android:layout="@layout/currencycodes"

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:key="application_preferences">
    <PreferenceCategory>
        <PreferenceScreen
                android:key="url_settings"
                android:title="@string/url_settings"
                android:summary="@string/summary_url_settings">
        </PreferenceScreen>

        <PreferenceScreen
                android:key="currency_codes"
                android:title="@string/left_handed"
                android:summary="@string/summary_left_handed">
            <Preference
                    android:key="currency_exchanges"
                    android:layout="@layout/currencycodes"/>
        </PreferenceScreen>
        <EditTextPreference
                android:key="url_exchange_rate"
                android:title="@string/url_exchange_rate_settings"
                android:summary="@string/summary_url_exchange_rate"
                android:enabled = "false"/>
    </PreferenceCategory>
</PreferenceScreen>

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
        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:id="@+id/activity_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:focusable="true"
        android:focusableInTouchMode="true"
        tools:context=".MainActivity">

    <GridView
            android:layout_width="328dp"
            android:layout_height="479dp"
            android:layout_marginTop="16dp"
            app:layout_constraintTop_toTopOf="parent" android:layout_marginStart="16dp"
            app:layout_constraintLeft_toLeftOf="parent" android:layout_marginEnd="16dp"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintBottom_toBottomOf="parent" android:layout_marginBottom="16dp"
            android:id="@+id/grdExchanges" android:scrollbars="horizontal|vertical"
            android:smoothScrollbar="true" tools:textAlignment="center"
            android:verticalScrollbarPosition="defaultPosition"/>
</android.support.constraint.ConstraintLayout>