Android custom radio button example

bg_off.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <stroke
        android:width="1dp"
        android:color="@color/black" />
    <corners android:radius="2dp" />

</shape>

bg_on.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <solid android:color="@color/blue" />
    <corners android:radius="2dp" />

</shape>

colors.xml

<resources>
    <color name="white">#FFFFFF</color>
    <color name="black">#000000</color>
    <color name="blue">#35B5E5</color>
</resources>

custom_radio_button_example.xml

<?xml version="1.0" encoding="utf-8"?>
<layout 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">

            <androidx.constraintlayout.widget.ConstraintLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content">
            
                <RadioGroup
                    android:id="@+id/checkRadio"
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:gravity="center"
                    android:orientation="horizontal"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintStart_toStartOf="parent"
                    app:layout_constraintTop_toTopOf="parent">

                    <RadioButton
                        android:id="@+id/check1RB"
                        android:layout_width="100dp"
                        android:layout_height="40dp"
                        android:layout_marginEnd="10dp"
                        android:background="@drawable/radio_button_selector"
                        android:button="@null"
                        android:gravity="center"
                        android:text="CHECK 1"
                        android:textColor="@drawable/radio_button_selector" />

                    <RadioButton
                        android:id="@+id/check2RB"
                        android:layout_width="100dp"
                        android:layout_height="40dp"
                        android:layout_marginEnd="10dp"
                        android:background="@drawable/radio_button_selector"
                        android:button="@null"
                        android:gravity="center"
                        android:text="CHECK 2"
                        android:textColor="@drawable/radio_button_selector" />

                    <RadioButton
                        android:id="@+id/check3RB"
                        android:layout_width="100dp"
                        android:layout_height="40dp"
                        android:background="@drawable/radio_button_selector"
                        android:button="@null"
                        android:gravity="center"
                        android:text="CHECK 3"
                        android:textColor="@drawable/radio_button_selector" />
                </RadioGroup>

            </androidx.constraintlayout.widget.ConstraintLayout>
    

</layout>

radio_button_selector.xml

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:color="@color/white" android:drawable="@drawable/bg_on" android:state_checked="true" android:state_window_focused="false" />
    <item android:color="@color/black" android:drawable="@drawable/bg_off" android:state_checked="false" android:state_window_focused="false" />

    <item android:color="@color/white" android:drawable="@drawable/bg_on" android:state_checked="true" android:state_pressed="true" />
    <item android:color="@color/black" android:drawable="@drawable/bg_off" android:state_checked="false" android:state_pressed="true" />

    <item android:color="@color/white" android:drawable="@drawable/bg_on" android:state_checked="true" android:state_focused="true" />
    <item android:color="@color/black" android:drawable="@drawable/bg_off" android:state_checked="false" android:state_focused="true" />

    <item android:color="@color/black" android:drawable="@drawable/bg_on" android:state_checked="false" />
    <item android:color="@color/white" android:drawable="@drawable/bg_off" android:state_checked="true" />
</selector>