Adding a border below Toolbar android

Issue

I'm trying to add a border that would look like this: https://imgur.com/a/r8rHGQl

My toolbar.xml:

<android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/toolbar_main"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/colorPrimary"
android:elevation="1dp"
app:theme="@style/AppTheme"
app:titleTextAppearance="@style/TitleText"
app:titleTextColor="@color/colorPrimaryText"

>
</android.support.v7.widget.Toolbar>

In my java code I do : toolbar = findViewById(R.id.toolbar); setSupportActionBar(toolbar); and inflating the menu.

If I try to nest the toolbar in relative/linear/constrains layout and add a View at the bottom I get the "android.widget.LinearLayout cannot be cast to android.support.v7.widget.Toolbar" error

Also tried to <include a layout with a View inside of it, but then the line appears in the middle of my toolbar and my title disappears.

Also including my menu.xml:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<item
android:id="@+id/item1"
android:icon="@drawable/main_btn_info"
android:title="Item 1"
app:showAsAction="always"/>
</menu>

Solution

1. Create toolbar inside Linear Layout with a view

   <LinearLayout 
   xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:app="http://schemas.android.com/apk/res-auto"
   android:orientation="vertical"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   
      <android.support.v7.widget.Toolbar    
      android:id="@+id/toolbar_main"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:background="@color/colorPrimary"
      android:elevation="1dp"
      app:theme="@style/AppTheme"
      app:titleTextAppearance="@style/TitleText"
      app:titleTextColor="@color/colorPrimaryText"/>
   
      <View 
      android:background="your border color"
      android:layout_width="match_parent"
      android:layout_height="2dp" />
   
   </LinearLayout>
   

2. Include this in all your layouts.

3. Then find toolbar in activity using toolbar id instead of xml name

   toolbar = findViewById(R.id.toolbar_main); 
   setSupportActionBar(toolbar);
   

Answered By - Deven