发帖 回复
返回列表
  • 5905阅读
  • 2回复

[提问]QML中调用C++方法出现问题，求救 [复制链接]

 上一主题 下一主题
离线cycloneii
侠客
 
只看楼主 倒序阅读 楼主  发表于: 2013-05-14
我从QObject派生了一个类InvokableObject， 内容如下
InvokableObject.h
复制代码
  1. #ifndef INVOKEABLEOBJ_H
  2. #define INVOKEABLEOBJ_H
  4. #include <QObject>
  5. #include <QVariant>
  7. class InvokeableObj : public QObject
  8. {
  9.     Q_OBJECT
  10. public:
  11.     explicit InvokeableObj(QObject *parent = 0);
  12.     Q_INVOKABLE QVariant getOptionValue(QString key) const { return key;}
  14. signals:
  15.     
  16. public slots:
  17.     
  18. };
  20. #endif // INVOKEABLEOBJ_H
InvokableObject.cpp
复制代码
  1. #include "invokeableobj.h"
  2. #include <QtDeclarative>
  4. InvokeableObj::InvokeableObj(QObject *parent) :
  5.     QObject(parent)
  6. {
  7. }
main.cpp
复制代码
  1. #include <QApplication>
  2. #include <QtDeclarative>
  3. #include "invokeableobj.h"
  4. #include "qmlapplicationviewer.h"
  6. Q_DECL_EXPORT int main(int argc, char *argv[])
  7. {
  8.     QScopedPointer<QApplication> app(createApplication(argc, argv));
  10.     QmlApplicationViewer viewer;
  11.     viewer.setOrientation(QmlApplicationViewer::ScreenOrientationAuto);
  12.     viewer.setMainQmlFile(QLatin1String("qml/testinvokable/main.qml"));
  13.     viewer.showExpanded();
  15.     viewer.rootContext()->setContextProperty("testobject", new InvokeableObj(&viewer));
  17.     return app->exec();
  18. }
main.qml
复制代码
  1. // import QtQuick 1.0 // to target S60 5th Edition or Maemo 5
  2. import QtQuick 1.1
  4. Rectangle {
  5.     width: 360
  6.     height: 360
  7.     Text {
  8.         id: text1
  9.         text: testobject.getOptionValue("ipaddress")
  10.         anchors.centerIn: parent
  11.     }
  13.     MouseArea {
  14.         anchors.fill: parent
  15.         onClicked: {
  16.             Qt.quit();
  17.         }
  18.     }
  19. }
可以在qml中调用InvokableObject的getOptionValue方法
但是如果将InvokableObject的基类改成QDeclarativePropertyMap，那么就会报错，TypeError: Result of expression 'testobject.getOptionValue' [undefined] is not a function.

为什么QObject做基类，工作正常，从QDeclarativePropertyMap派生就不能调用了getOptionValue方法了呢？
回复
举报
分享到 淘江湖 新浪 QQ微博 QQ空间 开心 人人 豆瓣 网易微博 百度 鲜果 白社会 飞信
离线cavendish
骑士
只看该作者 1楼 发表于: 2013-05-14
http://doc-snapshot.qt-project.org/4.8/qml-extending.html

QML relies heavily on Qt's meta object system and can only instantiate classes that derive from QObject. For visual element types, this will usually mean a subclass of QDeclarativeItem; for models used with the view elements, a subclass of QAbstractItemModel; and for arbitrary objects with properties, a direct subclass of QObject.
My Blog: http://www.qiliang.net/blog/
My Homepage: http://www.qiliang.net
回复
举报
离线cycloneii
侠客
只看该作者 2楼 发表于: 2013-05-15
引用第1楼cavendish于2013-05-14 23:56发表的  :
http://doc-snapshot.qt-project.org/4.8/qml-extending.html
QML relies heavily on Qt's meta object system and can only instantiate classes that derive from QObject. For visual element types, this will usually mean a subclass of QDeclarativeItem; for models used with the view elements, a subclass of QAbstractItemModel; and for arbitrary objects with properties, a direct subclass of QObject.

并不一定要是QObject的直接子类，比如如果InvokableObject从QSettings派生，那么qml依然可以调用getOptionValue方法，但是换成QDeclarativePropertyMap就不行。其中应该还有其他的原因吧
回复
举报
发帖 回复
返回列表
快速回复
限100 字节
 
上一个 下一个