效果
思路
获取整个BottomNavigationView菜单，再根据下标获取某一个子菜单tab，然后给这个tab添加我们自定义的view，可以是数字也可以是文字。
代码
/** * 给BottomNavigationView 设置Badge 小红点 * * BottomNavigationMenuView中的每一个Tab是一个FrameLayout，所以可以在上面随意添加View、这样就可以实现角标了 */ private fun setBadge() { //获取底部菜单view val menuView = bottom_navigation.getChildAt(0) as BottomNavigationMenuView //获取第2个itemView val itemView = menuView.getChildAt(1) as BottomNavigationItemView //引入badgeView val badgeView = LayoutInflater.from(this).inflate(R.layout.layout_badge_view, menuView, false) //把badgeView添加到itemView中 itemView.addView(badgeView) //获取子view并设置显示数目 val count = badgeView.findViewById<TextView>(R.id.tv_badge) count.text = "2" //不显示则隐藏 //count.visibility=View.GONE }
layout_badge_view就是自定义的一个layout
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <TextView android:id="@+id/tv_badge" android:layout_width="@dimen/dp_18" android:layout_height="@dimen/dp_18" android:layout_gravity="center" android:layout_marginLeft="@dimen/dp_10" android:layout_marginTop="@dimen/dp_2" android:background="@drawable/shape_oval_primary" android:gravity="center" android:includeFontPadding="false" android:text="1" android:textColor="@color/white" /> </LinearLayout>
shape_oval_primary是一个背景为主题色的圆
<?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval" android:useLevel="false"> <solid android:color="@color/colorPrimary" /> <stroke android:width="0dp" android:color="@color/white" /> <size android:width="10dp" android:height="10dp" /> </shape>
