如何与Sailfish Silica/QML中Slider的值交互

How to interact with the value of a Slider in Sailfish Silica / QML?

本文关键字：Slider 交互 QML Sailfish Silica      更新时间：2023-10-16

我似乎完全迷失在QML中的表单声明中。我有一个具有正确设置的Q_PROPERTies的C++对象，我可以访问QML中该类的对象，并且我想在QML中使用滑块。如何使Slider的值准确地更新对象中特性的信息，反之亦然？

如果它类似于常规QML，那么以下方法将起作用。

Context属性

使用显式绑定或使用Slider的值Changed信号：

#include <QGuiApplication>
#include <QtQml>
class Object : public QObject
{
    Q_OBJECT
    Q_PROPERTY(qreal value READ value WRITE setValue NOTIFY valueChanged)
public:
    explicit Object(QObject *parent = 0) :
        QObject(parent),
        mValue(0)
    {
    }
    qreal value() const {
        return mValue;
    }
    void setValue(qreal value) {
        if (value != mValue) {
            mValue = value;
            emit valueChanged();
        }
    }
signals:
    qreal valueChanged();
private:
    qreal mValue;
};
int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);
    Object object;
    QQmlApplicationEngine engine;
    engine.rootContext()->setContextProperty("object", &object);
    engine.load(QUrl(QStringLiteral("qrc:///main.qml")));
    return app.exec();
}
#include "main.moc"

main.qml:

import QtQuick 2.3
import QtQuick.Controls 1.2
ApplicationWindow {
    width: 400
    height: 400
    visible: true
    Binding {
        target: object
        property: "value"
        value: slider.value
    }
    Slider {
        id: slider
        // You can also react to the valueChanged signal of Slider:
        //onValueChanged: object.value = value
    }
}

注册QML类型

使用简单的绑定：

#include <QGuiApplication>
#include <QtQml>
class Object : public QObject
{
    Q_OBJECT
    Q_PROPERTY(qreal value READ value WRITE setValue NOTIFY valueChanged)
public:
    explicit Object(QObject *parent = 0) :
        QObject(parent),
        mValue(0)
    {
    }
    qreal value() const {
        return mValue;
    }
    void setValue(qreal value) {
        if (value != mValue) {
            mValue = value;
            emit valueChanged();
        }
    }
signals:
    qreal valueChanged();
private:
    qreal mValue;
};
int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);
    qmlRegisterType<Object>("Test", 1, 0, "Object");
    QQmlApplicationEngine engine;
    engine.load(QUrl(QStringLiteral("qrc:///main.qml")));
    return app.exec();
}
#include "main.moc"

main.qml:

import QtQuick 2.3
import QtQuick.Controls 1.2
import Test 1.0
ApplicationWindow {
    width: 400
    height: 400
    visible: true
    Object {
        id: object
        value: slider.value
        onValueChanged: print(value)
    }
    Slider {
        id: slider
    }
}
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