How to create Symbian style list views in Qt - qt

I've never done any item delegates in Qt before, and I think the documentation doesn't explain well about more complex delegates.
I need to create 2 styles of Symbian(^3) style lists
Type 1:
This is for common navigation lists, the icon and the lower label are optional.
Type 2:
This is for settings lists, where the pushbutton can be a toggle(on/off)-button or execute a context menu, etc.
How would I go on creating these sort of item delegates?
Best Regards,
Rat

I had to make something similar once. This is how I did it.
My delegate class declaration. As you can see it has a member: QLabel *label. You can add another label or a pushbutton, depending on your needs.
class MyItemDelegate : public QStyledItemDelegate
{
public:
explicit MyItemDelegate(QObject *parent = 0);
~MyItemDelegate();
protected:
void paint(QPainter *painter,
const QStyleOptionViewItem &option, const QModelIndex &index) const;
QSize sizeHint(const QStyleOptionViewItem &option,
const QModelIndex &index) const;
private:
QLabel *label;
};
My paint() and sizeHint() methods.
QSize MyItemDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const
{
if(!index.isValid())
return QSize();
QVariant data = index.data(Qt::DisplayRole);
label->setText(data.toString());
label->resize(label->sizeHint());
QSize size(option.rect.width(), label->height());
return size;
}
void MyItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
if(!index.isValid())
return;
QVariant data = index.data(Qt::DisplayRole);
// Not necessary to do it here, as it's been already done in sizeHint(), but anyway.
label->setText(data.toString());
painter->save();
QRect rect = option.rect;
// This will draw a label for you. You can draw a pushbutton the same way.
label->render(painter, QPoint(rect.topLeft().x(), rect.center().y() - label->height() / 2),
QRegion(label->rect()), QWidget::RenderFlags());
painter->restore();
}
Hope this is what you've been looking for. Good luck!

You have 2 options ,
1) QML - This in my opinion is the best way to go and easier to achieve what you are trying to do.
Link to Example
This shows you how to use a Delegate for a listview.
2)QItemDelegate - Subclass QItemDelegate then Assign a this delegate to a listview ,
Link to QItemDelegate

Related

Remove CellWidget from QTableWidget when focus out

I have a QTableWidget in which some cells have QComboBox as cellWidget. I want to create the comboBox only when the user clicks in the cell. For this, I have caught itemClicked signal and created the comboBox and set it as cellWidget.
Now, I want to delete this comboBox in two scenarios - if the user selects some value from the comboBox, or the user simply focusses out (click anywhere in the dialog).
For the first case, I have use the signal QComboBox::activated which is invoked when something is selected in the drop-down. There I delete the comboBox and it works fine.
However, I am not sure how to proceed for the second case (delete the comboBox when the user focusses out of the drop-down without selecting anything).
I tried capturing eventFilter for focusOut for the tablewidget as well as the comboBox, but it didn't help.
You can use QItemDelegate for this purpose:
comboboxdelegate.h
class ComboBoxDelegate : public QItemDelegate
{
Q_OBJECT
public:
ComboBoxDelegate(QObject *parent = nullptr) :
QItemDelegate(parent)
{
}
QWidget* createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
QComboBox *editor = new QComboBox(parent);
editor->addItems(QStringList() << "1" << "2" << "3" << "4"); // fill it with your own values
return editor;
}
void setEditorData(QWidget *editor, const QModelIndex &index) const
{
QString text = index.model()->data(index, Qt::EditRole).toString();
QComboBox *cb = static_cast<QComboBox*>(editor);
cb->setCurrentText(text);
}
void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
QComboBox *cb = static_cast<QComboBox*>(editor);
QString text = cb->currentText();
model->setData(index, text, Qt::EditRole);
}
void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
editor->setGeometry(option.rect);
}
};
mainwindow.cpp
...
ui->tableWidget->setItemDelegate(new ComboBoxDelegate);
...

qstyleditemdelegate subclassing paint method not working right

I extended the qstyleditemview class. When I am in the editing mode for the qtreeview item, the paint method seems not to be executing right. When I change state to QStyle::State_Selected it works - it paints the selected row (text) in the qtreeview.
Any idea why it is not working in editing mode?
void myQItemDelegate::paint(QPainter *painter,const QStyleOptionViewItem &option,const QModelIndex &index) const
{
QStyleOptionViewItem s = *qstyleoption_cast<const QStyleOptionViewItem*>(&option);
if(s.state & QStyle::State_Editing)
{
painter->fillRect(s.rect, s.palette.highlight());
s.palette.setColor(QPalette::HighlightedText, QColor(Qt::blue));
}
QStyledItemDelegate::paint(painter, s, index);
}
In the State_Editing state the editor that is a widget created in createEditor() method is opened so that it will not be affected by the QStyleOptionViewItem palette.
Also instead of overwriting the paint method, use the initStyleOption() method:
#include <QtWidgets>
class StyledItemDelegate: public QStyledItemDelegate
{
public:
using QStyledItemDelegate::QStyledItemDelegate;
QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const override {
QWidget * widget = QStyledItemDelegate::createEditor(parent, option, index);
QPalette pal(widget->palette());
pal.setColor(QPalette::HighlightedText, QColor(Qt::blue));
pal.setBrush(QPalette::Highlight, option.palette.highlight());
widget->setPalette(pal);
return widget;
}
protected:
void initStyleOption(QStyleOptionViewItem *option, const QModelIndex &index) const override{
QStyledItemDelegate::initStyleOption(option, index);
option->palette.setColor(QPalette::HighlightedText, QColor(Qt::blue));
}
};
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QTreeView w;
QStandardItemModel model;
w.setModel(&model);
w.setItemDelegate(new StyledItemDelegate);
for(int i=0; i<3; ++i){
auto it = new QStandardItem(QString::number(i));
model.appendRow(it);
for (int j=0; j<4; ++j) {
it->appendRow(new QStandardItem(QString("%1-%2").arg(i).arg(j)));
}
}
w.expandAll();
w.show();
return a.exec();
}
Thanks for helping me out.
I understand now. I added code in QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const metod to style QLineEdit. I am trying to get the same background color for QLineEdit when it is created- when I am editing qtreeview item. The problem is when I select the item in qtreeview the whole row gets colored. That's ok. Now when I edit the item for example to change the text in qtreeview item, only the text part gets selected and colored with the same color as previous row selection color. The rest of the QLineEdit is white. In editing mode I would like to color the whole row which is edited with the same color. I could as obviously from my code color it with RGB but I don't know the exact RGB values. Is there any way to get the exact RGB color from item selection and then use it in
pal.setColor(QPalette::Highlight,QColor(qRgb(0,0,255)));
my code:
QWidget* myQItemDelegate::createEditor(QWidget *parent,const QStyleOptionViewItem &option,const QModelIndex &index) const
{
QLineEdit *lineEdit = new QLineEdit(parent);
connect(lineEdit,SIGNAL(editingFinished()),this,SLOT(commitAndCloseEditor()));
QPalette pal;
pal.setColor(QPalette::HighlightedText, QColor(Qt::white));
pal.setColor(QPalette::Highlight,QColor(qRgb(0,0,255)));
lineEdit->setPalette(pal);
lineEdit->setFrame(false);
return lineEdit;
}
Thanks, Tom

QTableWidget with automatic restore of old cell value

I'm just getting started with QT, so please exercise a little patience...
I've an editable QTableWidget (actually a subclassing), and need to implement the following behavior.
When the user types a non acceptable value I would like:
1) to restore the original value;
2) to keep the focus in the cell and set it in edit mode.
I'm currently using the itemChanged SIGNAL, and a subclassing of QTableWidgetItem.
Which one is the best way to get what I need?
Any tip, suggestion or reference is really welcome.
If you think it as useful I can post some code.
Ciao
Alf.
I'm currently using the itemChanged SIGNAL...
You should subclass QStyledItemDelegate
class CustomTableDelegate : public QStyledItemDelegate
{
Q_OBJECT
public:
CustomTableDelegate (QObject * parent = 0);
QWidget * createEditor (QWidget *, const QStyleOptionViewItem &, const QModelIndex &) const;
bool editorEvent (QEvent *, QAbstractItemModel *, const QStyleOptionViewItem &, const QModelIndex &);
void setEditorData (QWidget *, const QModelIndex &) const;
void setModelData (QWidget *, QAbstractItemModel *, const QModelIndex &) const;
};
And implement validation inside setModelData.
To use custom delegate you need set it for your QTableWidget:
table->setItemDelegate (new CustomTableDelegate () );

Correctly implementing QStyledItemDelegate

I have a class (EditorTagManager) that contains a QTreeWidget. During runtime, the tree can contain any number of tag items, all of which are checkable. I'm trying to add horizontal lines between the QTreeWidgetItems in order to make it clear that these tags are unrelated and are meant to be separate from one another (each item is a root-level node).
From my research on the subject, I've figured out the only way to control the appearance of QtreeWidgetItems to any meaningful extent is to subclass QStyledItemDelegate and bind the delegate to the QTreeWidget. It's kind of an abstract concept so I don't fully understand it. Since I’ve never had to subclass a Qt object before, I'm not sure if I’m doing it correctly.
Since the Qt Documentation didn't really explain how to do this, I used the settingsdialog.cpp/.h files from the Clementine 1.0.1 source code as my guide/reference because Clementine's preferences window uses similar separators on its QTreeWidget. I'm trying to reverse-engineer my own solution from Clementine's code, the only problem is Clementine's implementation of this does things I don't need (so I have to figure out what's relevant to my code and what's not). That's what got me up to this point; my code is very similar to the Clementine code (I just changed the delegate class name):
Here is my current delegate header declaration in editortreemanager.h:
class TagListDelegate : public QWidget
{
public:
TagListDelegate(QObject* parent);
void paint(QPainter* painter, const QStyleOptionViewItem& option,
const QModelIndex& index) const;
};
Here is my current delegate source in editortreemanager.cpp:
TagListDelegate::TagListDelegate(QObject *parent) :
TagListDelegate(parent){
}
void TagListDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
const QModelIndex &index) const{
}
Even though TagListDelegate::paint() doesn't actually do anything yet, I just want to get this code working correctly before I try to change the appearance of the QTreeWidgetItems. My goal is to keep this as simple as possible for now.
Everything compiled fine until I told the QTreeWidget (ui->AvailableTags) to use the delegate:
ui->AvailableTags->setItemDelegate(new TagListDelegate(this));
The compiler error reads:
/home/will/qt_projects/robojournal/ui/editortagmanager.cpp:211: error:
no matching function for call to
'QTreeWidget::setItemDelegate(TagListDelegate*)'
I’m in a bit over my head here so I would definitely appreciate some help in figuring this out.
UPDATE (7/30/13):
My Delegate class now looks like this:
Source:
TagListDelegate::TagListDelegate(QStyledItemDelegate *parent) :
TagListDelegate(parent){
}
void TagListDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
const QModelIndex &index) const{
QStyledItemDelegate::paint(painter, option, index);
}
Header declaration:
class TagListDelegate : public QStyledItemDelegate
{
public:
TagListDelegate(QStyledItemDelegate* parent);
void paint(QPainter* painter, const QStyleOptionViewItem& option,
const QModelIndex& index) const;
};
UPDATE (7/31/13)
Here is what my classes look like now:
header:
class TagListDelegate : public QStyledItemDelegate
{
public:
TagListDelegate(QObject* parent);
QSize sizeHint(const QStyleOptionViewItem& option, const QModelIndex& index) const;
void paint(QPainter* painter, const QStyleOptionViewItem& option,
const QModelIndex& index) const;
};
source:
TagListDelegate::TagListDelegate(QObject *parent)
: TagListDelegate(parent){
}
QSize TagListDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const
{
QSize ret = QStyledItemDelegate::sizeHint(option, index);
return ret;
}
void TagListDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
const QModelIndex &index) const{
QStyledItemDelegate::paint(painter, option, index);
}
You're not subclassing QStyledItemDelegate in your code. You're subclassing QWidget.
Change
class TagListDelegate : public QWidget
to:
class TagListDelegate : public QStyledItemDelegate
And don't forget to include the header:
#include <QStyledItemDelegate>

How to check whether the tree view's item is expanded in delegate?

I'm developing a Qt application and I want to know whether the tree view's item is expanded in delegate function.
Here is my tree view's delegate..
void roster_item_delegate::paint(QPainter *painter,
const QStyleOptionViewItem &option,
const QModelIndex &index) const
{
/* How can I know whether this item is expanded or not in here? */
}
I think it's possible using the tree view's pointer and isExpanded() function, but I don't know how can I obtain the pointer in delegate function.
Thank you.
you can use the option parameter to check of the given item is expanded; below is an example:
void MyItemDelegate::paint(QPainter* painter, const QStyleOptionViewItem & option, const QModelIndex &index) const
{
QStyle::State state = option.state;
if ((state & QStyle::State_Open) > 0)
qDebug() << index.data(0) << " item is expanded";
QStyledItemDelegate::paint(painter, option, index);
}
hope this helps, regards

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