How to add progress bar to specific treeview row,column?

SRaD

Using Qt5. I'm trying to add a progress bar to the second column of a QTreeView, but only to a specific row, not the entire second column. Below is what I have, but nothing shows other than what I put in the first columns.

//progress.h
class ProgressDelegate : public QStyledItemDelegate
{           
    Q_OBJECT

    public: 
        ProgressDelegate(QObject *parent = 0); 
        
        void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index ) const override;
};           

//progress.cpp
ProgressDelegate::ProgressDelegate(QObject *parent) :
QStyledItemDelegate(parent) { }

void ProgressDelegate::paint(QPainter *painter,
const QStyleOptionViewItem &option,
const QModelIndex &index ) const // override
{
    if (index.column() == 2)
    {
        QStyleOptionProgressBar progressBarOption;
        progressBarOption.state = QStyle::State_Enabled;
        progressBarOption.direction = QApplication::layoutDirection();
        progressBarOption.rect = option.rect;
        progressBarOption.fontMetrics = QApplication::fontMetrics();
        progressBarOption.minimum = 0;
        progressBarOption.maximum = 100;
        progressBarOption.textAlignment = Qt::AlignCenter;
        progressBarOption.textVisible = true;

        QApplication::style()->drawControl(QStyle::CE_ProgressBar,
        &progressBarOption, painter);
    }
    else
        QStyledItemDelegate::paint(painter, option, index);

    return;
}         

// main-window.cpp

testModel = new QStandardItemModel(2, 2);
testModel->setHorizontalHeaderLabels(headers);
    
treeView = new QTreeView;
delegate = new ProgressDelegate(this);
treeView->setModel(testModel);

QString a = QString::fromStdString("stringA");
QStandardItem *ai = new QStandardItem(a);

QString b = QString::fromStdString("stringB");
QStandardItem *bi = new QStandardItem(b);

ai->appendRow(bi);

testModel.setItem(1, 0, ai);

I can see that I don't have a call to somehow put the progress bar in the column, but I'm not sure how that works.

KillerSmath

@SRaD Hi there.
Firstly, the counter of rows and columns begins in 0, so if you are trying to set a personal paint in the Second Column, you should to use index.column() == 1

Don't forget that in Father and Children model, the count of row and column is reseted when you set an item as the child of another item.

Image from QT - Model/View Tutorial

Row and column system

QModexIndex has 3 important Attributes:

row
column
parent

For default, if you call parent() function of an item that haven't father, it will return a standard QModexIndex

Below is an example of how you can set a progress bar in the item of first row, second column and in top father level.

void ProgressDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index ) const // override
{
    if (index.row() == 0 && index.column() == 1 && index.parent() == QModelIndex()) // first row, second column, at top father level
    {
        QStyleOptionProgressBar progressBarOption;
        progressBarOption.state = QStyle::State_Enabled;
        progressBarOption.direction = QApplication::layoutDirection();
        progressBarOption.rect = option.rect;
        progressBarOption.fontMetrics = QApplication::fontMetrics();
        progressBarOption.minimum = 0;
        progressBarOption.maximum = 100;
        progressBarOption.textAlignment = Qt::AlignCenter;
        progressBarOption.textVisible = true;

        QApplication::style()->drawControl(QStyle::CE_ProgressBar,
        &progressBarOption, painter);
    }
    else
        QStyledItemDelegate::paint(painter, option, index);
}

Read More:
http://doc.qt.io/qt-5/qmodelindex.html
http://doc.qt.io/qt-5/model-view-programming.html

SRaD

Still not seeing progress bars. Here is my tree, and my understanding of row/col id's.

Root Item (this is column 0)
    +- row = 0 (this is column 1)
	+ row = 0 (column 2, progress bar here)
	+ row = 1 (column 2, progress bar here)
	+ row = 2 (column 2, progress bar here)
+- row = 1 (this is column 1)
	+ row = 0 (column 2, progress bar here)
	+ row = 1 (column 2, progress bar here)
	+ row = 2 (column 2, progress bar here)

Since I only want to have progress bars to the 3 items in the second column, here is how I set my paint method ...

void ProgressDelegate::paint(QPainter *painter, 
const QStyleOptionViewItem &option,
const QModelIndex &index ) const // override
{
    if (index.column() == 2 && index.parent() != QModelIndex())
    {
    // ...

However, I still see nothing showing up in the second column of my treeview.

KillerSmath

@SRaD

Is the element (row 0, column 2) a child of element ( row 0, column 1) ?
I am not understanding why your column index is incrementing...

When an element is appended as child of another, their counters starts in (0,0) again.

SRaD

"Is the element (row 0, column 2) a child of element ( row 0, column 1) ?"
Yes, row 0, column 2 is a child of row 0, column 1.

"I am not understanding why your column index is incrementing..."
Doesn't each new column to the right increment? I have 3 columns.

"When an element is appended as child of another, their counters starts in (0,0) again."
And I think I have that. I don't see where I'm going wrong.

Edit:
I think I see where I might be going wrong. I thought each new append is a new column, but I see in my treevew, this hierarchy shows up in column 1 (or 0) of the treeview and I'm trying to put a progress bar in column 2 (or 1) of the treeview. I think I'm thinking each new child is a column.

So therefore, I've changed index.column() == 1 thinking this is the 2nd column of my treeview, not the hierarchy above. But still not seeing a progress bar.

void ProgressDelegate::paint(QPainter *painter, 
    const QStyleOptionViewItem &option,
    const QModelIndex &index ) const // override
{
    if (index.column() == 1 && index.parent() != QModelIndex())
    {
    // ...

KillerSmath

@SRaD

Look, think in a tree model setted up as below example:

Item A (0,0,0)
- Item 1 (0,0,1)
  - Item P1 (0,0,2)
  - Item P2 (1,0,2)
  - Item P3 (2,0,2)
- Item 2 (1,0,1)
  - Item P1 (0,0,2)
  - Item P2 (1,0,2)
  - Item P3 (2,0,2)
- Item 3 (2,0,1)
  - Item P1 (0,0,2)
  - Item P2 (1,0,2)
  - Item P3 (2,0,2)

Note: Each child has a Z Level depending of their parent but the value of (X,Y) is reseted for each append.

To set the Progressbar if the element is grandchild, you could to calculate the Z Level using the Parent of this element.

Example:

void ProgressDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, 
                             const QModelIndex &index ) const // override
{
    int z = 0;

    for(QModelIndex parentIndex = index.parent(); parentIndex.isValid(); z++){
        parentIndex = parentIndex.parent();
    }

    if (index.column() == 0 && z==2)
    {
        QStyleOptionProgressBar progressBarOption;
        progressBarOption.state = QStyle::State_Enabled;
        progressBarOption.direction = QApplication::layoutDirection();
        progressBarOption.rect = option.rect;
        progressBarOption.fontMetrics = QApplication::fontMetrics();
        progressBarOption.minimum = 0;
        progressBarOption.maximum = 100;
        bool isNumber;
        int number = index.data(Qt::DisplayRole).toInt(&isNumber);
        if(isNumber){
            progressBarOption.progress = number;
        }
        progressBarOption.textAlignment = Qt::AlignCenter;
        progressBarOption.textVisible = true;

        QApplication::style()->drawControl(QStyle::CE_ProgressBar,
                                           &progressBarOption, painter);
    }
    else
        QStyledItemDelegate::paint(painter, option, index);
}

    QStandardItemModel *model = new QStandardItemModel(0,1,this);
    model->setHorizontalHeaderItem(0, new QStandardItem("Main Column"));

    ProgressDelegate *delegate = new ProgressDelegate(this);
    ui->treeView->setItemDelegate(delegate);
    ui->treeView->setModel(model);

    QStandardItem *ia;
    QStandardItem *i1,*i2,*i3;
    QStandardItem *p1,*p2,*p3;

    // (Row , Column , Z Level)

    ia = new QStandardItem("Item A"); // (0,0,0)

        i1 = new QStandardItem("Item 1"); // (0,0,1)

            p1 = new QStandardItem("15"); // (0,0,2)
            p2 = new QStandardItem("30"); // (1,0,2)
            p3 = new QStandardItem("12"); // (2,0,2)

            i1->appendRow(p1);
            i1->appendRow(p2);
            i1->appendRow(p3);

        ia->appendRow(i1);

        i2 = new QStandardItem("Item 2"); // (1,0,1)

            p1 = new QStandardItem("35"); // (0,0,2)
            p2 = new QStandardItem("77"); // (1,0,2)
            p3 = new QStandardItem("12"); // (2,0,2)

            i2->appendRow(p1);
            i2->appendRow(p2);
            i2->appendRow(p3);

        ia->appendRow(i2);

        i3 = new QStandardItem("Item 3"); // (2,0,1)

            p1 = new QStandardItem("7"); // (0,0,2)
            p2 = new QStandardItem("22"); // (1,0,2)
            p3 = new QStandardItem("85");// (2,0,2)

            i3->appendRow(p1);
            i3->appendRow(p2);
            i3->appendRow(p3);

        ia->appendRow(i3);

    model->appendRow(ia); // (0,0,0)

Result

result_image

But this solution has a processing overhead to calculate the Z Level using the For Loop each time that paint event is called, so, seriously, the best solution is calculate the Z Level when the Data is appended on Model.

Pseudo-code - when insert the data or changing the root:

if has parent then
  Data[Z_Role] := parent_z_level + 1
else
  Data[Z_Role] := 0

You could easily get the Z Level on Delegate with this functionality

// Z_Role = Qt::UserRole+1
int zLevel = index.data(Qt::UserRole+1).toInt()