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unity8/plugins/ListViewWithPageHeader/listviewwithpageheader.h
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1/*
2 * Copyright (C) 2013 Canonical, Ltd.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; version 3.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program. If not, see <http://www.gnu.org/licenses/>.
15 */
17#ifndef LISTVIEWWITHPAGEHEADER_H
18#define LISTVIEWWITHPAGEHEADER_H
20#pragma GCC diagnostic push
21#pragma GCC diagnostic ignored "-pedantic"
22#include <private/qquickitemchangelistener_p.h>
23#include <private/qquickflickable_p.h>
24#pragma GCC diagnostic pop
26class QAbstractItemModel;
27class QQuickNumberAnimation;
28#if (QT_VERSION < QT_VERSION_CHECK(5, 1, 0))
29class QQuickChangeSet;
30class QQuickVisualDataModel;
31#else
32class QQmlChangeSet;
33class QQmlDelegateModel;
34#endif
37/**
38 Note for users of this class
40 ListViewWithPageHeader already loads delegates async when appropiate so if
41 your delegate uses a Loader you should not enable the asynchronous feature since
42 that will need to introduce sizing problems
44 With the double async it may happen what while we are scrolling down
45 we reach to a point where given the size of the just created delegate with loader not yet loaded (which will be very close to 0)
46 we are already "at the end" of the list, but then a few milliseconds later the loader finishes loading and we could
47 have kept scrolling. This is specially visible at the end of the list where you realize
48 that scrolling ended a bit before the end of the list but the speed of the flicking was good
49 to reach the end
51 By not having the second async we get a better sizing when the delegate is created and things work better
52*/
54class ListViewWithPageHeader : public QQuickFlickable, public QQuickItemChangeListener
56 Q_OBJECT
57 Q_PROPERTY(QAbstractItemModel *model READ model WRITE setModel NOTIFY modelChanged)
58 Q_PROPERTY(QQmlComponent *delegate READ delegate WRITE setDelegate NOTIFY delegateChanged)
59 Q_PROPERTY(QQuickItem *pageHeader READ header WRITE setHeader NOTIFY headerChanged)
60 Q_PROPERTY(QQmlComponent *sectionDelegate READ sectionDelegate WRITE setSectionDelegate NOTIFY sectionDelegateChanged)
61 Q_PROPERTY(QString sectionProperty READ sectionProperty WRITE setSectionProperty NOTIFY sectionPropertyChanged)
62 Q_PROPERTY(bool forceNoClip READ forceNoClip WRITE setForceNoClip NOTIFY forceNoClipChanged)
63 Q_PROPERTY(int stickyHeaderHeight READ stickyHeaderHeight NOTIFY stickyHeaderHeightChanged)
65 friend class ListViewWithPageHeaderTest;
66 friend class ListViewWithPageHeaderTestSection;
67 friend class ListViewWithPageHeaderTestExternalModel;
69public:
70 ListViewWithPageHeader();
71 ~ListViewWithPageHeader();
73 QAbstractItemModel *model() const;
74 void setModel(QAbstractItemModel *model);
76 QQmlComponent *delegate() const;
77 void setDelegate(QQmlComponent *delegate);
79 QQuickItem *header() const;
80 void setHeader(QQuickItem *header);
82 QQmlComponent *sectionDelegate() const;
83 void setSectionDelegate(QQmlComponent *delegate);
85 QString sectionProperty() const;
86 void setSectionProperty(const QString &property);
88 bool forceNoClip() const;
89 void setForceNoClip(bool noClip);
91 int stickyHeaderHeight() const;
93 Q_INVOKABLE void positionAtBeginning();
94 Q_INVOKABLE void showHeader();
95 Q_INVOKABLE QQuickItem *item(int modelIndex) const;
97 // The index has to be created for this to try to do something
98 // Created items are those visible and the precached ones
99 // Returns if the item existed or not
100 Q_INVOKABLE bool maximizeVisibleArea(int modelIndex);
101 Q_INVOKABLE bool maximizeVisibleArea(int modelIndex, int itemHeight);
103Q_SIGNALS:
104 void modelChanged();
105 void delegateChanged();
106 void headerChanged();
107 void sectionDelegateChanged();
108 void sectionPropertyChanged();
109 void forceNoClipChanged();
110 void stickyHeaderHeightChanged();
112protected:
113 void componentComplete();
114 void viewportMoved(Qt::Orientations orient);
115 qreal minYExtent() const;
116 void itemGeometryChanged(QQuickItem *item, const QRectF &newGeometry, const QRectF &oldGeometry);
117 void updatePolish();
119private Q_SLOTS:
120#if (QT_VERSION < QT_VERSION_CHECK(5, 1, 0))
121 void itemCreated(int modelIndex, QQuickItem *item);
122#else
123 void itemCreated(int modelIndex, QObject *object);
124#endif
125 void onContentHeightChanged();
126 void onContentWidthChanged();
127 void onHeightChanged();
128#if (QT_VERSION < QT_VERSION_CHECK(5, 1, 0))
129 void onModelUpdated(const QQuickChangeSet &changeSet, bool reset);
130#else
131 void onModelUpdated(const QQmlChangeSet &changeSet, bool reset);
132#endif
133 void onShowHeaderAnimationFinished();
135private:
136 class ListItem
137 {
138 public:
139 qreal height() const;
141 qreal y() const;
142 void setY(qreal newY);
144 bool culled() const;
145 void setCulled(bool culled);
147 QQuickItem *m_item;
148 QQuickItem *m_sectionItem;
149 };
151 bool maximizeVisibleArea(ListItem *listItem, int listItemHeight);
153 void createDelegateModel();
155 void layout();
156 void refill();
157 bool addVisibleItems(qreal fillFrom, qreal fillTo, bool asynchronous);
158 bool removeNonVisibleItems(qreal bufferFrom, qreal bufferTo);
159 ListItem *createItem(int modelIndex, bool asynchronous);
161 void adjustMinYExtent();
162 void updateClipItem();
163 void headerHeightChanged(qreal newHeaderHeight, qreal oldHeaderHeight, qreal oldHeaderY);
164 ListItem *itemAtIndex(int modelIndex) const; // Returns the item at modelIndex if has been created
165 void releaseItem(ListItem *item);
166 void reallyReleaseItem(ListItem *item);
167 void updateWatchedRoles();
168 QQuickItem *getSectionItem(int modelIndex, bool alreadyInserted);
169 QQuickItem *getSectionItem(const QString &sectionText);
171#if (QT_VERSION < QT_VERSION_CHECK(5, 1, 0))
172 QQuickVisualDataModel *m_delegateModel;
173#else
174 QQmlDelegateModel *m_delegateModel;
175#endif
177 // Index we are waiting because we requested it asynchronously
178 int m_asyncRequestedIndex;
180 // Used to only give a warning once if the delegate does not return objects
181 bool m_delegateValidated;
183 // Visible indexes, [0] is m_firstValidIndex, [0+1] is m_firstValidIndex +1, ...
184 QList<ListItem *> m_visibleItems;
185 int m_firstVisibleIndex;
187 qreal m_minYExtent;
189 QQuickItem *m_clipItem;
191 // If any of the heights has changed
192 // or new items have been added/removed
193 bool m_contentHeightDirty;
195 QQuickItem *m_headerItem;
196 qreal m_previousContentY;
197 qreal m_headerItemShownHeight; // The height of header shown when the header is shown outside its topmost position
198 // i.e. it's being shown after dragging down in the middle of the list
199 enum ContentYAnimationType { ContentYAnimationShowHeader, ContentYAnimationMaximizeVisibleArea };
200 ContentYAnimationType contentYAnimationType;
201 QQuickNumberAnimation *m_contentYAnimation;
203 QQmlComponent *m_sectionDelegate;
204 QString m_sectionProperty;
205 QQuickItem *m_topSectionItem;
207 bool m_forceNoClip;
208 bool m_inLayout;
209 bool m_inContentHeightKeepHeaderShown;
211 // Qt 5.0 doesn't like releasing the items just after itemCreated
212 // so we delay the releasing until the next updatePolish
213 QList<ListItem *> m_itemsToRelease;
214};
217#endif