ListView not displaying

BlobModel.cpp

#include "app/qobjs/BlobModel.h"

#include <QtGlobal>

BlobModel::BlobModel(QObject* parent)
    : QAbstractListModel(parent) { }

BlobModel::~BlobModel()
{
    removeRows(0, rowCount());
}

auto BlobModel::Contains(const QString& uuid) -> int
{
    // Using canonical for here in order to get the index of an element
    for (int i = 0; i<rowCount(); i++)
    {
        auto b = blobs_[i];
        if (b->uuid() == uuid)
            return i;
    }

    return -1;
}

auto BlobModel::addBlob(const BlobPointDataPtr& data) -> void
{
    // Read the ID
    stBlobPointInfo info;
    data->GetBlobPointInfo(info);
    auto uuid = QString::fromStdString(info.uuid);

    const auto idx = Contains(uuid);
    if (-1 != idx)
    {
        blobs_[idx]->Update(data);
        Q_EMIT dataChanged(createIndex(idx, 0), createIndex(idx, 0));
    }
    else
    {
        if (blobs_.size() < static_cast<int>(max_blobs_)) {

            beginInsertRows(QModelIndex(), rowCount(), rowCount());
            blobs_ << new Blob{data, id_count_}; id_count_++;
            endInsertRows(); // responsible for the QQmlChangeSet

            Q_EMIT dataChanged(createIndex(rowCount(), 0), createIndex(rowCount(), 0));
        }
    }
}

auto BlobModel::removeRows(int row, int count, const QModelIndex& parent) -> bool
{
    if (count < 0)
    {
        qFatal("Invalid count provided in BlobModel::removeRows");
        return false;
    }
    if (row + count > rowCount())
        return false;
    if (!count)
        return true;

    beginRemoveRows(parent, row, row+count - 1);
    while (count > 0)
    {
        auto b = blobs_.takeAt(row);
        delete b;
        count--;
    }
    endRemoveRows();

    Q_EMIT countChanged(rowCount());

    return true;
}


auto BlobModel::rowCount(const QModelIndex& parent) const -> int
{
    Q_UNUSED(parent);
    return blobs_.size();
}

auto BlobModel::data(const QModelIndex& index, int role) const -> QVariant
{
    if(!index.isValid())
    {
        qWarning("Invalid index used.");
        return QVariant();
    }

    if (index.row() < 0 || index.row() >= blobs_.count())
    {
        qWarning("Invalid row requested.");
        return QVariant();
    }

    auto blob = blobs_[index.row()];

    if (role == CentroidRole)
        return blob->centroid();
    else if (role == IdRole)
        return blob->id();
    else if (role == ExtentsRole)
        return blob->extents();
    return QVariant();
}

auto BlobModel::roleNames() const -> QHash<int, QByteArray>
{
    QHash<int, QByteArray> roles;
    roles[CentroidRole] = "centroid";
    roles[ExtentsRole]  = "extents";
    roles[IdRole]  = "id";
    return roles;
}

/* vim: set ts=4 sw=4 sts=4 expandtab ffs=unix,dos : */

BlobModel.h

#ifndef BLOBSMODEL_H_VDJELPI1
#define BLOBSMODEL_H_VDJELPI1

#include <QAbstractListModel>
#include <QList>

#include "app/qobjs/Blob.h"

class BlobModel : public QAbstractListModel
{
    Q_OBJECT

    Q_PROPERTY(unsigned int count READ rowCount NOTIFY countChanged)

public:
    enum BlobRoles {
        CentroidRole = Qt::UserRole + 1,
        ExtentsRole,
        IdRole
    };

    BlobModel(QObject* parent = nullptr);

    /** Deletes all the blobs in the container */
    virtual ~BlobModel();

    /** Adds or updates a blob in the list */
    auto addBlob(const BlobPointDataPtr& data) -> void;

    /** Returns number of blobs in the list */
    auto rowCount(const QModelIndex& parent = QModelIndex()) const -> int;

    /** Fetch blob from the list */
    auto data(const QModelIndex& index, int role = Qt::DisplayRole) const -> QVariant;

    /** Set max number of blobs */
    auto setMaxBlobs(const unsigned int n) -> void { max_blobs_ = n; };

    /** Set max number of blobs */
    auto setMaxBufferPointCapacity(const unsigned int n) -> void { max_buffer_point_capacity_ = n; };

    /** Remove rows (blobs) from the model */
    auto removeRows(int row, int count, const QModelIndex& parent = QModelIndex()) -> bool;

    /**
     * Check whether the UUID exists in the list.  Returns the index if the
     * collection contains the blob, otherwise returns -1 for now found.
     */
    auto Contains(const QString& uuid) -> int;

signals:

    void countChanged(unsigned int count);

protected:
    QHash<int, QByteArray> roleNames() const;

private:
    Q_DISABLE_COPY(BlobModel);

    /**
     * List of blobs.
     */
    QList<Blob*> blobs_;

    /**
     * Maximum allowed number of blob objects at a time.
     **/
    unsigned int max_blobs_ = 100;

    /**
     * Max buffer point capacity.
    **/
    unsigned int max_buffer_point_capacity_ = 1024 * 100;

    unsigned int id_count_ = 0;
};

#endif /* end of include guard: BLOBSMODEL_H_VDJELPI1 */

/* vim: set ts=4 sw=4 sts=4 expandtab ffs=unix,dos : */

InfoPane.qml

import QtQuick 2.8
import QtQuick.Layouts 1.3
import QtQuick.Controls 1.4 as Qtc1
import QtQuick.Controls 2.1 as Qtc2

/**
 * Info window to display debug data to the user.
**/
Rectangle {
	Component {
		id: delegate
		Row {
			spacing: 10
			Text { text: "id: " + id + ", loc = " + centroid.x.toFixed(2); color: "white" }
		}
	}

	RowLayout {
		anchors.fill: parent

		Rectangle {
			Layout.fillHeight: true
			Layout.preferredWidth: 200
			Layout.maximumWidth: 200
			color: "transparent"

			ColumnLayout {
				anchors.fill: parent

				Text {
					text: "nBlobs = " + sceneGraph.blobs.count
					color: 'white';
				}

				Rectangle {

					Layout.fillWidth: true
					Layout.minimumWidth: 150
					Layout.preferredWidth: 180
					Layout.maximumWidth: 200

					Layout.minimumHeight: 200
					Layout.fillHeight: true

					color: Qt.rgba(0.1, 0.1, 0.3, 0.4)
					ListView {
						id: blobsView

						Layout.fillWidth: true
						Layout.minimumWidth: 150
						Layout.preferredWidth: 180
						Layout.maximumWidth: 200

						Layout.minimumHeight: 200
						Layout.fillHeight: true

						anchors.fill: parent

						model: sceneGraph.blobs
						delegate: delegate
					}
				}
			}
		}
	}
}

// vim: ts=3 sw=3 sts=0 noet ffs=unix ft=qml :