小编Mic*_*jan的帖子

我有一个固定大小的矩形，它应该始终附着在窗口垂直中心的底部。如果窗口高度足够小，使得矩形能够接触边框，我想更改矩形的锚点，使其粘在窗口的底部。

我使用状态实现了这一点：

import QtQuick 2.15
import QtQuick.Window 2.15

Window {
    id: window
    width: 200
    height: 480
    minimumHeight: maxSize
    visible: true

    property int maxSize: 150
    property bool centerTop: maxSize < (height / 2)

    Rectangle {
        id: rect

        states: [
            State {
                name: "Centered"
                when: centerTop
                PropertyChanges {
                    target: rect
                    anchors.top: parent.verticalCenter
                    anchors.bottom: undefined
                }
            },
            State {
                name: "Bottom"
                when: !centerTop
                PropertyChanges {
                    target: rect
                    anchors.top: undefined
                    anchors.bottom: parent.bottom
                }
            }
        ]
        anchors.left: parent.left
        anchors.right: parent.right
        anchors.leftMargin: 10
        anchors.rightMargin: 10
        height: …