qml學習中遇到的一些問題

import QtQuick 2.12
import QtQuick.Window 2.12

Window {
    visible: true
    width: 640
    height: 480
    color: "black"
    title: qsTr("Hello World")

    Grid {
        x:100;y:100
        spacing: 10
        columns: 2
        Rectangle{
            id:rect1
            width:100;height: 100
            color: focus?"#2FA7C2":"lightblue"
            focus: true

            
            KeyNavigation.right: rect2
            KeyNavigation.down: rect3


            //設置鼠標區域
            MouseArea{
                id:mouse_area1
                anchors.fill: parent
                onClicked: {
                        focus = true;
                        parent.color = "#2FA7C2"
                }
            }
        }
        Rectangle{
            id:rect2
            width:100;height: 100
            color:focus?"green" :"lightgreen"
            KeyNavigation.left:  rect1
            KeyNavigation.down: rect4
        }
        Rectangle{
            id:rect3
            width:100;height: 100
            color: focus?"gray":"lightgray"
            KeyNavigation.right: rect4
            KeyNavigation.up: rect1
        }
        Rectangle{
            id:rect4
            width:100;height: 100
            color: focus?"#570A78":"#9A5FA7"
            KeyNavigation.left: rect3
            KeyNavigation.up: rect2
        }


        //添加鼠交互 如何實現呢？？？

    }

}