使用 Signals/Slots 控制 Qt QML SwipeView

Question

我是 Qt 的新手，现在正在努力弄清楚如何通过不同的 C++ class 更改 SwipeView 的索引。我想发出某种从 C++ class 发出的信号，说 "Swipe Right" 或类似的东西，并让 SwipeView 响应。我也是信号和槽的新手，所以我可能误解了它们的工作原理。

Answer 1

当你想从 C++ 控制一个 QML 元素时，最好的策略是创建一个 QObject 具有 Q_PROPERTY、插槽和信号并将其导出到 QML到setContextProperty()，直接绑定或者使用Connections连接信号，此时只需要在QML.

发出信号连接即可

在下面的示例中，我展示了如何使用 QPushButton 向右或向左切换：

main.cpp

#include <QApplication>
#include <QPushButton>
#include <QQmlApplicationEngine>
#include <QQmlContext>
#include <QHBoxLayout>

class SwipeManager: public QObject{
    Q_OBJECT
public:
    using QObject::QObject;
public slots:
    void moveToRight(){
        emit toRight();
    }
    void moveToLeft(){
        emit toLeft();
    }
signals:
    void toRight();
    void toLeft();
};

int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

    QApplication app(argc, argv);
    SwipeManager manager;

    QQmlApplicationEngine engine;
    engine.rootContext()->setContextProperty("manager", &manager);
    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
    if (engine.rootObjects().isEmpty())
        return -1;

    QWidget w;
    QPushButton left("to left");
    QPushButton right("to right");
    QHBoxLayout *lay = new QHBoxLayout(&w);
    lay->addWidget(&left);
    lay->addWidget(&right);
    QObject::connect(&left, &QPushButton::clicked, &manager, &SwipeManager::moveToLeft);
    QObject::connect(&right, &QPushButton::clicked, &manager, &SwipeManager::moveToRight);
    w.show();

    return app.exec();
}

#include "main.moc"

main.qml

import QtQuick 2.9
import QtQuick.Window 2.2
import QtQuick.Controls 2.4

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("SwipeView Test")

    SwipeView {
        id: view
        anchors.fill: parent
        currentIndex: 4
        Repeater {
            model: 10
            Loader {
                active: SwipeView.isCurrentItem || SwipeView.isNextItem || SwipeView.isPreviousItem
                sourceComponent: Item{
                    Text {
                        text: "Page: "+index
                        anchors.centerIn: parent
                    }
                }
            }
        }
    }
    Connections{
        target: manager
        onToRight: if(view.currentIndex + 1 != view.count) view.currentIndex += 1
        onToLeft: if(view.currentIndex != 0) view.currentIndex -= 1
    }

    PageIndicator {
        id: indicator

        count: view.count
        currentIndex: view.currentIndex

        anchors.bottom: view.bottom
        anchors.horizontalCenter: parent.horizontalCenter
    }
}

完整的例子可以在下面link.

中找到

使用 Signals/Slots 控制 Qt QML SwipeView

Control Qt QML SwipeView with Signals/Slots

c++

qt

qml

qt5

swipeview