High cpu usage in custom QItemDelegate::paint

[rsilva]

I'm using a QItemDelegate to draw controls in a QListView.
But, I've found that makes a high cpu usage 80~100% in my computer.

I think it's happens when I use the buttons, if I have only the progress bar and text there's no high cpu usage.

I'm using the paint to simulate 6 buttons with icons, a progress and one text in each item.

(As my code is a big file I've send it as a attachment.)

Here, my ItemDelegate subclass (only .cpp):
downloaditemdelegate.cpp

for the data for the indexes, I'm using this class:

#ifndef DOWNLOADITEM_H
#define DOWNLOADITEM_H
 
#include <QObject>
#include <QHash>
#include <QVariant>
 
class DownloadItem : public QObject
{
    Q_OBJECT
public:
    explicit DownloadItem(QObject* parent = 0);
    virtual ~DownloadItem();
 
    QVariant data(int a) const { return m_data.value(a); }
    void setData(int a, QVariant b) { m_data[a] = b; }
 
private:
    QHash<int, QVariant> m_data;
};
 
#endif // DOWNLOADITEM_H

#ifndef DOWNLOADITEM_H
#define DOWNLOADITEM_H

#include <QObject>
#include <QHash>
#include <QVariant>

class DownloadItem : public QObject
{
    Q_OBJECT
public:
    explicit DownloadItem(QObject* parent = 0);
    virtual ~DownloadItem();

    QVariant data(int a) const { return m_data.value(a); }
    void setData(int a, QVariant b) { m_data[a] = b; }

private:
    QHash<int, QVariant> m_data;
};

#endif // DOWNLOADITEM_H

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And if this helps, here a screenshot of the window:
screenshot_ytdownloader.jpg

Any ideas to fix it ?
Is that QHash slow for using data and drawing ?

[wysota]

Calling setData() from within the drawing code is definitely a bad idea. This causes a redraw of the item and your application does nothing but redraws the items over and over again. The model is const in paint() for a reason.