MouseArea{
            anchors.fill: parent
            onClicked:
               // rect.y=150
                PropertyAnimation{
                    target:rect
                    properties:"y"
                     to:150
                     duration:1000
                     onStarted: {
                         console.log("start")
                     }
                     onStopped: {
                         console.log("stoped")
                     }
                }
        }
这一段代码就可以
下面这个为啥就不行啊
 Behavior on y {
            PropertyAnimation{
             //   target: rect
                id:aa
                duration:1000
                onStarted: {
                    console.log("start")
                }
                onStopped: {
                    console.log("stoped")
                }
            }
        
        }