Add a Chronometer Widget

<Chronometer

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:id="@+id/chronometer2"

    android:format="H:MM:SS"

    android:text="Chronometer"

    android:layout_marginStart="16dp"

    app:layout_constraintLeft_toLeftOf="parent"

    android:layout_marginEnd="16dp"

    app:layout_constraintRight_toRightOf="parent"

    android:layout_marginTop="16dp"

    app:layout_constraintTop_toBottomOf="@+id/textClock2"

    android:visibility="visible"

    android:textAppearance="@style/TextAppearance.AppCompat.Display2" />