Stopping and Restarting while in the background. (Save my Batt.)

[NKinney.Econolite]

Qt 5.1.1 and QtQuick 2.0 on Android. I have a program that shuffles over a list of colors. While running on the device if I put the application into the background by hitting home. The Application keeps running while in the background. I would like to stop this then restart it when the application is no longer in the background. How is this accomplished in Qt?

@import QtQuick 2.0

Rectangle {
width: 1280
height: 800
color: colorList[colorNdx]
property variant colorList: ["red", "orange", "yellow", "green", "blue", "indigo", "violet", "white", "black"]
property int colorNdx: 0
property int colorCount: colorList.length

Rectangle {
    anchors.centerIn: parent
    width: 100
    height: 100
    color: "khaki"
    border.color: "black"
    border.width: 3
    radius: 50

    Text {
        anchors.centerIn: parent
        text: qsTr("Quit")
    }

    MouseArea {
        anchors.fill: parent
        onPressed: parent.color = "pink"
        onReleased: Qt.quit()
    }
}

Timer {
     interval: 2000
     running: true
     repeat: true
     onTriggered:{
         colorNdx = colorNdx === (colorCount - 1) ? 0 : (colorNdx + 1)
         console.log("color =>", colorList[colorNdx])
     }
}

}
@