Creating a custom widget to advance in Qt design

Question

I am developing a GUI application in Qt and I have some difficulties embedding a custom widget in my ui. From the Qt documentation, I see that you can promote such a widget. However, I am still a little confused about how this should be done.

My QTreeWidget widget is heavily inspired by the Qt torrent example , where I want to embed it in my application:

So, I have a FilesView class (src code is not included because it is trivial):

#include <QTreeWidget> #include <QUrl> #include <QFile> #include <QDragMoveEvent> #include <QDropEvent> // FilesView extends QTreeWidget to allow drag and drop. class FilesView : public QTreeWidget { Q_OBJECT public: FilesView(QWidget *parent = 0); signals: void fileDropped(const QString &fileName); protected: void dragMoveEvent(QDragMoveEvent *event); void dropEvent(QDropEvent *event); }; 

This is the TorrentViewDelegate class (comment on the progress bar for testing purposes)

 #include <QItemDelegate> #include <QMainWindow> #include <QApplication> // TorrentViewDelegate is used to draw the progress bars. class TorrentViewDelegate : public QItemDelegate { Q_OBJECT public: inline TorrentViewDelegate(QMainWindow *mainWindow) : QItemDelegate(mainWindow) {} inline void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index ) const { if (index.column() != 2) { QItemDelegate::paint(painter, option, index); return; } // Set up a QStyleOptionProgressBar to precisely mimic the // environment of a progress bar. QStyleOptionProgressBar progressBarOption; progressBarOption.state = QStyle::State_Enabled; progressBarOption.direction = QApplication::layoutDirection(); progressBarOption.rect = option.rect; progressBarOption.fontMetrics = QApplication::fontMetrics(); progressBarOption.minimum = 0; progressBarOption.maximum = 100; progressBarOption.textAlignment = Qt::AlignCenter; progressBarOption.textVisible = true; // Set the progress and text values of the style option. //int progress = qobject_cast<MainWindow *>(parent())->clientForRow(index.row())->progress(); int progress = 40; progressBarOption.progress = progress < 0 ? 0 : progress; progressBarOption.text = QString().sprintf("%d%%", progressBarOption.progress); // Draw the progress bar onto the view. QApplication::style()->drawControl(QStyle::CE_ProgressBar, &progressBarOption, painter); } }; 

In the example, insert the widget into MainWindow as:

 filesView = new FilesView(this); filesView->setItemDelegate(new TorrentViewDelegate(this)); filesView->setHeaderLabels(headers); filesView->setSelectionBehavior(QAbstractItemView::SelectRows); filesView->setAlternatingRowColors(true); filesView->setRootIsDecorated(false); ui->verticalLayout_Filebox->addWidget(filesView); 

How can I do this from a Qt designer?

Answer 1

• Place an empty widget, where you want to have FilesView
• Right click on it and select Promote
• Name the advanced class FilesView click Add , and then Promote
• You cannot set a delegate from QtDesigner

For more information see here:

http://qt-project.org/doc/qt-4.8/designer-using-custom-widgets.html

The second option that you have is to create a plugin for your widget that allows you to set its properties through the constructor. If you are not going to use your widget several times, I do not offer it. For more information check the following link:

http://qt-project.org/doc/qt-4.8/designer-creating-custom-widgets.html