We are using a QTableView with a custom QAbstractTableModel. Some data is too long to display in the cells directly or we would like to show additional information.
In the model we use the following code:
QVariant MyTableModel::data(const QModelIndex &index, int role) const
{
if (role == Qt::DisplayRole) {
return "Short Content";
}
if (role == Qt::ToolTipRole) {
return "Super long content which contains line\nbreaks, tabs\t and more.";
}
return QVariant();
}
This works and when hovering the cells the tooltip is displayed. However, this takes a few seconds for the tooltip to appear and sometimes some mouse-wiggling.
Is there a built-in way in Qt 5 to disable the timeout and always display the tooltip?
As they point out in the Qt forum the delay depends on the style and is returned through SH_ToolTip_WakeUpDelay which is 700 ms by default.
Considering the above, a possible solution is to use the QProxyStyle method override:
class ProxyStyle : public QProxyStyle
{
public:
using QProxyStyle::QProxyStyle;
int styleHint(StyleHint hint, const QStyleOption* option = nullptr, const QWidget* widget = nullptr, QStyleHintReturn* returnData = nullptr) const override
{
if (hint == QStyle::SH_ToolTip_WakeUpDelay)
return 0;
return QProxyStyle::styleHint(hint, option, widget, returnData);
}
};
tableview->setStyle(new ProxyStyle(tableview->style()));
Related
Is it possible to set a QItemDelegate on a particular QTreeWidgetItem? I need to color some of the QTreeWidgetItems with a particular color.
I assume it is possible as we have QAbstractItemView::setItemDelegateForRow but I can't figure out how. I can't use QAbstractItemView::setItemDelegateForRow because I need to set a custom delegate on a child row inside the QTreeWidget.
Does anyone know a solution for that?
You can't use QTreeWidgetItem in delegate directly (probably you can store list of this items inside delegates but I think that it is not efficient), because delegates works with QModelIndex and data inside different roles. You can set data to Qt::UserRole+1 and access it inside delegate. For example:
QTreeWidgetItem *cities = new QTreeWidgetItem(ui->treeWidget);
//...
cities->setData(0,Qt::UserRole+1,"chosen one");
QTreeWidgetItem *osloItem = new QTreeWidgetItem(cities);
//...
QTreeWidgetItem *berlinItem = new QTreeWidgetItem(cities);
//...
berlinItem->setData(0,Qt::UserRole+1,"chosen one");
Inside delegate (just example):
void ItemDelegatePaint::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
QString txt = index.model()->data( index, Qt::DisplayRole ).toString();
if( option.state & QStyle::State_Selected )
{
if(index.data(Qt::UserRole+1).toString() == "chosen one")
painter->fillRect( option.rect,Qt::green );
else
painter->fillRect( option.rect, option.palette.highlight() );
}else
if(option.state & QStyle::State_MouseOver)
{
if(index.data(Qt::UserRole+1).toString() == "chosen one")
painter->fillRect( option.rect,Qt::yellow );
else
painter->fillRect( option.rect, Qt::transparent );
}
else
{
QStyledItemDelegate::paint(painter,option,index);
}
}
You can access the QTreeWidget from you delegate's paint routine to check if a condition for painting the background is met
void custom_delegate::paint(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
const QTreeWidget* tree_widget = qobject_cast<const QTreeWidget*>(qstyleoption_cast<const QStyleOptionViewItemV3*>(&option)->widget);
....
}
or you store something in the QModelIndex UserData as Chernobyl suggested. In that case I would however create an enum for flags (if this is applicable in your case):
enum custom_painter_flags{
paint_default = 0,
paint_background = 1
};
void somewhere_creating_the_items()
{
QTreeWidgetItem* newitem = new QTreeWidgetItem(...);
newitem->setData(0, Qt::UserRole, QVariant::fromValue<int>(custom_painter_flags::paint_background));
}
void custom_delegate::paint(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
custom_painter_flags painter_flags = static_cast<painter>(index.data(Qt::UserRole).value<int>());
if(painter_flags & paint_background){
....
}
}
Unfortunately I have not much time right now so this is thrown together pretty quick. Feel free to edit if you find any errors.
You can use qss on the QTreeWidgetItem to change color or background color.
I have done it for a QTableWidget, You must check the value of all your QTreeWidgetItem and set a background color / color.
For example, for my QTableWidget i have done something like this in a loop :
if(good item):
MyQTableItem.setBackground(QtGui.QColor(255,255,255))
Can I extend QFileSystemModel and add new column with text / icon?
Regards
I would start by subclassing the model, providing the additional column and supplying the data to it.
So at the very least I would reimplement columnCount() and data() in both cases calling the base class and manipulating the results accordingly.
class yourSystemModel : public QFileSystemModel
{
Q_OBJECT
int columnCount(const QModelIndex& parent = QModelIndex()) const
{
return QFileSystemModel::columnCount()+1;
}
QVariant data(const QModelIndex& index,int role) const
{
if(!index.isValid()){return QFileSystemModel::data(index,role);}
if(index.column()==columnCount()-1)
{
switch(role)
{
case(Qt::DisplayRole):
{return QString("YourText");}
case(Qt::TextAlignmentRole):
{return Qt::AlignHCenter}
default:{}
}
}
return QFileSystemModel::data(index,role);
}
}
The official doc outline some basis as to minimal reimplementation for the abstract item model, but in this case you can run away with much less.
http://doc.qt.digia.com/stable/qabstractitemmodel.html - Subclassing section.
Could you please let me know how to chage the position of the item in QTreeView.By default the item displayed at Left most and in the center of the item box.But how should i change it so that it will display in top
Using a Qt built-in item model
If you are using e.g. QFileSystemModel you have to inherit from it and override the data() behaviour:
class MyFileSystemModel : public QFileSystemModel {
public:
QVariant data(const QModelIndex & index, int role = Qt::DisplayRole) const {
if (role == Qt::TextAlignmentRole)
return Qt::AlignTop; //maybe different result depending on column/row
else
return QFileSystemModel::data(index, role);
}
and then use that class instead.
Using own item model
If you implemented your own item model all you have to do is handle Qt::TextAlignmentRole in data():
QVariant MyTreeModel::data (const QModelIndex &index, int role) const {
if (role == Qt::TextAlignmentRole)
return Qt::AlignTop; //maybe different result depending on column/row
//handle other roles
return QVariant();
}
The tree view should now automatically align the items to the top.
If you want to customize the appearance even further, here are the roles that are used by QTreeView. For more customization I think you have to implement your own QTreeView subclass.
Using QStandardItemModel
If you did not implement your own model but used QStandardItemModel you have to call
setTextAlignment(Qt::Alignment alignment) with Qt::AlignTop on your standard items before adding them to the model.
I have a QTableView which has some QString based items in its model. I implemented setData in my table model, so editing is working (I can change the data in the cell, setData is called to update the model, and the table is properly updated).
Currently setData is only called when the user is done with editing, e.g. after they hit Enter or click out of the text entry box to finalize the text entry. I want to update other other parts of the table while the user is typing/editing into the text edit control instead of after they're done and the edited contents are finalized.
A simple example of what I want to have is for the next table cell to display a count of how many characters have been entered into the cell being edited, but to do this as the user is typing/editing the cell contents, not just after the edit is finalized and setData is called.
Any pointers to what I should be looking for? Thanks!
You can subclass QStyledItemDelegate and commit the data whenever something changes, and then set that delegate for the view with QAbstractItemView::setItemDelegate.
class MyDelegate : public QStyledItemDelegate {
QSignalMapper *mapper;
public:
MyDelegate(QObject*parent = 0)
: QStyledItemDelegate(parent)
, mapper(new QSignalMapper(this))
{
connect(mapper, SIGNAL(mapped(QWidget*)), SIGNAL(commitData(QWidget*)));
}
QWidget * createEditor(QWidget * parent, const QStyleOptionViewItem & option,
const QModelIndex & index ) const
{
QWidget *editor = QStyledItemDelegate::createEditor(parent, option, index);
if(qobject_cast<QLineEdit*>(editor)) {
connect(editor, SIGNAL(textChanged(QString)), mapper, SLOT(map()));
mapper->setMapping(editor, editor);
}
return editor;
}
};
The answer offered by #alexisdm did not work for me when I needed a persistent
editor enabled by QAbstractTableModel::setPersistentEditor(QModelIndex()).
The following solves this problem:
class Delegate : public QStyledItemDelegate
{
Q_OBJECT
public:
// ... omitted for brevity
QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option,
const QModelIndex &index) const override
{
auto *editor = static_cast<QLineEdit*>(
QStyledItemDelegate::createEditor(parent, option, index));
if (editor) {
connect(editor,
&QLineEdit::textChanged,
[=] (const QString &)
{
const_cast<Delegate*>(this)->commitData(editor);
});
}
return editor;
}
// ... omitted for brevity
};
We simply cast the constness from this and make it commit data for the editor.
Note that in the lambda we capture the editor variable by value [=] because otherwise, capturing with reference would make the value of editor undefined when the function runs out of scope.
Is there any way to determine if a QTableView has an open editor in the current cell? I need to handle the following situation:
A user double-clicks a cell and edits the data, but leaves the cell in the "edit" state.
On another part of the UI, an action is taken that changes the selected row of the underlying model.
Back on my view, I want to determine if the newly selected row is the same as the open row. If not, I need to take an action. (Prompt the user? Commit automatically? Revert?)
I see how to get the current item, and can get the delegate on that item, but I don't see any isEditMode() property I was hoping to find.
Can someone point me in the right direction?
Just check whether the return value of
State QAbstractItemView::state () const
is
QTableView::EditingState
Connect to underlying model dataChanged signal
void QAbstractItemModel::dataChanged ( const QModelIndex & topLeft, const QModelIndex & bottomRight )
You can check if the cell where data has changed is the same than the currentIndex
QModelIndex QAbstractItemView::currentIndex () const
You cannot know if the current cell had an open editor straight, but can check if the view is in QAbstractItemView::EditingState
State QAbstractItemView::state () const
It should be enough to do what you want.
You can subclass QTableView in order to be able to access the state() function, which is unfortunately protected. However, I did not try that.
If you already have an QStyledItemDelegate subclass, you can use it to track whether an editor is currently open. However, you can't just use setEditorData/setModelData, because setModelData won't be called, when the user cancels editing. Instead, you can track the creation and destruction of the editor itself.
class MyItemDelegate : public QStyledItemDelegate
{
Q_OBJECT
public:
MyItemDelegate( QObject* parent = nullptr );
~MyItemDelegate();
QWidget* createEditor( QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index ) const;
void setEditorData( QWidget* editor, const QModelIndex& index ) const;
void setModelData( QWidget* editor, QAbstractItemModel* model, const QModelIndex& index ) const;
bool isEditorOpen() const { return *m_editorCount > 0; }
protected:
int* m_editorCount;
protected slots:
void onEditorDestroyed( QObject* obj );
};
Implementation:
MyItemDelegate::MyItemDelegate( QObject* parent ) :
QStyledItemDelegate( parent )
{
m_editorCount = new int;
*m_editorCount = 0;
}
MyItemDelegate::~MyItemDelegate()
{
delete m_editorCount;
}
QWidget* MyItemDelegate::createEditor( QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index ) const
{
// create an editor, can be changed as needed
QWidget* editor = QStyledItemDelegate::createEditor( parent, option, index );
connect( editor, SIGNAL(destroyed(QObject*)), SLOT(onEditorDestroyed(QObject*)));
printf( "editor %p created\n", (void*) editor );
(*m_editorCount)++;
return editor;
}
void MyItemDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
{
...
}
void MyItemDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
...
}
void MyItemDelegate::onEditorDestroyed( QObject* obj )
{
printf( "editor %p destroyed\n", (void*) obj );
(*m_editorCount)--;
}
On some occasions, e.g. when moving to the next item in the tree using the cursor keys, Qt will create the new editor first and then destroy the old one. Hence, m_editorCount must be an integer instead of a bool.
Unfortunately, createEditor() is a const function. Therefore, you cannot create an int-member. Instead, create a pointer to an int and use that.
Subclass your delegate so that it includes an accessor that tells you when it's editing:
void MyDelegate::setEditorData ( QWidget * editor, const QModelIndex & index ) const {
// _isEditing will have to be mutable because this method is const
_isEditing = true;
QStyledItemDelegate::setEditorData(editor, index);
}
void MyDelegate::setModelData ( QWidget * editor, QAbstractItemModel * model, const QModelIndex & index ) const {
QStyledItemDelegate::setModelData(editor, model, index);
_isEditing = false;
}
bool MyDelegate::isEditing() const { return _isEditing; }
Then you can just check the delegate to see what's going on. Alternatively and/or if you don't like the mutable, you can emit signals so you know what state the delegate is in.
If you know the index of the item being edited, you can call indexWidget() and attempt to cast it. If it's valid, you not only know you're editing, but you also have your editor widget handy.
EditWidget *editWidget = qobject_cast<EditWidget*>(tableView->indexWidget(tableView->currentIndex()));
if(editWidget)
{
//yep, ur editing bro
}
Here is an idea, its even helpful to get the edit/combo widget before the edit begins...
just emit a signal and consume it in the mainwindow... this is what I used one to get combo box in QTableWidget before editing...
first create a signal in ComoBoxItemDelegate...
signals:
void OnComboEdit(QComboBox* pCombo) const;
then emit the signal in the createEditor method...
QWidget* ComboBoxItemDelegate::createEditor(QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
// Create the combobox and populate it
QComboBox* cb = new QComboBox(parent);
emit OnComboEdit(cb);
return cb;
}
and in the MainWindow declare a function to receive the singal...
void MainWindow::OnComboEidt(QComboBox *pCB) const
{
qDebug() << "Combo Eidt Singal Received";
}
Then finally in the constructor of MainWindow connect it...
ComboBoxItemDelegate* cbid = new ComboBoxItemDelegate(ui->tableWidget);
connect(cbid, &ComboBoxItemDelegate::OnComboEdit, this, &MainWindow::OnComboEidt);
ui->tableWidget->setItemDelegateForColumn(0, cbid);