轮播图是一个常见的功能,在QML中,可以使用PathView来实现一个循环播放的轮播图组件。
默认情况,如果限制了加载个数,切换时第一帧会马上消失,第二帧才进入,这样会有断档的感觉。通过设置PathView中preferredHighlightBegin/End为0.5,这样当前选定的项位于路径的中间,就没有断档的感觉了。效果如下(为了测试,我没有clip,clip之后只有范围内的才可见):
//CircleView.qml
import QtQuick 2.12 import QtQuick.Controls 2.12 //轮播图 Item { id: control property int indicatorWidth: 12 //定时切换间隔 property alias timerInterval: path_timer.interval //切换动画执行时间 property alias pathDuration: path_view.highlightMoveDuration property alias delegate: path_view.delegate property alias model: path_view.model //页数 property alias count: path_page.count PathView{ id: path_view anchors.fill: parent //此属性保存任何时候在路径上可见的项目数。 //将pathItemCount设置为undefined将显示路径上的所有项目。 //因为path代码的问题,设置为2最合适 pathItemCount: 2 //测试时,把clip去掉就能看到完整的 //clip: true //向前移动,即顺序0 1 2 3 movementDirection: PathView.Positive //切换的时间 highlightMoveDuration: 1000 //视图中突出显示(当前项目)的首选范围,默认值PathView.StrictlyEnforceRange //配合preferredHighlight的范围0.5 0.5,就能显示在正中,切换更自然 //highlightRangeMode: PathView.StrictlyEnforceRange //希望当前选定的项位于路径的中间,则将突出显示范围设置为0.5,0.5 preferredHighlightBegin: 0.5 preferredHighlightEnd: 0.5 path: Path { startX: -path_view.width/2 startY: path_view.height / 2 PathLine { x: path_view.pathItemCount * path_view.width-path_view.width / 2 y: path_view.height / 2 } } onModelChanged: { if(path_timer.running){ path_timer.restart(); } } //测试用 //model: ["red","green","blue"] //delegate: Rectangle{ // width: path_view.width // height: path_view.height // color: modelData //} } //定时切换 Timer{ id: path_timer running: control.visible repeat: true interval: 3000 onTriggered: { //至少两个才切换 if(path_view.count>1) path_view.currentIndex=(path_view.currentIndex+1)%path_view.count } } //右下角小圆圈 PageIndicator { id: path_page anchors{ right: parent.right bottom: parent.bottom margins: 30 } count: path_view.count currentIndex: path_view.currentIndex spacing: control.indicatorWidth delegate: Rectangle{ width: control.indicatorWidth height: width radius: width/2 color: "white" //非当前页就灰色 opacity: index===path_page.currentIndex?1:0.6 Behavior on opacity { OpacityAnimator{ duration: 200 } } //点击跳转到该页 //还有问题,非连续的item,他会快速连续切换到目标index //因为不是直接切换,有闪烁的感觉 MouseArea{ anchors.fill: parent onClicked: { path_view.currentIndex=index; if(path_timer.running){ path_timer.restart(); } } } } } }
//main.qml
测试了不同的Item个数
import QtQuick 2.12 import QtQuick.Window 2.12 import QtQuick.Controls 2.12 Window { visible: true width: 700 height: 500 title: qsTr("龚建波 1992") color: "#021B39" Column{ anchors.centerIn: parent spacing: 10 CircleView{ width: 100 height: 50 model:["red","green","blue","orange"] delegate: Rectangle { width: 100 height: 50 color: modelData //Component.onCompleted: console.log(modelData,"completed") } Rectangle{ anchors.fill: parent color: "transparent" border.color: "white" } } CircleView{ width: 100 height: 50 model:["red","green","blue"] delegate: Rectangle { width: 100 height: 50 color: modelData //Component.onCompleted: console.log(modelData,"completed") } Rectangle{ anchors.fill: parent color: "transparent" border.color: "white" } } CircleView{ width: 100 height: 50 model:["red","green"] delegate: Rectangle { width: 100 height: 50 color: modelData //Component.onCompleted: console.log(modelData,"completed") } Rectangle{ anchors.fill: parent color: "transparent" border.color: "white" } } CircleView{ width: 100 height: 50 model:["red"] delegate: Rectangle { width: 100 height: 50 color: modelData //Component.onCompleted: console.log(modelData,"completed") } Rectangle{ anchors.fill: parent color: "transparent" border.color: "white" } } CircleView{ width: 100 height: 50 delegate: Rectangle { width: 100 height: 50 color: modelData //Component.onCompleted: console.log(modelData,"completed") } Rectangle{ anchors.fill: parent color: "transparent" border.color: "white" } } } }
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