Unit Conversion App

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp">

    <RadioGroup
        android:id="@+id/unitTypeGroup"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <RadioButton
            android:id="@+id/lengthRadioButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Length" />

        <RadioButton
            android:id="@+id/temperatureRadioButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Temperature" />
    </RadioGroup>

    <EditText
        android:id="@+id/inputBox"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/unitTypeGroup"
        android:layout_marginTop="16dp"
        android:hint="Enter value"
        android:inputType="numberDecimal"
        android:minHeight="48dp" />

    <Spinner
        android:id="@+id/lengthUnitSpinner1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/inputBox"
        android:layout_marginTop="16dp"
        android:entries="@array/length_units"
        android:minHeight="48dp" />

    <Spinner
        android:id="@+id/lengthUnitSpinner2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignTop="@id/lengthUnitSpinner1"
        android:layout_toRightOf="@id/lengthUnitSpinner1"
        android:entries="@array/length_units"
        android:minHeight="48dp" />

    <Spinner
        android:id="@+id/temperatureUnitSpinner1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/inputBox"
        android:layout_marginTop="16dp"
        android:entries="@array/temperature_units"
        android:visibility="gone" />

    <Spinner
        android:id="@+id/temperatureUnitSpinner2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@id/temperatureUnitSpinner1"
        android:layout_alignTop="@id/temperatureUnitSpinner1"
        android:entries="@array/temperature_units"
        android:visibility="gone" />

    <TextView
        android:id="@+id/outputBox"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/lengthUnitSpinner2"
        android:layout_marginTop="16dp"
        android:hint="Converted value"
        android:textSize="18sp" />
</RelativeLayout>