C++和 QML 集成,似乎无法访问属性

发布于 2024-12-07 00:56:06 字数 1060 浏览 1 评论 0原文

好的。所以我以为我已经完全理解了这一点,但显然我做错了一些事情,而且我一生都无法理解什么。我已严格按照教程进行操作(我检查过),但无法使其正常工作,所以在这里,让我问一个简单的问题。

我创建了一个基于 QObject 的类,它有一个简单的 QString 变量,用于存储类的名称(这仅用于测试),它看起来像这样:

#include <QObject>

class CategoryPane : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString catName READ getCategoryName WRITE setCategoryName);

public:
    explicit CategoryPane(QObject *parent = 0);

    QString getCategoryName();
    void setCategoryName(QString);

signals:
    void nameChange();

private:
    QString categoryName;
};

这是使用以下函数注册的: qmlRegisterType("ITI_UI", 1, 0, "类别窗格");

我试图在 QML 文件中打印出我的 CategoryPane 类的名称变量,如下所示:

import QtQuick 1.0
import ITI_UI 1.0

Rectangle {
    width: 300
    height: 300

    CategoryPane {
        id: whatever
        catName: "ey"
        Text {
            text: whatever.catName
        }
    }
}

但出现以下错误: qrc:/main.qml:11:3: Cannot allocate to non-existent default属性

注意:如果删除 Text {} 字段,我不会收到错误消息,但我又无法打印出我的姓名字符串,这就是重点...

提前感谢您的时间和耐心!

Ok. So I thought i had understood this completely, but obiously I have done something wrong and I can't for the life of me understand what. I've followed the tutorials to the letter (i checked) but can't get it to work, so here, let me ask a simple question.

I've created a QObject based class which has a simple QString variable that stores the name of the class (this is just for testing), it looks like this:

#include <QObject>

class CategoryPane : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString catName READ getCategoryName WRITE setCategoryName);

public:
    explicit CategoryPane(QObject *parent = 0);

    QString getCategoryName();
    void setCategoryName(QString);

signals:
    void nameChange();

private:
    QString categoryName;
};

This is registered with the following function: qmlRegisterType("ITI_UI", 1, 0, "CategoryPane");

And I'm trying to print out the name variable of my CategoryPane class in a QML-file that looks like this:

import QtQuick 1.0
import ITI_UI 1.0

Rectangle {
    width: 300
    height: 300

    CategoryPane {
        id: whatever
        catName: "ey"
        Text {
            text: whatever.catName
        }
    }
}

But I get the following error: qrc:/main.qml:11:3: Cannot assign to non-existent default property

Note: I get no error msg if I remove the Text {} field, but then again I can't print out my name string which is the whole point...

Thanks in advance for your time and patience!

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樱&纷飞 2024-12-14 00:56:06

CategoryPane 像可视项一样使用,但它派生自 QObject。您是否尝试过从 QDeclarativeItem 继承?

如果您只想访问该属性而不是将其用作可视项,则应该能够执行以下操作:

C++:

QDeclarativeView view;
CategoryPane pane;
view.rootContext()->setContextProperty("categoryPane", &pane);

QML:

import QtQuick 1.0

Rectangle {
    width: 300
    height: 300

    Text {
        text: categoryPane.catName
    }
}

CategoryPane is being used like a visual item, but it derives from QObject. Have you tried inheriting from QDeclarativeItem instead?

If you just want to access the property and not use it as a visual item, you should be able to do like:

C++:

QDeclarativeView view;
CategoryPane pane;
view.rootContext()->setContextProperty("categoryPane", &pane);

QML:

import QtQuick 1.0

Rectangle {
    width: 300
    height: 300

    Text {
        text: categoryPane.catName
    }
}
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