connections 使用

import QtQuick 2.9import QtQuick.Window 2.2Window {    visible: true    width: 640    height: 480    title: qsTr("Hello World")    Rectangle{        visible: true        id: rect        width: 100        height: 100        color: "#000000"        MouseArea{            id:mousea            anchors.fill: parent        }        Connections{            target: mousea            onClicked:rect.color = Qt.rgba(Math.random(),Math.random(),Math.random(),1)        }    }}