
     <item
         android:id="@+id/menu_import_local"
-        android:icon="@drawable/ic_import"
         android:title="@string/import_local"
         app:showAsAction="never" />
 
     <item
         android:id="@+id/menu_import_onLine"
-        android:icon="@drawable/ic_import"
         android:title="@string/import_on_line"
         app:showAsAction="never" />
 
     <item
         android:id="@+id/menu_import_qr"
-        android:icon="@drawable/ic_import"
         android:title="@string/import_by_qr_code"
         app:showAsAction="never" />
 
@@ -140,7 +136,6 @@
 
     <item
         android:id="@+id/menu_help"
-        android:icon="@drawable/ic_help"
         android:title="@string/help"
         app:showAsAction="never" />