The Bottom Navigation View has been in the material design guidelines for some time, but it hasn’t been easy for us to implement it into our apps. Some applications have built their own solutions, whilst others have relied on third-party open-source libraries to get the job done. Now the design support library is seeing the addition of this bottom navigation bar, let’s take a dive into how we can use it and modify!
compile 'com.android.support:appcompat-v7:26.+'
compile 'com.android.support:design:26.+'
compile 'com.android.support:support-v4:26.+'layout/activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
tools:context="com.eti.nucleus.bottombarnavigationview.MainActivity">
<!-- Content Container -->
<android.support.design.widget.BottomNavigationView
android:id="@+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
app:itemBackground="@android:color/white"
app:itemIconTint="@color/tinting_selected_items"
app:itemTextColor="@color/tinting_selected_items"
app:menu="@menu/bottombar_items"/>
</RelativeLayout>You’ll notice that the widget has a couple of attributes set on it:
- app:itemBackground: The background color to be used for the bottom navigation menu
- app:itemIconTint: The tint to be used for the icons in the bottom navigation menu
- app:itemTextColor: The color to be used for the text in the bottom navigation menu
- app:menu: The menu resource to be used to display items in the bottom navigation menu
We can also set these values programatically by using the following methods:
- inflateMenu(int menuResource): Inflate a menu for the bottom navigation view using a menu resource identifier
- setItemBackgroundResource(int backgroundResource): The background to be used for the menu items.
- setItemTextColor(ColorStateList colorStateList): A ColorStateList used to color the text used for the menu items
- setItemIconTintList(ColorStateList colorStateList): A ColorStateList used to tint the icons used for the menu items
menu/bottombar_itens.xml
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item
android:id="@+id/menu_item1"
android:icon="@drawable/home"
android:title="@string/menu_item1"/>
<item
android:id="@+id/menu_item2"
android:icon="@drawable/search"
android:title="@string/menu_item2"/>
<item
android:id="@+id/menu_item3"
android:icon="@drawable/play"
android:title="@string/menu_item3"/>
<item
android:id="@+id/menu_item4"
android:icon="@drawable/favorite"
android:title="@string/menu_item4"/>
<item
android:id="@+id/menu_item5"
android:icon="@drawable/user"
android:title="@string/menu_item5"/>
</menu>It’s important to note that the maximum number of items we can display is 5.
To make the view handle these cases we only simply need to create a selector file for our enabled / disabled colors.
color/handling_states.xml
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item
android:color="@color/colorAccent"
android:state_checked="false"/>
<item
android:color="@color/colorPrimary"
android:state_checked="true"/>
</selector>Now we’ve implemented our menu we need to be able to react when it’s interacted with. We can use the BottomNavigationView setOnNavigationItemSelectedListener method to set a listener for menu item events:
MainActivity.kt
private lateinit var bottomNavigationView: BottomNavigationView
bottomNavigationView = findViewById(R.id.navigation)
supportFragmentManager.beginTransaction().replace(R.id.framelayout,Fragment3()).commit()
bottomNavigationView.selectedItemId = R.id.menu_item3
bottomNavigationView.setOnNavigationItemSelectedListener { item ->
var selectedFragment: Fragment? = null
when (item.itemId) {
R.id.menu_item1 -> selectedFragment = Fragment1()
R.id.menu_item2 -> selectedFragment = Fragment2()
R.id.menu_item3 -> selectedFragment = Fragment3()
R.id.menu_item4 -> selectedFragment = Fragment4()
R.id.menu_item5 -> selectedFragment = Fragment5()
}
val transaction = supportFragmentManager.beginTransaction()
transaction.replace(R.id.framelayout, selectedFragment)
transaction.commit()
true
}We created a file called BottomNavigationViewHelper.kt where all the features are implemented.
To remove the animation, simply call the disableShiftMode function by passing an instance of the bottomNavigationView per parameter:
MainActivity.kt
BottomNavigationViewHelper.disableShiftMode(bottomNavigationView)
To remove the text label, simply call the removeTextLabel function by passing an instance of the bottomNavigationView per parameter:
MainActivity.kt
BottomNavigationViewHelper.removeTextLabel(bottomNavigationView)
To modify size icon, simply call the sizeIcon function by passing as instance of the bottomNavigationView, an resource display metrics and a floating value that you want to change the icon:
MainActivity.kt
BottomNavigationViewHelper.sizeIcon(bottomNavigationView,resources.displayMetrics,28f)
To add a badge to the bottom bar the first step is to create a layout for it:
layout/badge.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/notifications.badge"
android:layout_width="wrap_content"
android:minWidth="20dp"
android:layout_height="wrap_content"
android:minHeight="20dp"
android:layout_gravity="top|center_horizontal"
android:layout_marginStart="14dp"
android:layout_marginTop="2dp"
android:background="@drawable/notification_badge"
android:gravity="center"
android:text="@string/notification_badge"
android:textColor="@android:color/white"
android:textSize="12sp" />
</FrameLayout>After, to add badge, simply call the addBadge function by passing as instance of the bottomNavigationView, an activity and a position value that you want to add your badge:
MainActivity.kt
BottomNavigationViewHelper.addBadge(bottomNavigationView,this,3)
Pull requests for new features, bug fixes, and suggestions are welcome!
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