add custom widget to QTableWidget cell - qt

I have custom widget made with qt designer and i want to add it to QTableWidget cell.
But it doesn't work.
Here is the code :
int nRows =10;
for(int row = 0; row < nRows;row++;)
{
QTableWidgetItem* item = new QTableWidgetItem();
CustomWdg* wdg=new CustomWdg( );
mTableWdg->insertRow( row );
mTableWdg->setItem(row, 0, item);
mTableWdg->setCellWidget( row, 0, wdg );
}

If you want to add custom widget into table cell you can use QItemDelegate.
Create your own Delegate class and inherit it from QItemDelegate.
class MyDelegate : public QItemDelegate
{
public:
CChoicePathDelegate (QObject *parent = 0);
QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const; //delegate editor (your custom widget)
void setEditorData(QWidget *editor, const QModelIndex &index) const;
void setModelData(QWidget *editor, QAbstractItemModel *model,
const QModelIndex &index) const; //transfer editor data to model
void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option,
const QModelIndex &index) const;
};
And then set delegate for Table with this methods on your own.
setItemDelegate(QAbstractItemDelegate *)
setItemDelegateForColumn(int, QAbstractItemDelegate *)
setItemDelegateForRow(int, QAbstractItemDelegate *)
I have tried this code:
#include "widget.h"
#include "ui_widget.h"
#include <QPushButton>
#include <QLabel>
#include <QHBoxLayout>
Widget::Widget(QWidget *parent) :
QWidget(parent),
ui(new Ui::Widget)
{
ui->setupUi(this);
QHBoxLayout *l = new QHBoxLayout();
l->addWidget((new QPushButton("I`m in cell")));
l->addWidget((new QLabel("Test label")));
QWidget *w = new QWidget();
w->setLayout(l);
ui->tableWidget->setCellWidget(1,1, w);
}
Widget::~Widget()
{
delete ui;
}
and result is:

Your code is correct, so the only thing that comes to my mind is that you didn't setColumnCount(1) before for loop. If that's not the case, you could try to set row and column count before that for loop instead inserting row by row in loop:
int nRows =10;
mTableWdg->setRowCount(nRows);
mTableWdg->setColumnCount(1);
for(int row = 0; row < nRows;row++;)
{
//QTableWidgetItem* item = new QTableWidgetItem();// line one
CustomWdg* wdg=new CustomWdg( );
//mTableWdg->setItem(row, 0, item);// line three
mTableWdg->setCellWidget( row, 0, wdg );
}
If you really need item ("line one" and "line three") you should set it like this: QTableWidgetItem* item = new QTableWidgetItem("");, otherwise you don't need those lines, your CustomWdg is properly set with setCellWidget

Related

Resizing a QTableView column horizontally to the content of an item delegated column which is painted with a new text in Qt

I want to show my database tabel content in a QTableView. I use the following codes to do that:
QSqlDatabase test = QSqlDatabase::addDatabase("QMYSQL");
test.setDatabaseName("dbText");
test.setHostName("localhost");
test.setUserName("***");
test.setPassword("***");
if (!test.open())
qDebug()<<"ERROR ";
QSqlTableModel *model = new QSqlTableModel(this,test);
model->setTable("textTable");
model->setEditStrategy(QSqlTableModel::OnManualSubmit);
model->select();
ui->tableView->horizontalHeader()->setSectionResizeMode(QHeaderView::ResizeToContents);
ui->tableView->setModel(model);
ui->tableView->show();
As it is depicted in the following picture, ui->tableView columns are resized to the content of the database table columns.
Now, I want to clear the display text of Description column and paint it with new text and color. For this propose, I have used the function QTableView::setItemDelegateForColumn as follow:
ui->tableView->setItemDelegateForColumn(2,new PowerColorDelegate(this));
And here are PowerColorDelegate header and source file content:
PowerColorDelegate.h
#include <QStyledItemDelegate>
class PowerColorDelegate : public QStyledItemDelegate
{
Q_OBJECT
public:
PowerColorDelegate(QObject *parent = 0);
protected:
void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const;
QString displayText(const QVariant &value, const QLocale &locale) const;
};
PowerColorDelegate.cpp
#include <QApplication>
#include <QPainter>
#include "powercolordelegate.h"
PowerColorDelegate::PowerColorDelegate(QObject *parent) : QStyledItemDelegate(parent)
{
}
void PowerColorDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
QStyleOptionViewItem opt = option;
initStyleOption(&opt, index);
if(!index.isValid())
{
QStyledItemDelegate::paint(painter, option, index);
return;
}
// Position our pixmap
const int x = option.rect.left();
const int y = option.rect.top();
QString newColor = "#fcaf9e";
QString newText = "This is my new text which I want to paint!";
painter->fillRect(option.rect, newColor);
painter->drawText(QRect(x, y, 80, 20), newText);
QStyledItemDelegate::paint(painter, opt, index);
}
QString PowerColorDelegate::displayText(const QVariant &value, const QLocale &locale) const
{
return "";
}
The result of using PowerColorDelegate on ui->tableView is shown in this picture:
How can I resize the third ui->tableView column (Description) horizontally to the content of the painted column?
Implement sizeHint for your delegate according to required text format

How to remove QTreeView indentation

I want to have a QTreeView without an indentation on the left side increasing at each nesting level. I tried setting QTreeView::setIndentation(0). It removes the indentations just as I want, however it also hides the tree arrows.
Default behavior:
With indentations ✗
With arrows ✔
After setIndentation(0):
Without indentations ✔
Without arrows ✗
Desired behavior:
Without indentations ✔
With arrows ✔
So how can I achieve the result shown in the third example? Is there any standard way of doing it, or I will have to reimplement the QTreeView::paintEvent(), QTreeView::drawBranches(), etc.?
To solve the problem I used a delegate to translate the paint of the items, and paint the arrows.
#include <QtWidgets>
class BranchDelegate: public QStyledItemDelegate
{
public:
using QStyledItemDelegate::QStyledItemDelegate;
void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const override{
QStyleOptionViewItem opt(option);
if(index.column() == 0)
opt.rect.adjust(opt.rect.height(), 0, 0, 0);
QStyledItemDelegate::paint(painter, opt, index);
if(index.column() == 0){
QStyleOptionViewItem branch;
branch.rect = QRect(0, opt.rect.y(), opt.rect.height(), opt.rect.height());
branch.state = option.state;
const QWidget *widget = option.widget;
QStyle *style = widget ? widget->style() : QApplication::style();
style->drawPrimitive(QStyle::PE_IndicatorBranch, &branch, painter, widget);
}
}
};
class TreeView: public QTreeView
{
public:
TreeView(QWidget *parent=nullptr):QTreeView(parent)
{
BranchDelegate *delegate = new BranchDelegate(this);
setItemDelegate(delegate);
setIndentation(0);
}
protected:
void mousePressEvent(QMouseEvent *event) override{
QModelIndex index = indexAt(event->pos());
bool last_state = isExpanded(index);
QTreeView::mousePressEvent(event);
if(index.isValid() && last_state == isExpanded(index))
setExpanded(index, !last_state);
}
};
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
TreeView w;
QFileSystemModel model;
model.setRootPath(QDir::rootPath());
w.setModel(&model);
w.setRootIndex(model.index(QDir::homePath()));
/*for (int i = 1; i< model.columnCount() ; ++i) {
w.hideColumn(i);
}*/
w.expandAll();
w.resize(640, 480);
w.show();
return a.exec();
}
eyllanesc's falls appart if there is horizontal scrolling. Also usually the view only expands/collapses when clicking the branch-indicator, not the index.
My Solution: Only change the Rect of indices which have a parent but no children. Also dont set the indentation to 0. No need to subclass QTreeView.
#include <QtWidgets>
class BranchDelegate: public QStyledItemDelegate
{
public:
mIndent = 50;
using QStyledItemDelegate::QStyledItemDelegate;
void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const override
{
QStyleOptionViewItem opt(option);
if(index.parent().isValid && (!index.model() || !index.model()->index(0, 0, index).isValid()))
{
opt.rect.adjust(-mIndent, 0, 0, 0);
}
QStyledItemDelegate::paint(painter, opt, index);
}
};
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QTreeView apView;
BranchDelegate* const apDelegate = new BranchDelegate(apView);
apDelegate->mIndent = 50;
apView->setIndentation(apDelegate->mIndent);
apView->setItemDelegateForColumn(0, apDelegate);
QFileSystemModel model;
model.setRootPath(QDir::rootPath());
apView.setModel(&model);
apView.setRootIndex(model.index(QDir::homePath()));
/*for (int i = 1; i< model.columnCount() ; ++i) {
apView.hideColumn(i);
}*/
apView.expandAll();
apView.resize(640, 480);
apView.show();
return a.exec();
}
ellyanesc's answer works, but is incorrect by one small detail in the line:
branch.rect = QRect(0, opt.rect.y(), opt.rect.height(), opt.rect.height());
The reason is because when the view is horizontally scrolled, option.rect.x() becomes negative. If branch.rect.x() is 0 (as in ellyanesc's answer), the branch indicator will always be shown, which also causes artifacts during scroll:
https://i.stack.imgur.com/O518A.png
https://i.stack.imgur.com/qYJMj.png
To solve this, replace the above line with:
branch.rect = QRect(option.rect.x(), opt.rect.y(), opt.rect.height(), opt.rect.height());
(I would have just pointed that out as a comment in ellyanesc's answer, but I don't have enough reputation for that.)

QStyledItemDelegate custom widget drawn incorrect, when scrolling

One of my earlier Question deals with a customized QStyledItemDelegate containing a QWidget with two QLabels side by side.
I was really satisfied with the easy solution given by Joseph Ireland. Unfortunately, the given is solution is broken, but I didn't realized this immediately. If the QTableWidget containing my QStyledItemDelegate gets too small, the scrollbars are activated.
Now scrolling destroys the correct drawing of my cell elements. This seems to be some kind of update problem. I realized this, after I draw a rectangle around the viewport region of my QAbstractScollArea.
My table looks like the following, if you will scroll violently:
Cells contents are not drawn at the right place or seemingly not draw after all. Happens strangely for every second row. Even more the rectangle drawn around the viewport region of my QAbstractScrollArea is messed up. If the window is redrawn (hide/show window) everything is fine.
What might the solution to this kind of update/repaint problem? Maybe I need to repaint after scrolling is finished?
My adapted solution posted by Joseph Ireland was:
Header-File: TwoNumbersDelegate.h
#pragma once
#include <QStyledItemDelegate>
class QLabel;
class TwoNumbersDelegate : public QStyledItemDelegate {
public:
TwoNumbersDelegate(QObject* parent = nullptr);
virtual void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const override;
virtual QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const override;
private:
QLabel* mLeft;
QLabel* mRight;
QFrame* mFrame;
};
Source File: TwoNumbersDelegate.cpp
#include "TwoNumbersDelegate.h"
#include <QLabel>
#include <QPainter>
#include <QDebug>
#include <QHBoxLayout>
#include <QTableWidget>
TwoNumbersDelegate::TwoNumbersDelegate(QObject* parent /*= nullptr*/) : QStyledItemDelegate(parent)
{
mLeft = new QLabel("%1");
mRight = new QLabel("%2");
mFrame = new QFrame;
mFrame->setLayout(new QHBoxLayout);
mFrame->layout()->addWidget(mLeft);
// you could add a spacer here maybe
mFrame->layout()->addWidget(mRight);
mFrame->setAttribute(Qt::WA_DontShowOnScreen, true);
mFrame->show();
}
void TwoNumbersDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
auto data = index.data(Qt::EditRole);
auto list = data.toList();
if (list.size() != 2) {
QStyledItemDelegate::paint(painter, option, index);
}
mLeft->setText(list.at(0).toString());
mRight->setText(list.at(1).toString());
mFrame->resize(option.rect.size());
qDebug() << option.rect.size();
// mFrame->layout()->invalidate();
// mFrame->layout()->activate();
if (auto tableWidget = qobject_cast<QTableWidget*>(parent())) {
auto cellRegion = QRegion(option.rect);
auto viewportRegion = QRegion(tableWidget->viewport()->rect());
auto intersectedRegion = cellRegion.intersected(viewportRegion);
intersectedRegion.translate(-option.rect.topLeft());
painter->drawRect(tableWidget->viewport()->rect().adjusted(0,0,-1,-1));
painter->save();
painter->translate(option.rect.topLeft());
mFrame->render(painter, QPoint(), intersectedRegion, QWidget::DrawChildren);
qDebug() << cellRegion << viewportRegion << intersectedRegion;
painter->restore();
}
}
QSize TwoNumbersDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const
{
return mFrame->minimumSizeHint();
}
The following program served me as a test runner:
#include <QApplication>
#include <QTableWidget>
#include <QVBoxLayout>
#include "TwoNumbersDelegate.h"
int main(int argc, char** args) {
QApplication q(argc, args);
auto frame = new QFrame;
frame->setLayout(new QVBoxLayout);
//frame->setStyleSheet("QFrame { background: green}"); // Activate this to see overdrawing
auto table = new QTableWidget;
table->setAlternatingRowColors(true);
table->setItemDelegate(new TwoNumbersDelegate);
table->setRowCount(20);
table->setColumnCount(10);
for (auto iter = 0; iter < 20; iter++) {
for (auto colIter = 0; colIter < 10; colIter++) {
auto item = new QTableWidgetItem;
QVariantList map;
map << iter << iter*colIter;
item->setData(Qt::EditRole, map);
table->setItem(iter, colIter, item);
}
}
frame->layout()->addWidget(table);
frame->show();
q.exec();
}

Access pointer to QWidget(Combobox) of the customdelegate

I have derived a class from QStyledItemDelegate. I am using a QComboBox in this delegate. This delegate is used in QTableView.
My question is, how can i change the index of the Combobox in the delegate programatically i.e how to access the pointer to that widget outside the delegate class ?
I have checked that CreateEditor, SetEditorData, SetModelData functions (of QStyledItemDelegate) are called automatically when we click on the combobox and we cannot call them manually to maniplate the data in the model.
afaik any time you start editing and the combobox is shown, it will allocate a new one. if you want to have a permanent combobox, you should look at
QTableView::setIndexWidget(const QModelIndex&, QWidget*)
so you could access the combobox with the following code:
const QMoodelIndex idx = model->index(row, column);
QWidget* wid = view->indexWidget(idx);
QComboBox* box = qobject_cast<QComboBox*>(wid);
if (box)
// do your thing
You can have the contents of your combobox as a class member of your delegate in a QStringList. Your item delegate can be like :
#include <QStyledItemDelegate>
#include <QComboBox>
class ComboBoxDelegate: public QStyledItemDelegate
{
Q_OBJECT
public:
ComboBoxDelegate(QObject *parent = 0);
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;
void updateEditorGeometry( QWidget *editor,
const QStyleOptionViewItem &option,
const QModelIndex &index ) const;
QStringList comboItems;
mutable QComboBox *combo;
private slots:
void setData(int val);
};
ComboBoxDelegate::ComboBoxDelegate(QObject *parent ):QStyledItemDelegate(parent)
{
}
QWidget *ComboBoxDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
combo = new QComboBox( parent );
QObject::connect(combo,SIGNAL(currentIndexChanged(int)),this,SLOT(setData(int)));
combo->addItems(comboItems);
combo->setMaxVisibleItems(comboItems.count());
return combo;
}
void ComboBoxDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
{
QString text = index.model()->data( index, Qt::DisplayRole ).toString();
int comboIndex = comboItems.indexOf(QRegExp(text));
if(comboIndex>=0)
(static_cast<QComboBox*>( editor ))->setCurrentIndex(comboIndex);
}
void ComboBoxDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
model->setData( index, static_cast<QComboBox*>( editor )->currentText() );
}
void ComboBoxDelegate::updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
editor->setGeometry( option.rect );
}
void ComboBoxDelegate::setData(int val)
{
emit commitData(combo);
//emit closeEditor(combo);
}
When you want to update the items in combobox somewhere in your code just get a pointer to the item delegate by calling itemDelegateForColumn and access the comboItems member :
ComboBoxDelegate * itemDelegate = qobject_cast<ComboBoxDelegate *>(ui->tableView->itemDelegateForColumn(columnIndex));
//Updating combobox items
itemDelegate->comboItems.append("newItem");
...

Qt Model View for a given populated ro QList

i got a godgiven list of xyz (the code says int, just an example) glued into a QList (to big to move anywhere). How can I create a Model View for that? I allready read the Qt doc which tells me, I have to reimplement data, index, parent, rowCount, columnCount functions. But the preprocessor/compiler cries for more reimplemented functions? I allready read a chapter in my Qt Book but it did not help either. Here my hacked away code:
class XModel : public QAbstractListModel
{
Q_OBJECT
public:
explicit XModel(QList<int> *valuelist, QObject *parent = 0);
virtual ~XModel();
int rowCount(const QModelIndex &) const;
int columnCount(const QModelIndex &) const;
QModelIndex index( int row, int column, const QModelIndex & parent = QModelIndex()) const;
QModelIndex parent(const QModelIndex &index) const;
QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;
private:
QList<int>* blah;
signals:
public slots:
};
XModel::XModel(QList<int> *valuelist, QObject *parent) :
QAbstractListModel(parent),
blah(valuelist)
{
}
XModel::~XModel()
{
}
int XModel::rowCount(const QModelIndex &) const
{
return blah->size();
}
int XModel::columnCount(const QModelIndex &) const
{
return 1;
}
QModelIndex XModel::index(int row, int column, const QModelIndex &parent) const
{
return createIndex(row, column, (void)&(blah->at(row)));
}
QModelIndex XModel::parent(const QModelIndex &index) const
{
return createIndex(index->row(), index->column(), NULL);
}
QVariant XModel::data(const QModelIndex &index, int role = Qt::DisplayRole) const
{
return QVariant(blah->at(index.row()));
}
Do I even have to use QAbstractItemModel or does QAbstractListModel work the exact same way? How do I give the Model the source of the actual data? Is this only within data function? Please tell me what I am doing wrong, I do not see it and give advice on howto do it properly, (good) howtos welcome.
This is fixed, but...
EDIT:
Widget::Widget(QWidget *parent)
: QWidget(parent),
valuelist(),
xm(&valuelist) //xm = XModel
{
valuelist.append(1);
valuelist.append(2);
valuelist.append(3);
valuelist.append(4);
valuelist.append(5);
valuelist.append(6);
valuelist.append(7);
valuelist.append(8);
valuelist.append(9);
view = new QListView(this);
view->setModel(&xm);
//how to force the XModel to reread the QList`?
view->show();
}
Add to and remove data from XModel and have XModel modify the underlying list (reference?) for you:
Widget::Widget(QWidget *parent)
: QWidget(parent),
valuelist(),
xm(&valuelist) //xm = XModel
{
xm.append(1);
xm.append(2);
xm.append(3);
xm.append(4);
xm.append(5);
xm.append(6);
xm.append(7);
xm.append(8);
xm.append(9);
view = new QListView(this);
view->setModel(&xm);
xm.append(10); // should call beginInsertRows, append to valuelist, and call endInsertRows.
Q_ASSERT(valuelist.contains(10));
view->show();
}
Otherwise, you could perhaps create a mix of QObject and QList that can emit signals to notify XModel of changes, but I think the first approach is better.
Edit:
Here is a silly example. It will create a list-backed model that will append more elements to the list every second:
#include <QtGui/QApplication>
#include <QtGui/QListView>
#include <QtCore/QAbstractListModel>
#include <QtCore/QTimer>
class ListBackedModel : public QAbstractListModel
{
Q_OBJECT
QList<int>* m_list;
public:
ListBackedModel(QList<int>* list, QObject* parent = 0)
: QAbstractListModel(parent)
, m_list(list)
{}
~ListBackedModel()
{}
int rowCount(const QModelIndex &parent = QModelIndex()) const
{
Q_UNUSED(parent);
return m_list->size();
}
QVariant data(const QModelIndex &index, int role) const
{
if (index.row() >= rowCount()) { return QVariant(); }
if (index.row() < 0) { return QVariant(); }
int element = m_list->at(index.row());
if (Qt::DisplayRole == role) {
return QString::number(element);
}
if (Qt::ToolTipRole == role) {
return tr("%1 is element #%2").arg(element).arg(index.row() + 1);
}
return QVariant();
}
void append(int element)
{
/*
First is the new index of the first element that will be inserted.
Last is the new index of the last element that will be inserted.
Since we're appending only one element at the end of the list, the
index of the first and last elements is the same, and is equal to
the current size of the list.
*/
int first = m_list->size();
int last = first;
beginInsertRows(QModelIndex(), first, last);
m_list->append(element);
endInsertRows();
}
void startAddingMoreElements()
{
QTimer::singleShot(1000, this, SLOT(addMoreElements()));
}
private slots:
void addMoreElements()
{
append(qrand() % 100);
startAddingMoreElements();
}
};
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QList<int> list;
list << 1 << 10 << 34 << 111;
ListBackedModel model(&list);
QListView listView;
listView.setModel(&model);
listView.show();
model.startAddingMoreElements();
return a.exec();
}
#include "main.moc"

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