qml几种加载方式的区别

前言

1、QQmlApplicationEngine+window

此方式加载QML ：QML 拥有窗口的完整控制权，可以直接设置标题、窗口尺寸等属性

#include <QGuiApplication>
#include <QQmlApplicationEngine>

int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);

    QQmlApplicationEngine engine;
    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
    if (engine.rootObjects().isEmpty())
        return -1;

    return app.exec();
}

2、QQuickView+Item

此方式加载QML ：对窗口的控制权（标题、窗口尺寸）是在 C++代码中，QML 文件是以 Item （及 以Item为根的组件）作为根对象

#include <QGuiApplication>
#include <QQuickView>
int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);

    QQuickView *view = new QQuickView;
    view->setResizeMode(QQuickView::SizeRootObjectToView);
    view->setSource(QUrl(QStringLiteral("qrc:/main.qml")));
    view->show();

    return app.exec();
}

3、QQuickWidget

此方式加载QML ：QQuickWidget是继承于 QWidget 控件，这种方式主要是用于在 QWidget 界面上加载 QML 界面

QQuickWidget *view = new QQuickWidget;
view->setSource(QUrl::fromLocalFile("myqmlfile.qml"));
view->show();

QWidget中加载QML页面并设置透明背景

    m_pQuickWidget = new QQuickWidget(this);
    m_pQuickWidget->setFixedSize(1131,586);
    m_pQuickWidget->setAttribute(Qt::WA_AlwaysStackOnTop);
    m_pQuickWidget->setClearColor(QColor(Qt::transparent)); // 重要
    m_pQuickWidget->setSource(QUrl(QStringLiteral("qrc:/UI/Viewer.qml")));
    m_pQuickWidget->rootObject()->setWidth(1131);
    m_pQuickWidget->rootObject()->setHeight(586);
    m_pQuickWidget->move(this->width()/2.0 - m_pQuickWidget->width()/2.0,342);
    m_pQuickWidget->show();

参考

https://blog.csdn.net/luoyayun361/article/details/77113516/

https://blog.csdn.net/qq_37996632/article/details/113284468

https://blog.csdn.net/qq_34139994/article/details/105195447