Making only one column of a QTreeWidgetItem editable

Question

I have a QTreeWidgetItem with two columns of data, is there any way to make only the second column editable? When I do the following:

QTreeWidgetItem* item = new QTreeWidgetItem();
item->setFlags(item->flags() | Qt::ItemIsEditable);

all columns become editable.

Answer 1

You can make only certain columns in a QTreeWidget editable using a workaround:

1) Set the editTriggers property of the QTreeWidget to NoEditTriggers

2) On inserting items, set the Qt:ItemIsEditable flag of the QTreeWidgetItem object

3) Connect the following slot to the "itemDoubleClicked" signal of the QTreeWidget object:

void MainWindow::onTreeWidgetItemDoubleClicked(QTreeWidgetItem * item, int column)
{
    if (isEditable(column)) {
        ui.treeWidget->editItem(item, column);
    }
}

where "isEditable" is a function you wrote that returns true for editable columns and false for non-editable columns.

Answer 2

I had the same problem recently and discovered a solution which works with all EditTriggers, not only the DoubleClicked one (and the connection to the double clicked signal)

Create a Delegate, that returns a NULL Pointer for the editor:

class NoEditDelegate: public QStyledItemDelegate {
    public:
      NoEditDelegate(QObject* parent=0): QStyledItemDelegate(parent) {}
      virtual QWidget* createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const {
        return 0;
      }
    };

And later use it as a custom delegate for your column

ui->parameterView->setItemDelegateForColumn(0, new NoEditDelegate(this));

Answer 3

Looks like you will have to forgo using QTreeWidget and QTreeWidgetItem and go with QTreeView and QAbstractItemModel. The "Widget" classes are convenience classes that are concrete implementations of the more abstract but more flexible versions. QAbstractItemModel has a call flags(QModelIndex index) where you would return the appropriate value for your column.