Why does this custom view switch keyboards and loose focus

In my custom view when I click on the edittext at first the correct keyboard is displayed (with only numbers) but after a few seconds the the keyboard is switched to standard keyboard and edittext looses focus.

Why is this happening.

Here is the code of the my custo view:

public class SetValueView extends RelativeLayout
{
    private ImageView minusButton;
    private ImageView plusButton;
    private EditText valueField;

    public SetValueView(Context context)
    {
        super(context);
        init(context);
    }

    public SetValueView(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        init(context);
    }

    public SetValueView(Context context, AttributeSet attrs, int defStyle)
    {
        super(context, attrs, defStyle);
        init(context);
    }

    private void init(Context context)
    {
        LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View rootView = layoutInflater.inflate(R.layout.vg_set_value, this);

        this.minusButton = (ImageView) rootView.findViewById(R.id.icon_minus);
        this.plusButton = (ImageView) rootView.findViewById(R.id.icon_plus);
        this.valueField = (EditText) rootView.findViewById(R.id.field_value);
    }

}

And here is the vg_set_layout.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://ift.tt/nIICcg"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/view_set_value_background" >

    <ImageView
        android:id="@+id/icon_minus"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/field_value"
        android:layout_alignTop="@+id/field_value"
        android:background="@drawable/button_background"
        android:clickable="true"
        android:src="@drawable/ic_minus" />

    <EditText
        android:id="@+id/field_value"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@id/icon_minus"
        android:background="@drawable/view_set_value_value_background"
        android:gravity="right"
        android:inputType="numberDecimal"
        android:minWidth="50dp"
        android:padding="2dp"
        android:textSize="15sp" />

    <ImageView
        android:id="@+id/icon_plus"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@id/field_value"
        android:layout_alignTop="@id/field_value"
        android:layout_toRightOf="@id/field_value"
        android:background="@drawable/button_background"
        android:clickable="true"
        android:scaleType="centerInside"
        android:src="@drawable/ic_plus" />

</RelativeLayout>