awtk/design/default/ui/soft_keyboard.xml

<window text="Custom Soft Keyboard" anim_hint="htranslate" 
  move_focus_up_key="up" move_focus_down_key="down" move_focus_left_key="left" move_focus_right_key="right">
  <edit x="c" y="10" w="90%" h="30" focused="true" input_type="custom" text="" tips="custom"/>

  <view y="60" x="c" w="90%" h="-60" is_keyboard="true" grab_keys="true" 
    children_layout="default(r=4,c=4,m=5,s=5)" >
    <button focusable="true"  name="key" text="0" />
    <button focusable="true"  name="key" text="1" />
    <button focusable="true"  name="key" text="2" />
    <button focusable="true"  name="key" text="3" />
    <button focusable="true"  name="key" text="4" />
    <button focusable="true"  name="key" text="5" />
    <button focusable="true"  name="key" text="6" />
    <button focusable="true"  name="key" text="7" />
    <button focusable="true"  name="key" text="8" />
    <button focusable="true"  name="key" text="9" />
    <button focusable="true"  name="key" text="#" />
    <button focusable="true"  name="backspace" text="<=" />
  </view>
  <button name="close" self_layout="default(x=center,y=bottom:50,w=50%,h=30)" 
    floating="true" text="Close"/>
</window>