Better BottomNavigationView

Trying to fix the biggest let down view in the Android design lib.
Everything wrong with BottomNavigationView.
This contains fixes for missing save state, accessibility and the colorful transition on tab change.

Basic usage

The view is written in Kotlin, but you can safely use it in your trusty old Java project if you are willing to import the Kotlin Standard library. See the example.

Basic Sample Usage.
Just like your regular BottomNavigationView you can inflate your custom menu.

<be.rijckaert.tim.library.BetterBottomBar
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/colorAccent"
        android:layout_alignParentBottom="true"
        android:layout_gravity="bottom"
        app:itemIconTint="@color/white"
        app:itemTextColor="@color/white"
        app:menu="@menu/bottom_navigation_main"/>

Text Colors And Icon Drawable

You can alter the text colors for each tab with the help of the app:XXXXTabTextColors.
For example for the first tab you should use app:firstTabTextColors.
just provide your custom ColorStateList

See the sample if you need more explanation

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:color="@color/textColorPrimary"
        android:state_checked="true"/>
    <item
        android:color="@color/textColorPrimaryUnselected"
        android:state_checked="false"/>
</selector>

Same for the icon drawable just use the app:XXXTabIconColors

Tab Change Listener

In order to receive tab change events you should attach a betterBottomBarClickListener.

betterBottomBar.betterBottomBarClickListener = { betterBottomBar, menuItem ->
    //get state
}

Save State

On rotation all the correct color are still applied to your view. You can also access the selectedTab index via code.

final BetterBottomBar betterBottomBar = (BetterBottomBar) findViewById(R.id.bottom_navigation);
betterBottomBar.getSelectedTab();

Color Animation

You can change the default colors with the app:colors attribute.
Make sure to reference an IntArray of colors

When no color array has been added, no animation will happen.

<be.rijckaert.tim.library.BetterBottomBar
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/colorAccent"
        android:layout_alignParentBottom="true"
        android:layout_gravity="bottom"
        app:itemIconTint="@color/white"
        app:itemTextColor="@color/white"
        app:colors="@array/bottom_bar_colors"
        app:menu="@menu/bottom_navigation_main"/>

@array/bottom_bar_colors

<array name="bottom_bar_colors">
    <item>@color/colorPrimary</item>
    <item>@color/someReddishColor</item>
    <item>@color/blackAsYourHeart</item>
</array>

###Accessibility Support

You can add accessibility to your BottomNavigationView by adding the app:contentDescriptionTitles attribute whichs refs to a StringArray.
If you forget to do this. The view will use reflection to look for your titles.
Don't be a dick just provide them.

<be.rijckaert.tim.library.BetterBottomBar
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/colorAccent"
        android:layout_alignParentBottom="true"
        android:layout_gravity="bottom"
        app:itemIconTint="@color/white"
        app:itemTextColor="@color/white"
        app:contentDescriptionTitles="@array/better_bottom_bar_accessibility_title"
        app:menu="@menu/bottom_navigation_main"/>

string.xml

<array name="better_bottom_bar_accessibility_title">
    <item>@string/news_title</item>
    <item>@string/video_title</item>
    <item>@string/discover_title</item>
</array>

At the moment it only supports:

• English
• Dutch

Feel free to submit PR for more language support