activity main

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:orientation="vertical"
    tools:context="com.robillo.customviewstutorial.MainActivity">

    <com.robillo.customviewstutorial.MyCustomView
        android:layout_width="300sp"
        android:layout_height="0sp"
        app:square_color="@color/colorPrimary"
        android:layout_weight="1"
        android:layout_margin="5sp"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:layout_width="0sp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:id="@+id/one"
            android:onClick="onClick"
            style="?android:attr/buttonBarStyle"
            android:background="?attr/selectableItemBackground"
            android:text="CUSTOM PADDING +"/>

        <Button
            android:layout_width="0sp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:id="@+id/two"
            android:onClick="onClick"
            style="?android:attr/buttonBarStyle"
            android:background="?attr/selectableItemBackground"
            android:text="SWAP COLOR"/>

        <Button
            android:layout_width="0sp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:id="@+id/three"
            android:onClick="onClick"
            style="?android:attr/buttonBarStyle"
            android:background="?attr/selectableItemBackground"
            android:text="CUSTOM PADDING -"/>

    </LinearLayout>

</LinearLayout>