How to read xml's KeyBoard component in android

I am reading an android application where they use Keyboard Component in XML.This is as follow:

<Keyboard xmlns:android="http://ift.tt/nIICcg"
xmlns:ask="http://ift.tt/1kH5uHG"
android:keyWidth="10%p"
android:keyHeight="@integer/key_normal_height">

 <Row>
    <Key android:codes="\uE32A" android:keyEdgeFlags="left"/>
    <Key android:codes="\uE32B"/>
    <Key android:codes="\uE32C"/>
    <Key android:codes="\uE32D" />
    <Key android:codes="\uE023"/>
    <Key android:codes="\uE022" />
    <Key android:codes="\uE327"/>
    <Key android:codes="\uE328" />
    <Key android:codes="\uE329" />
    <Key android:codes="\uE437" android:keyEdgeFlags="right"/>
</Row>


<Row  android:rowEdgeFlags="bottom" >
  <Key android:codes="@integer/key_code_mode_alphabet" ask:longPressCode="@integer/key_code_mode_alphabet_popup" android:drawable="@drawable/sym_keyboard_globe" android:keyEdgeFlags="left"/>  

    <Key ask:isFunctional="true" android:codes="-93" android:keyLabel="1"/>
    <Key android:background="@drawable/btn_keyboard_key_action_pressed" android:codes="-92" android:keyLabel="2"/>
    <Key ask:isFunctional="true" android:codes="-91" android:keyLabel="3"/>
    <Key ask:isFunctional="true" android:codes="-90" android:keyLabel="4"/>
    <Key ask:isFunctional="true" android:codes="-89" android:keyLabel="5"/>
    <Key ask:isFunctional="true" android:codes="-88" android:keyLabel="6"/>
    <Key ask:isFunctional="true" android:codes="-87" android:keyLabel="7"/>
    <Key ask:isFunctional="true" android:codes="-86" android:keyLabel="8"/>

    <Key android:codes="-5" android:keyEdgeFlags="right" android:isRepeatable="true"/>
</Row> 
</Keyboard>

I want to know how this Keyboard works (for example when i press the key)?