WidgetGrid: Proper animations when widgets are added or removed etc

To make that possible a major refactoring was needed. Had to ditch
Column{} and go for a full custom implementation. Tried to use ListView
but it didn't work well as widget additions and removals also affected
sizes and positions of other items in the list and ListView wasn't designed
for that. There's also the case that when there's a single item in the list
it should be centered and have a certain size, and I would have to torture
ListView quite a lot to get this implemented.

Now WidgetListModel is an integral part of WidgetGrid and thus was moved
inside it. The model and the qml code work hand in hand.

Removed all header dependencies from WidgetListModel and put it into a plugin
so that WidgetGrid could still be used in qml tests and be fed with a model
fully written in qml.

Also removed appman dependencies in ApplicationInfo.

5 files changed, 591 insertions, 0 deletions

diff --git a/plugins/widgetgrid/WidgetGridPlugin.cpp b/plugins/widgetgrid/WidgetGridPlugin.cpp
new file mode 100644
index 00000000..cbe1c19a
--- /dev/null
+++ b/plugins/widgetgrid/WidgetGridPlugin.cpp
@@ -0,0 +1,49 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 Pelagicore AG
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Triton IVI UI.
+**
+** $QT_BEGIN_LICENSE:GPL-QTAS$
+** Commercial License Usage
+** Licensees holding valid commercial Qt Automotive Suite licenses may use
+** this file in accordance with the commercial license agreement provided
+** with the Software or, alternatively, in accordance with the terms
+** contained in a written agreement between you and The Qt Company.  For
+** licensing terms and conditions see https://www.qt.io/terms-conditions.
+** For further information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 or (at your option) any later version
+** approved by the KDE Free Qt Foundation. The licenses are as published by
+** the Free Software Foundation and appearing in the file LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+** SPDX-License-Identifier: GPL-3.0
+**
+****************************************************************************/
+#include <QQmlExtensionPlugin>
+#include <QQmlEngine>
+
+#include "WidgetListModel.h"
+
+class WidgetGridPlugin : public QQmlExtensionPlugin
+{
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID QQmlExtensionInterface_iid)
+
+public:
+    void registerTypes(const char *uri)
+    {
+        Q_ASSERT(uri == QLatin1String("TritonWidgetGrid"));
+        qmlRegisterType<WidgetListModel>(uri, 1, 0, "WidgetListModel");
+    }
+};
+
+#include "WidgetGridPlugin.moc"
diff --git a/plugins/widgetgrid/WidgetListModel.cpp b/plugins/widgetgrid/WidgetListModel.cpp
new file mode 100644
index 00000000..26713102
--- /dev/null
+++ b/plugins/widgetgrid/WidgetListModel.cpp
@@ -0,0 +1,396 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 Pelagicore AG
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Triton IVI UI.
+**
+** $QT_BEGIN_LICENSE:GPL-QTAS$
+** Commercial License Usage
+** Licensees holding valid commercial Qt Automotive Suite licenses may use
+** this file in accordance with the commercial license agreement provided
+** with the Software or, alternatively, in accordance with the terms
+** contained in a written agreement between you and The Qt Company.  For
+** licensing terms and conditions see https://www.qt.io/terms-conditions.
+** For further information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 or (at your option) any later version
+** approved by the KDE Free Qt Foundation. The licenses are as published by
+** the Free Software Foundation and appearing in the file LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+** SPDX-License-Identifier: GPL-3.0
+**
+****************************************************************************/
+#include "WidgetListModel.h"
+
+#include <QDebug>
+
+int WidgetListModel::rowCount(const QModelIndex &/*parent*/) const
+{
+    return m_list.count();
+}
+
+QVariant WidgetListModel::data(const QModelIndex &index, int role) const
+{
+    if (index.row() >= 0 && index.row() < m_list.count()) {
+        const ListItem &listItem = m_list.at(index.row());
+        if (role == RoleAppInfo) {
+            return QVariant::fromValue(listItem.appInfo);
+        } else if (role == RoleRowIndex) {
+            return QVariant::fromValue(listItem.rowIndex);
+        }
+    }
+    return QVariant();
+}
+
+QAbstractItemModel *WidgetListModel::applicationModel() const
+{
+    return m_applicationModel;
+}
+
+void WidgetListModel::setApplicationModel(QAbstractItemModel *appModel)
+{
+    if (appModel == m_applicationModel) {
+        return;
+    }
+    setPopulating(true);
+
+    disconnect(appModel, 0, this, 0);
+    m_list.clear();
+
+    m_applicationModel = appModel;
+    emit applicationModelChanged();
+
+    if (!appModel) {
+        return;
+    }
+
+    fetchAppInfoRoleIndex();
+
+    if (appModel->rowCount() > 0) {
+        trackRowsFromApplicationModel(0, appModel->rowCount() - 1);
+    }
+    setPopulating(false);
+
+    connect(appModel, &QAbstractItemModel::rowsInserted, this,
+            [this](const QModelIndex & /*parent*/, int first, int last)
+            {
+                this->trackRowsFromApplicationModel(first, last);
+            });
+
+    connect(appModel, &QAbstractItemModel::rowsAboutToBeRemoved, this,
+            [this](const QModelIndex & /*parent*/, int first, int last)
+            {
+                for (int i = first; i <= last; ++i) {
+                    auto *appInfo = getApplicationInfoFromModelAt(i);
+                    detachApplicationInfo(appInfo);
+                    remove(indexFromAppInfo(appInfo));
+                    disconnect(appInfo, 0, this, 0);
+                }
+            });
+
+    connect(appModel, &QAbstractItemModel::modelAboutToBeReset, this,
+            [this]()
+            {
+                beginResetModel();
+                m_resetting = true;
+                m_list.clear();
+            });
+
+    connect(appModel, &QAbstractItemModel::modelReset, this,
+            [this]()
+            {
+                trackRowsFromApplicationModel(0, m_applicationModel->rowCount() - 1);
+                m_resetting = false;
+                endResetModel();
+            });
+
+    connect(appModel, &QObject::destroyed, this,
+            [this]()
+            {
+                this->setApplicationModel(nullptr);
+            });
+}
+
+void WidgetListModel::fetchAppInfoRoleIndex()
+{
+    QHash<int, QByteArray> hash = m_applicationModel->roleNames();
+
+    m_appInfoRoleIndex = -1;
+    for (auto i = hash.begin(); i != hash.end() && m_appInfoRoleIndex == -1; ++i) {
+        if (i.value() == QByteArray("appInfo"))
+            m_appInfoRoleIndex = i.key();
+    }
+
+    Q_ASSERT(m_appInfoRoleIndex != -1);
+}
+
+QObject *WidgetListModel::application(int rowIndex)
+{
+    if (rowIndex >= 0 && rowIndex < m_list.count()) {
+        return m_list[rowIndex].appInfo;
+    } else {
+        return nullptr;
+    }
+}
+
+void WidgetListModel::move(int from, int to)
+{
+    qDebug().nospace() << "WidgetListModel::move(from="<<from<<", to="<<to<<")";
+
+    if (from == to) return;
+
+    if (from >= 0 && from < m_list.size() && to >= 0 && to < m_list.size()) {
+        QModelIndex parent;
+        /* When moving an item down, the destination index needs to be incremented
+           by one, as explained in the documentation:
+           http://qt-project.org/doc/qt-5.0/qtcore/qabstractitemmodel.html#beginMoveRows */
+
+        beginMoveRows(parent, from, from, parent, to + (to > from ? 1 : 0));
+        m_list.move(from, to);
+        endMoveRows();
+
+        updateRowIndexes();
+    }
+}
+
+void WidgetListModel::onAppWidgetStateChanged()
+{
+    QObject *appInfo = sender();
+    if (asWidget(appInfo)) {
+        appendApplicationInfo(appInfo);
+    } else {
+        detachApplicationInfo(appInfo);
+    }
+}
+
+void WidgetListModel::trackRowsFromApplicationModel(int first, int last)
+{
+    QList<ListItem> newRows;
+
+    for (int i = first; i <= last; ++i) {
+        auto *appInfo = getApplicationInfoFromModelAt(i);
+        bool ok;
+
+        ok = connect(appInfo, SIGNAL(asWidgetChanged()), this, SLOT(onAppWidgetStateChanged()));
+        if (!ok) qFatal("WidgetListModel: Failed to connect to ApplicationInfo::asWidgetChanged");
+
+        ok = connect(appInfo, SIGNAL(heightRowsChanged()), this, SLOT(updateRowIndexes()));
+        if (!ok) qFatal("WidgetListModel: Failed to connect to ApplicationInfo::heightRowsChanged");
+
+        if (asWidget(appInfo)) {
+            newRows.append(ListItem(appInfo));
+        }
+    }
+
+    if (newRows.isEmpty()) {
+        return;
+    }
+
+    if (!m_resetting) {
+        beginInsertRows(QModelIndex(), rowCount()/*first*/, rowCount() + newRows.count() - 1/*last*/);
+    }
+
+    m_list.append(newRows);
+
+    if (!m_resetting) {
+        endInsertRows();
+    }
+    emit countChanged();
+
+    updateRowIndexes();
+}
+
+void WidgetListModel::appendApplicationInfo(QObject *appInfo)
+{
+    // TODO: consider minHeight
+
+    // Shrink existing widgets to make way for the new one
+    auto list = filterOutDetachedItems(m_list);
+    if (list.count() > 0) {
+        for (int i = list.count() - 1; i >= 0; --i) {
+            auto *appInfo = list[i]->appInfo;
+            if (heightRows(appInfo) > 1) {
+                setHeightRows(appInfo, heightRows(appInfo) - 1);
+                break;
+            }
+        }
+    }
+
+    if (list.count() == 1) {
+        setHeightRows(appInfo, m_totalNumRows - heightRows(list[0]->appInfo));
+    } else {
+        setHeightRows(appInfo, 1);
+    }
+
+    beginInsertRows(QModelIndex(), rowCount()/*first*/, rowCount()/*last*/);
+    m_list.append(ListItem(appInfo));
+    updateRowIndexes();
+    endInsertRows();
+
+}
+
+void WidgetListModel::detachApplicationInfo(QObject *appInfoToRemove)
+{
+    int index = indexFromAppInfo(appInfoToRemove);
+    Q_ASSERT(index != -1);
+    if (index == -1) {
+        return;
+    }
+
+    m_list[index].detached = true;
+
+    if (filterOutDetachedItems(m_list).count() == 1) {
+        // Special case when there's only one widget left
+        updateRowIndexes();
+    } else {
+        // Make a neighbouring widget occupy the space left by the one being detached
+        int i = index + 1;
+        bool neighborExpanded = false;
+        while (i < m_list.count() && !neighborExpanded) {
+            auto &listItem = m_list[i];
+            if (listItem.detached) {
+                ++i;
+            } else {
+                auto *nextAppInfo = listItem.appInfo;
+                setHeightRows(nextAppInfo, heightRows(nextAppInfo) + heightRows(appInfoToRemove));
+                neighborExpanded = true;
+            }
+        }
+        i = index - 1;
+        while (i >= 0 && !neighborExpanded) {
+            auto &listItem  = m_list[i];
+            if (listItem.detached) {
+                --i;
+            } else {
+                auto *previousAppInfo = listItem.appInfo;
+                setHeightRows(previousAppInfo, heightRows(previousAppInfo) + heightRows(appInfoToRemove));
+                neighborExpanded = true;
+            }
+        }
+    }
+}
+
+void WidgetListModel::remove(int index)
+{
+    if (index >= 0 && index < m_list.count()) {
+        beginRemoveRows(QModelIndex(), index, index);
+        m_list.removeAt(index);
+        endRemoveRows();
+    }
+}
+
+QObject *WidgetListModel::getApplicationInfoFromModelAt(int index)
+{
+    auto rowIndex = m_applicationModel->index(index, 0, QModelIndex());
+    QVariant variant = m_applicationModel->data(rowIndex, m_appInfoRoleIndex);
+    auto appInfo = variant.value<QObject*>();
+
+    if (!appInfo) {
+        qFatal("WidgetListModel: Invalid source model");
+    }
+
+    return appInfo;
+}
+
+void WidgetListModel::updateRowIndexes()
+{
+    if (m_updatingRowIndexes) {
+        // avoid recursion
+        return;
+    }
+
+    m_updatingRowIndexes = true;
+
+    QVector<int> roles;
+    roles.append(RoleRowIndex);
+
+    auto list = filterOutDetachedItems(m_list);
+
+    if (list.count() == 1) {
+        // special case
+        ListItem *listItem = list[0];
+
+        listItem->rowIndex = 1;
+
+        auto modelIndex = index(indexFromAppInfo(listItem->appInfo));
+        emit dataChanged(modelIndex, modelIndex, roles);
+
+        setHeightRows(listItem->appInfo, 3);
+    } else {
+        int accumulatedRows = 0;
+        for (int i = 0; i < m_list.count(); ++i) {
+            ListItem &listItem = m_list[i];
+
+            if (listItem.detached)
+                continue;
+
+            if (accumulatedRows != listItem.rowIndex) {
+                listItem.rowIndex = accumulatedRows;
+
+                auto modelIndex = index(i);
+                emit dataChanged(modelIndex, modelIndex, roles);
+            }
+
+            accumulatedRows += heightRows(listItem.appInfo);
+        }
+    }
+
+    m_updatingRowIndexes = false;
+}
+
+int WidgetListModel::indexFromAppInfo(QObject *appInfo)
+{
+    for (int i = 0; i < m_list.count(); ++i) {
+        if (m_list[i].appInfo == appInfo) {
+            return i;
+        }
+    }
+    return -1;
+}
+
+int WidgetListModel::heightRows(QObject* appInfo) const
+{
+    return appInfo->property("heightRows").toInt();
+}
+
+void WidgetListModel::setHeightRows(QObject* appInfo, int value) const
+{
+    appInfo->setProperty("heightRows", QVariant(value));
+}
+
+bool WidgetListModel::asWidget(QObject *appInfo) const
+{
+    return appInfo->property("asWidget").toBool();
+}
+
+QString WidgetListModel::id(QObject *appInfo) const
+{
+    return appInfo->property("id").toString();
+}
+
+QList<WidgetListModel::ListItem*> WidgetListModel::filterOutDetachedItems(QList<ListItem> &list) const
+{
+    QList<ListItem*> filteredList;
+    for (int i = 0; i < list.count(); ++i) {
+        if (!list[i].detached) {
+            filteredList.append(&list[i]);
+        }
+    }
+    return filteredList;
+}
+
+void WidgetListModel::setPopulating(bool value)
+{
+    if (m_populating != value) {
+        m_populating = value;
+        emit populatingChanged();
+    }
+}
diff --git a/plugins/widgetgrid/WidgetListModel.h b/plugins/widgetgrid/WidgetListModel.h
new file mode 100644
index 00000000..bfe21f0e
--- /dev/null
+++ b/plugins/widgetgrid/WidgetListModel.h
@@ -0,0 +1,133 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 Pelagicore AG
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Triton IVI UI.
+**
+** $QT_BEGIN_LICENSE:GPL-QTAS$
+** Commercial License Usage
+** Licensees holding valid commercial Qt Automotive Suite licenses may use
+** this file in accordance with the commercial license agreement provided
+** with the Software or, alternatively, in accordance with the terms
+** contained in a written agreement between you and The Qt Company.  For
+** licensing terms and conditions see https://www.qt.io/terms-conditions.
+** For further information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 or (at your option) any later version
+** approved by the KDE Free Qt Foundation. The licenses are as published by
+** the Free Software Foundation and appearing in the file LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+** SPDX-License-Identifier: GPL-3.0
+**
+****************************************************************************/
+#pragma once
+
+#include <QAbstractListModel>
+#include <QObject>
+
+/*
+    Filters ApplicationModel to only show the applications that have asWidget==true and also
+    keeps its own order of applications, independently of ApplicationModel
+
+    Also defines the position of widgets in the grid (rowIndex role) and ensures they correctly
+    fill the grid (manipulates ApplicationInfo::heightRows)
+ */
+class WidgetListModel : public QAbstractListModel
+{
+    Q_OBJECT
+    Q_PROPERTY(QAbstractItemModel* applicationModel READ applicationModel WRITE setApplicationModel NOTIFY applicationModelChanged)
+    Q_PROPERTY(int count READ count NOTIFY countChanged)
+    Q_PROPERTY(bool populating READ populating NOTIFY populatingChanged)
+    Q_PROPERTY(int numRows READ numRows CONSTANT)
+public:
+    enum Roles {
+        RoleAppInfo = Qt::UserRole,
+        RoleRowIndex = Qt::UserRole + 1,
+    };
+
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
+    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
+    QHash<int, QByteArray> roleNames() const override
+    {
+        QHash<int, QByteArray> roleNames;
+        roleNames.insert(RoleAppInfo, "appInfo");
+        roleNames.insert(RoleRowIndex, "rowIndex");
+        return roleNames;
+    }
+
+    QAbstractItemModel *applicationModel() const;
+    void setApplicationModel(QAbstractItemModel *);
+
+    Q_INVOKABLE QObject *application(int index);
+
+    Q_INVOKABLE void move(int fromIndex, int toIndex);
+    Q_INVOKABLE void remove(int index);
+
+    int count() const { return rowCount(); }
+
+    bool populating() const { return m_populating; }
+
+    int numRows() const { return m_totalNumRows; }
+
+signals:
+    void applicationModelChanged();
+    void countChanged();
+    void populatingChanged();
+
+private slots:
+    void onAppWidgetStateChanged();
+    void updateRowIndexes();
+
+private:
+    void fetchAppInfoRoleIndex();
+
+    void trackRowsFromApplicationModel(int first, int last);
+    void appendApplicationInfo(QObject *appInfo);
+
+    // Keep it in the model but don't consider it as occupying the grid (it won't affect position of
+    // other widgets). Useful for animating the widget removal, before it finally leaves the model
+    void detachApplicationInfo(QObject *appInfo);
+
+    int indexFromAppInfo(QObject *appInfo);
+
+    QObject *getApplicationInfoFromModelAt(int index);
+
+    // some helpers to make code more readable when dealing with QObject properties
+    int heightRows(QObject *appInfo) const;
+    void setHeightRows(QObject *appInfo, int value) const;
+    bool asWidget(QObject *appInfo) const;
+    QString id(QObject *appInfo) const;
+
+    void setPopulating(bool);
+
+    int m_appInfoRoleIndex{-1};
+    QAbstractItemModel *m_applicationModel{nullptr};
+
+    struct ListItem {
+        ListItem() : appInfo(nullptr), rowIndex(0) {}
+        ListItem(QObject *appInfo) : appInfo(appInfo),rowIndex(0) {}
+        bool operator==(const ListItem &other) const { return appInfo == other.appInfo && rowIndex == other.rowIndex && detached == other.detached; }
+
+        QObject *appInfo;
+        int rowIndex;
+        bool detached{false};
+    };
+    QList<ListItem*> filterOutDetachedItems(QList<ListItem> &list) const;
+
+    QList<ListItem> m_list;
+    bool m_resetting{false}; // whether the model is being reset
+
+    bool m_updatingRowIndexes{false};
+
+    int m_totalNumRows{5};
+
+    bool m_populating{true};
+};
diff --git a/plugins/widgetgrid/qmldir b/plugins/widgetgrid/qmldir
new file mode 100644
index 00000000..a4685acd
--- /dev/null
+++ b/plugins/widgetgrid/qmldir
@@ -0,0 +1,2 @@
+module TritonWidgetGrid
+plugin widgetgridplugin
diff --git a/plugins/widgetgrid/widgetgrid.pro b/plugins/widgetgrid/widgetgrid.pro
new file mode 100644
index 00000000..97e2b9fc
--- /dev/null
+++ b/plugins/widgetgrid/widgetgrid.pro
@@ -0,0 +1,11 @@
+TEMPLATE = lib
+CONFIG += plugin
+QT += qml
+
+SOURCES += WidgetGridPlugin.cpp WidgetListModel.cpp
+HEADERS += WidgetListModel.h
+
+TARGET = widgetgridplugin
+
+uri = TritonWidgetGrid
+load(qmlplugin)