Qt5中QML自定义环形菜单/环形选择框的实现
时间：2022-12-09 09:56:29 | 栏目：C代码 | 点击：次
Qt5 中本身提供了扇形菜单 PieMenu，属于 QtQuick.Extras 模块，这个模块是拓展自 QtQuick.Control1 的，QtQuick.Control1 在 Qt5 高版本被废弃，并在 Qt6 移除。
不过我们也可以用 QtQuick.Control2 的组件自定义样式来实现环形或扇形的菜单和选择框。主要思路就是使用 PathView 来替换默认的 ListView，再改下弹框的背景样式。
ItemDelegate 需要设置给 ComboBox 或者 Menu，而不是 View。最好用 Button 的相关类型（默认是 ItemDelegate 类型），因为组件默认这些小部件是 Button 类型，内部 cast 成按钮来处理的。而且用按钮就不用自己处理下拉框 currentIndex，内部会自己处理，这也避免了我们在这个 delegate 对 currentIndex 赋值后导致其属性绑定失效的问题。
QQuickAction *QQuickMenu::actionAt(int index) const
{
Q_D(const QQuickMenu);
QQuickAbstractButton *item = qobject_cast<QQuickAbstractButton *>(d->itemAt(index));
if (!item)
return nullptr;
return item->action();
}
自定义的时候遇到一点状况，就是 PathView 替代 ListView 作为 Menu 的 contentItem 后，Menu 的 contentData 和 contentModel 始终会多一个表示高亮的 Item，这样环形路径就有个缺口，目前我只能将显示的 Item 个数减去一个来使显示效果正常。
contentItem: PathView {
model: control.contentModel
//把PathView放Menu，会有一个高亮Item被放到contentModel，减去
pathItemCount: control.count > 0 ? control.count - 1 : 0
//... ...
}
Demo 链接：https://github.com/gongjianbo/MyTestCode2021/tree/master/Qml/TestQml_20220313_PathView
主要代码：
import QtQuick 2.12
import QtQuick.Window 2.12
import QtQuick.Controls 2.12
Window {
width: 640
height: 480
visible: true
title: qsTr("PathView")
Row {
anchors.centerIn: parent
spacing: 20
MyComboBox {
model: 10
}
Button {
width: 60
height: 30
text: "menu"
background: Rectangle {
radius: 15
color: "red"
border.color: "black"
}
onClicked: {
menu.popup()
}
MyMenu {
id: menu
anchors.centerIn: parent
Action { text: "1" }
Action { text: "2" }
Action { text: "3" }
Action { text: "4" }
Action { text: "5" }
Action { text: "6" }
Action { text: "7" }
Action { text: "8" }
Action { text: "9" }
Action { text: "10" }
}
}
}
}
import QtQuick 2.12
import QtQuick.Controls 2.12
//环形选择框
//龚建波 2022-03-13
//note：弹框为pop会被限制在window内
ComboBox {
id: control
implicitWidth: 30
implicitHeight: 30
opacity: 0.9999
delegate: ItemDelegate {
width: 30
height: width
padding: 0
background: Rectangle {
radius: width / 2
color: "green"
border.color: "black"
}
contentItem: Text {
text: modelData
padding: 0
verticalAlignment: Text.AlignVCenter
horizontalAlignment: Text.AlignHCenter
}
}
contentItem: Text {
text: control.displayText
padding: 0
verticalAlignment: Text.AlignVCenter
horizontalAlignment: Text.AlignHCenter
}
indicator: null
background: Rectangle {
radius: 15
color: "green"
border.color: "black"
}
popup: Popup {
id: pop
width: 200
height: width
anchors.centerIn: parent
margins: 0
padding: 0
//pathview环形的角度范围和延申半径
property int angle: 1
property int spread: 1
//pop弹出和隐藏时的过渡动画
enter: Transition {
ParallelAnimation {
NumberAnimation { property: "angle"; from: 1; to: 360; duration: 500 }
NumberAnimation { property: "spread"; from: 1; to: 100; duration: 500 }
}
}
exit: Transition {
ParallelAnimation {
NumberAnimation { property: "angle"; from: 360; to: 1; duration: 500 }
NumberAnimation { property: "spread"; from: 100; to: 1; duration: 500 }
}
}
background: Item { }
contentItem: PathView {
model: control.popup.visible ? control.delegateModel : null
//currentIndex: control.highlightedIndex
//highlightRangeMode: PathView.NoHighlightRange
interactive: false
path: Path {
//一个圆环路径
PathAngleArc {
centerX: 100; centerY: 100
radiusX: pop.spread; radiusY: pop.spread
moveToStart: true
startAngle: 0
sweepAngle: pop.angle
}
}
}
}
}
import QtQuick 2.12
import QtQuick.Controls 2.12
//环形菜单
//龚建波 2022-03-13
//note：弹框为pop会被限制在window内
Menu {
id: control
implicitWidth: 250
implicitHeight: 250
margins: 0
padding: 0
//pathview环形的角度范围和延申半径
property int angle: 1
property int spread: 1
//pop弹出和隐藏时的过渡动画
enter: Transition {
ParallelAnimation {
NumberAnimation { property: "angle"; from: 1; to: 360; duration: 500 }
NumberAnimation { property: "spread"; from: 1; to: 100; duration: 500 }
}
}
exit: Transition {
ParallelAnimation {
NumberAnimation { property: "angle"; from: 360; to: 1; duration: 500 }
NumberAnimation { property: "spread"; from: 100; to: 1; duration: 500 }
}
}
delegate: MenuItem {
id: item
width: 30
height: width
padding: 0
spacing: 0
indicator: null
arrow: null
background: Rectangle {
radius: width / 2
color: "red"
border.color: "black"
}
contentItem: Text {
text: item.text
padding: 0
verticalAlignment: Text.AlignVCenter
horizontalAlignment: Text.AlignHCenter
}
}
contentItem: PathView {
implicitWidth: 250
implicitHeight: 250
model: control.contentModel
//把PathView放Menu，会有一个高亮Item被放到contentModel，减去
pathItemCount: control.count > 0 ? control.count - 1 : 0
//currentIndex: control.currentIndex
//highlightRangeMode: PathView.NoHighlightRange
interactive: false
path: Path {
//一个圆环路径
PathAngleArc {
centerX: 125; centerY: 125
radiusX: control.spread; radiusY: control.spread
moveToStart: true
startAngle: 0
sweepAngle: control.angle
}
}
}
background: Item { }
}