Contacts/app/src/main/res/layout/activity_dialpad.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/dialpad_holder"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentBottom="true"
    android:focusableInTouchMode="true">

    <com.simplemobiletools.commons.views.MyRecyclerView
        android:id="@+id/dialpad_list"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:clipToPadding="false"
        android:scrollbars="none"
        app:layoutManager="com.simplemobiletools.commons.views.MyLinearLayoutManager"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_input"
        app:layout_constraintTop_toTopOf="parent"/>

    <com.simplemobiletools.commons.views.FastScroller
        android:id="@+id/dialpad_fastscroller"
        android:layout_width="wrap_content"
        android:layout_height="0dp"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true"
        android:paddingStart="@dimen/normal_margin"
        android:paddingLeft="@dimen/normal_margin"
        app:layout_constraintBottom_toBottomOf="@+id/dialpad_list"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="@+id/dialpad_list">

        <include layout="@layout/fastscroller_handle_vertical"/>

    </com.simplemobiletools.commons.views.FastScroller>

    <TextView
        android:id="@+id/dialpad_divider"
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="@drawable/divider"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_input"/>

    <com.simplemobiletools.commons.views.MyEditText
        android:id="@+id/dialpad_input"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/activity_margin"
        android:gravity="center"
        android:inputType="phone"
        android:textCursorDrawable="@null"
        android:textSize="@dimen/dialpad_text_size"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_2"
        app:layout_constraintEnd_toStartOf="@+id/dialpad_clear_char"
        app:layout_constraintStart_toStartOf="parent"/>

    <ImageView
        android:id="@+id/dialpad_clear_char"
        android:layout_width="wrap_content"
        android:layout_height="0dp"
        android:layout_marginEnd="@dimen/activity_margin"
        android:background="?attr/selectableItemBackgroundBorderless"
        android:paddingStart="@dimen/activity_margin"
        android:paddingEnd="@dimen/activity_margin"
        android:src="@drawable/ic_backspace_vector"
        app:layout_constraintBottom_toBottomOf="@+id/dialpad_input"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="@+id/dialpad_input"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_1"
        style="@style/DialpadNumberStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/activity_margin"
        android:text="1"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_4"
        app:layout_constraintEnd_toStartOf="@+id/dialpad_2"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_2"
        style="@style/DialpadNumberStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="2"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_5"
        app:layout_constraintEnd_toStartOf="@+id/dialpad_3"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/dialpad_1"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_2_letters"
        style="@style/DialpadLetterStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="ABC"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_5"
        app:layout_constraintEnd_toStartOf="@+id/dialpad_3"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/dialpad_1"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_3"
        style="@style/DialpadNumberStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginRight="@dimen/activity_margin"
        android:text="3"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_6"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/dialpad_2"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_3_letters"
        style="@style/DialpadLetterStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginRight="@dimen/activity_margin"
        android:text="DEF"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_6"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/dialpad_2"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_4"
        style="@style/DialpadNumberStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/activity_margin"
        android:text="4"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_7"
        app:layout_constraintEnd_toStartOf="@+id/dialpad_5"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_4_letters"
        style="@style/DialpadLetterStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/activity_margin"
        android:text="GHI"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_7"
        app:layout_constraintEnd_toStartOf="@+id/dialpad_5"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_5"
        style="@style/DialpadNumberStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="5"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_8"
        app:layout_constraintEnd_toStartOf="@+id/dialpad_6"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/dialpad_4"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_5_letters"
        style="@style/DialpadLetterStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="JKL"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_8"
        app:layout_constraintEnd_toStartOf="@+id/dialpad_6"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/dialpad_4"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_6"
        style="@style/DialpadNumberStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginRight="@dimen/activity_margin"
        android:text="6"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_9"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/dialpad_5"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_6_letters"
        style="@style/DialpadLetterStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginRight="@dimen/activity_margin"
        android:text="MNO"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_9"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/dialpad_5"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_7"
        style="@style/DialpadNumberStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/activity_margin"
        android:text="7"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_asterisk"
        app:layout_constraintEnd_toStartOf="@+id/dialpad_8"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_7_letters"
        style="@style/DialpadLetterStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/activity_margin"
        android:text="PQRS"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_asterisk"
        app:layout_constraintEnd_toStartOf="@+id/dialpad_8"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_8"
        style="@style/DialpadNumberStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="8"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_0_holder"
        app:layout_constraintEnd_toStartOf="@+id/dialpad_9"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/dialpad_7"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_8_letters"
        style="@style/DialpadLetterStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="TUV"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_0_holder"
        app:layout_constraintEnd_toStartOf="@+id/dialpad_9"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/dialpad_7"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_9"
        style="@style/DialpadNumberStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="@dimen/activity_margin"
        android:text="9"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_hashtag"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/dialpad_8"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_9_letters"
        style="@style/DialpadLetterStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="@dimen/activity_margin"
        android:text="WXYZ"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_hashtag"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/dialpad_8"/>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_asterisk"
        style="@style/DialpadNumberStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/activity_margin"
        android:text="*"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_call_button"
        app:layout_constraintEnd_toStartOf="@+id/dialpad_0_holder"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"/>

    <RelativeLayout
        android:id="@+id/dialpad_0_holder"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:background="?attr/selectableItemBackgroundBorderless"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_call_button"
        app:layout_constraintEnd_toStartOf="@+id/dialpad_hashtag"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/dialpad_asterisk">

        <com.simplemobiletools.commons.views.MyTextView
            android:id="@+id/dialpad_0"
            style="@style/DialpadNumberStyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:text="0"/>

        <com.simplemobiletools.commons.views.MyTextView
            android:id="@+id/dialpad_plus"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignTop="@+id/dialpad_0"
            android:layout_alignBottom="@+id/dialpad_0"
            android:layout_centerHorizontal="true"
            android:layout_toEndOf="@+id/dialpad_0"
            android:gravity="center"
            android:paddingStart="@dimen/small_margin"
            android:paddingTop="@dimen/small_margin"
            android:text="+"
            android:textSize="@dimen/actionbar_text_size"/>

    </RelativeLayout>

    <com.simplemobiletools.commons.views.MyTextView
        android:id="@+id/dialpad_hashtag"
        style="@style/DialpadNumberStyle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="@dimen/activity_margin"
        android:text="#"
        app:layout_constraintBottom_toTopOf="@+id/dialpad_call_button"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/dialpad_0_holder"/>

    <ImageView
        android:id="@+id/dialpad_call_button"
        android:layout_width="@dimen/dialpad_button_size"
        android:layout_height="@dimen/dialpad_button_size"
        android:layout_marginBottom="@dimen/activity_margin"
        android:background="@drawable/circle_background"
        android:elevation="@dimen/medium_margin"
        android:padding="@dimen/normal_margin"
        android:src="@drawable/ic_phone_vector"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"/>

</androidx.constraintlayout.widget.ConstraintLayout>