I want to implement colored BottomNavigationView with elevation (current design lib version 25.2.0, test device 7.1.2). Some code for start:
<android.support.design.widget.BottomNavigationView
android:id="@+id/bottom_navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_gravity="bottom"
android:elevation="8dp"
app:elevation="8dp"
app:menu="@menu/bottom_navigation" />
elevation (shadow) is not drawn, because there is no background. and there is known issue that this background must be white... ok, so I'm adding this line
android:background="@android:color/white"
but I wanted to set some color for background and white icons and text... with below lines
app:itemIconTint="@color/white"
app:itemTextColor="@color/white"
whole bar is solid white, including content, obviusly... so if background must be white also then lets change every item background with
app:itemBackground="@drawable/bottom_navigation_item_background"
and for drawable/
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true" android:drawable="@color/mycolor_dark"/>
<item android:drawable="@color/mycolor"/>
</selector>
for drawable-v21/ (ripple)
<?xml version="1.0" encoding="utf-8"?>
<ripple xmlns:android="http://schemas.android.com/apk/res/android"
android:color="@android:color/white">
<item android:drawable="@color/mycolor"/>
</ripple>
and now we have colored items and... no elevation again! and it will work when mycolor will be white (elevation shown/drawn)... so when I want elevation for BottomNavigationView both background and itemBackground must be white...
interesting part (proof of issue?) - lets check elevation with only this selector:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true" android:drawable="@android:color/white"/>
<item android:drawable="@color/mycolor"/>
</selector>
bar is drawn without elevation at all, but when I press any menu item then its background change to white and... there is elevation above this item, ONLY this item!
when I remove <item android:drawable="@color/mycolor"/> line from drawable-v21/ XML file (or set mycolor to white), then elevation is shown. ripple color have no impact, it might be white or any other (working).
the question is: how to style BottomNavigationView with custom color for background keeping elevation working?
