fix: DPlatformTheme::property not work

[kegechen]

buildNativeSettings 之后 metaobject 被替换了
不会走原来的 read 方法了。
这里如果读取时 xsettings 中如果没有 fallback 到
base 对象的 read 方法

Issue: linuxdeepin/dtk#101

[zccrs]

应该不会有这种低级错误才对，确定这里应该加上 m_propertyCount ？会不会导致原本应该从 m_settings 里读取的属性读不到了？

[kegechen]

问题说的就是调用属性的 read 方法 themeName 可以, 无法通过 property("themeName") 读取到正确的值。

QByteArray DPlatformTheme::themeName() const
{
//    FETCH_PROPERTY("Net/ThemeName", themeName)
    D_DC(DPlatformTheme);
    QVariant value = d->theme->getSetting(QByteArrayLiteral("Net/ThemeName"));
    if (d->fallbackProperty && !value.isValid() && d->parent)
        return d->parent->themeName();

    return value.toByteArray();
}

themeName() 会通过私有成员 d->theme ->getSetting 获取 xsettings 中的 Net/ThemeName，如果直接 property("themeName") 会到 xsettings 中去读 themeName 自然是读不到的无效值。

修改方案就是 如果是原来的属性就 fallback 到源对象的 read 方法，即 m_base->qt_metacall(_c, _id, _a);

[kegechen]

class Q_GUI_EXPORT QGuiApplication : public QCoreApplication
{
    Q_OBJECT
    Q_PROPERTY(QIcon windowIcon READ windowIcon WRITE setWindowIcon)
    Q_PROPERTY(QString applicationDisplayName READ applicationDisplayName WRITE setApplicationDisplayName NOTIFY applicationDisplayNameChanged)
    Q_PROPERTY(QString desktopFileName READ desktopFileName WRITE setDesktopFileName)
    Q_PROPERTY(Qt::LayoutDirection layoutDirection READ layoutDirection WRITE setLayoutDirection NOTIFY layoutDirectionChanged)
    Q_PROPERTY(QString platformName READ platformName STORED false)
    Q_PROPERTY(bool quitOnLastWindowClosed  READ quitOnLastWindowClosed WRITE setQuitOnLastWindowClosed)
    Q_PROPERTY(QScreen *primaryScreen READ primaryScreen NOTIFY primaryScreenChanged STORED false)
}

    const QMetaObject *metaObj = qGuiApp->metaObject();
    QMetaObjectBuilder ob;
    ob.addMetaObject(metaObj);
    int offset = metaObj->propertyOffset();
    int count = ob.propertyCount(); // metaObj->propertyCount();包含了 parent 的 property
    for (int i = offset; i < count + offset; ++i) {
        qInfo() << "[" << i << "]" << metaObj->property(i).name();
    }

[ 6 ] windowIcon
[ 7 ] applicationDisplayName
[ 8 ] desktopFileName
[ 9 ] layoutDirection
[ 10 ] platformName
[ 11 ] quitOnLastWindowClosed
[ 12 ] primaryScreen

[deepin-ci-robot]

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This pull-request has been approved by: 18202781743, kegechen

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