What would be the best way of selecting an item in a QT combo box out of a predefined list of enum based unique values.
In the past I have become accustomed to .NET's style of selection where the item can be selected by setting the selected property to the item's value you wish to select:
cboExample.SelectedValue = 2;
Is there anyway to do this with QT based on the item's data, if the data is a C++ enumeration?
You lookup the value of the data with findData() and then use setCurrentIndex()
QComboBox* combo = new QComboBox;
combo->addItem("100",100.0); // 2nd parameter can be any Qt type
combo->addItem .....
float value=100.0;
int index = combo->findData(value);
if ( index != -1 ) { // -1 for not found
combo->setCurrentIndex(index);
}
You can also have a look at the method findText(const QString & text) from QComboBox; it returns the index of the element which contains the given text, (-1 if not found).
The advantage of using this method is that you don't need to set the second parameter when you add an item.
Here is a little example :
/* Create the comboBox */
QComboBox *_comboBox = new QComboBox;
/* Create the ComboBox elements list (here we use QString) */
QList<QString> stringsList;
stringsList.append("Text1");
stringsList.append("Text3");
stringsList.append("Text4");
stringsList.append("Text2");
stringsList.append("Text5");
/* Populate the comboBox */
_comboBox->addItems(stringsList);
/* Create the label */
QLabel *label = new QLabel;
/* Search for "Text2" text */
int index = _comboBox->findText("Text2");
if( index == -1 )
label->setText("Text2 not found !");
else
label->setText(QString("Text2's index is ")
.append(QString::number(_comboBox->findText("Text2"))));
/* setup layout */
QVBoxLayout *layout = new QVBoxLayout(this);
layout->addWidget(_comboBox);
layout->addWidget(label);
If you know the text in the combo box that you want to select, just use the setCurrentText() method to select that item.
ui->comboBox->setCurrentText("choice 2");
From the Qt 5.7 documentation
The setter setCurrentText() simply calls setEditText() if the combo
box is editable. Otherwise, if there is a matching text in the list,
currentIndex is set to the corresponding index.
So as long as the combo box is not editable, the text specified in the function call will be selected in the combo box.
Reference: http://doc.qt.io/qt-5/qcombobox.html#currentText-prop
Related
I'm not sure if the title is correct but this is the situation:
When a row is selected and contains Application Status of FULL_MEMBER,
A pushButton is enabled else it is disabled.
You have to get the text of the item (cell) in the fifth column of the selected row, each time the selection changes.
Have a slot like this in your widget:
private slots:
void tableSelectionChanged();
In the widget constructor, connect it to the table widget signal itemSelectionChanged:
connect(ui->tableWidget, SIGNAL(itemSelectionChanged()), this, SLOT(tableSelectionChanged()));
The slot definition is like this:
//retrieve a list of all selected rows
QModelIndexList list = ui->tableWidget->selectionModel()->selectedRows();
if(list.size() > 0)
{
//retrieve the index of the first (and only, maybe?) selected row
int row = list[0].row();
const int col = 4; //Application Status column id
QTableWidgetItem * item = ui->tableWidget->item(row, col); //the item we want to inspect
ui->pushButton->setEnabled( item->text() == "FULL_MEMBER" );
}
I have a QTableWidget and for all rows I set a setCellWidget at one column to a button.
I would like to connect this button to a function that delets this row.
I tried this code, which does not work, because if I simply click my button I do not set the current row to the row of the button.
ui->tableWidget->insertRow(ui->tableWidget->rowCount());
QPushButton *b = new QPushButton("delete",this);
ui->tableWidget->setCellWidget(ui->tableWidget->rowCount()-1,0,b);
connect(d,SIGNAL(clicked(bool)),this,SLOT(deleteThisLine()));
...
void MainWindow::deleteThisLine()
{
int row = ui->tableWidget->currentRow();
ui->tableWidget->removeRow(row);
}
How can I connect my button to a function in a way that the function knows which button (at which row) was pressed?
To remove the row we must first get the row, if we are inserting widgets inside the cells the currentRow() method will not return the appropriate row, in many cases it will return the row of the last cell without widget that has been selected.
For that reason you must opt for another solution, for this case we will use the indexAt() method of QTableWidget, but for this we need to know the position in pixels of the cell. when one adds a widget to a cell, this cell will be the parent of the widget, so we can access from the button to the cell using the parent() method, and then get the position of the cell with respect to the QTableWidget and use it in indexAt(). To access the button we will use the sender().
When the current cell is removed the focus is lost, a possible solution is to place the focus again in another cell.
void MainWindow::deleteThisLine()
{
//sender(): QPushButton
QWidget *w = qobject_cast<QWidget *>(sender()->parent());
if(w){
int row = ui->tableWidget->indexAt(w->pos()).row();
ui->tableWidget->removeRow(row);
ui->tableWidget->setCurrentCell(0, 0);
}
}
Use this connection way to connect signal to a slot:
connect(ui->btnDelete, &QPushButton::clicked, this,&MainWindow::deleteRow);
And delete for example a row on call function:
void MainWindow::deleteRow()
{
int row = ui->tableWidget->currentRow();
ui->tableWidget->removeRow(row);
}
Create a custom class, where you pass the created push button object and the row index. From your custom push button class, handle the push button press event and emit a custom signal (it will carry the index number) handled from the object where your custom pushbutton is created. Some related code are below, to give you a hint:
.h
class mypushbutton {
explicit mypushbutton(QObject *parent = 0, QPushButton *pushbutton = 0, int index = 0);
signal:
void deleteRow(int index);
}
.cpp
mypushbutton() {
connect(pushbutton, SIGNAL(clicked(bool)), this, SLOT(actionButtonClick(bool)));
}
actionbuttonclicked() { emit deleteRow(index);}
What i'm trying is to get the row number of QcomboBox when user selects items. Although its easy to to get the cell column and row using
cellClicked(int,int)
signal, but it only works when there is no widget on the cell.
so how to get the row number in case if there is a widget placed in a cell.
Note: All the combobox are added dynamically
At-last i found 2 ways of doing it.
By setting the property of QComboBox
Using the QSignalMapper
First Method
QComboBox* mCombo = new QCombobox();
mComboBox->setProperty("row",(int) i); // i represents the row number in qtablewidget
In handler function where you are handling the clicked QComboBox
int row = sender()->property("row").toInt();
Second Method
QSignalMapper *signalMapper= new QSignalMapper(this); //Create a signal mapper instance
for (each row in table) {
QComboBox* mCombo = new QComboBox();
table->setCellWidget(row,col,combo);
connect(mCombo, SIGNAL(currentIndexChanged(int)), signalMapper, SLOT(map()));
/*connect each signal of QComboBox to signal Mapper slot (i.e map()) which in turns connected to the signal of signalMapper calling the SLOT associated with it (i.e rowFinder) */
signalMapper->setMapping(combo, (int)row); //assign mapping to each widgetusing set mapping
}
connect(signalMapper, SIGNAL(mapped(int)),
this, SLOT(rowFinder(int)));
function : rowFinder(int rowIndex)
int row = rowIndex; //here is the row indexof selected QComboBox
I'm making a Qt5.7 application where I am populating a QListView after reading stuff from a file. Here's the exact code of it.
QStringListModel *model;
model = new QStringListModel(this);
model->setStringList(stringList); //stringList has a list of strings
ui->listView->setModel(model);
ui->listView->setEditTriggers(QAbstractItemView::NoEditTriggers); //To disable editing
Now this displays the list just fine in a QListView that I have set up. What I need to do now is to get the string that has been double clicked and use that value elsewhere. How do I achieve that?
What I tried doing was to attach a listener to the QListView this way
... // the rest of the code
connect(ui->listView, SIGNAL(doubleClicked(QModelIndex)), this, SLOT(fetch()));
...
And then I have the function fetch
void Window::fetch () {
qDebug() << "Something was clicked!";
QObject *s = sender();
qDebug() << s->objectName();
}
However the objectName() function returns "listView" and not the listView item or the index.
The signal already provides you with a QModelIndex which was clicked.
So you should change your slot to this:
void Window::fetch (QModelIndex index)
{
....
QModelIndex has now a column and a row property. Because a list has no columns you are interessted in the row. This is the index of the item clicked.
//get model and cast to QStringListModel
QStringListModel* listModel= qobject_cast<QStringListModel*>(ui->listView->model());
//get value at row()
QString value = listModel->stringList().at(index.row());
You should add the index as parameter of your slot. You can use that index to access the list
Your code should be some thing like this.
void Window::fetch (QModelIndex index) {
/* Do some thing you want to do*/
}
In Gtkmm, I want to have a Gtk TreeView with a ListStore, and have one of the columns in the list be a ComboBoxText. But I can't seem to figure out how to do it.
What I currently have looks like:
class PlayerListColumns : public Gtk::TreeModelColumnRecord
{
public:
PlayerListColumns()
{ add(name); add(team);}
TreeModelColumn<string> name;
TreeModelColumn<ComboBoxText*> team;
}
Then when setting the TreeView (the player_list_view object)
PlayerListColumns *columns = new PlayerListColumns();
Glib::RefPtr<ListStore> refListStore = ListStore::create(*columns);
player_list_view->set_model(refListStore);
ComboBoxText *box = manage(new ComboBoxText());
box->append("Blah");
box->append("Blah");
box->append("Blah");
TreeModel::Row row = *(refListStore->append());
row[columns->name] = "My Name";
row[columns->team] = box;
The column "name" shows up just fine, but no ComboBox. I'm almost positive that simply having a pointer to a combo box as the column type is wrong, but i don't know how it's supposed to go. I do get GTK warning:
GLib-GObject-WARNING **: unable to set property text' of typegchararray' from value of type `GtkComboBoxText'
Which seems to indicate (from a small bit of Googling) that there isn't a default renderer for non-basic types. But I haven't been able to find any examples of how to set one up, if that were the problem. All the tutorials only show TreeViews with primitive data types.
Anyone know how to put a ComboBox into a TreeView?
Okay, I haven't gotten it working 100%, but this example class should get you on the right track:
http://svn.gnome.org/svn/gtkmm-documentation/trunk/examples/book/treeview/combo_renderer/
Basically you need to add a Gtk::TreeModelColumn<Glib::RefPtr<Gtk::ListStore> > to your columns class and a Gtk::TreeModelColumn<string> to hold the selected data.
Then, to make a column a combobox, you have to add:
//manually created column for the tree view
Gtk::TreeViewColumn* pCol = Gtk::manage(new Gtk::TreeViewColumn("Choose"));
//the combobox cell renderer
Gtk::CellRendererCombo* comboCell = Gtk::manage(new Gtk::CellRendererCombo);
//pack the cell renderer into the column
pCol->pack_start(*comboCell);
//append the column to the tree view
treeView->append_column(*pCol);
//this sets the properties of the combobox and cell
//my gtkmm seems to be set for Glibmm properties
#ifdef GLIBMM_PROPERTIES_ENABLED
pCol->add_attribute(comboCell->property_text(), columns->team);
//this is needed because you can't use the ComboBoxText shortcut
// you have to create a liststore and fill it with your strings separately
// from your main model
pCol->add_attribute(comboCell->property_model(), columns->teams);
comboCell->property_text_column() = 0;
comboCell->property_editable() = true;
#else
pCol->add_attribute(*comboCell, "text", columns->team);
pCol->add_attribute(*comboCell, "model", columns->teams);
comboCell->set_property(text_column:, 0);
comboCell->set_property("editable", true);
#endif
//connect a signal so you can set the selected option back into the model
//you can just have a column that is not added to the view if you want
comboCell->signal_edited()
.connect(sigc::mem_fun(*this,&ComboWindow::on_combo_choice_changed));
EDIT ABOVE
I think something along the lines of using a Gtk::CellRendererCombo* is the way to go in your PlayerListColumns
http://developer.gnome.org/gtkmm/stable/classGtk_1_1CellRendererCombo.html
(I haven't made a working test yet, but I got the idea from:
http://developer.gnome.org/gtkmm-tutorial/unstable/sec-treeview.html.en#treeview-cellrenderer-details)