shift-shell/look-and-feel/contents/components/DialerIconButton.qml

import QtQuick 2.0
import org.kde.plasma.core 2.0 as PlasmaCore

Item {
    width: PlasmaCore.Units.iconSizes.smallMedium
    height: width
    property var callback
    property string text
    property string sub
    property alias source: icon.source

    PlasmaCore.IconItem {
        id: icon
        width: PlasmaCore.Units.iconSizes.medium
        height: width
        anchors.centerIn: parent
        colorGroup: PlasmaCore.ColorScope.colorGroup
    }

    MouseArea {
        anchors.fill: parent
        onClicked: {
            if (callback) {
                callback();
            } else {
                addNumber(parent.text);
            }
        }

        onPressAndHold: {
            if (parent.sub.length > 0) {
                addNumber(parent.sub);
            } else {
                addNumber(parent.text);
            }
        }
    }
}