aboutsummaryrefslogtreecommitdiffstats
path: root/src/quickcontrols2/qquicktumblerview.cpp
blob: 5f5c065d2fc0ceb1f8ffbbb493debd5bc9697361 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
/****************************************************************************
**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the Qt Quick Controls 2 module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL3$
** Commercial License Usage
** Licensees holding valid commercial Qt 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 http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPLv3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or later as published by the Free
** Software Foundation and appearing in the file LICENSE.GPL included in
** the packaging of this file. Please review the following information to
** ensure the GNU General Public License version 2.0 requirements will be
** met: http://www.gnu.org/licenses/gpl-2.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qquicktumblerview_p.h"

#include <QtCore/qloggingcategory.h>
#include <QtQuick/private/qquickitem_p.h>
#include <QtQuick/private/qquicklistview_p.h>
#include <QtQuick/private/qquickpathview_p.h>

#include <QtQuickTemplates2/private/qquicktumbler_p.h>
#include <QtQuickTemplates2/private/qquicktumbler_p_p.h>

QT_BEGIN_NAMESPACE

Q_LOGGING_CATEGORY(lcTumblerView, "qt.quick.controls.tumblerview")

QQuickTumblerView::QQuickTumblerView(QQuickItem *parent) :
    QQuickItem(parent)
{
    // We don't call createView() here because we don't know what the wrap flag is set to
    // yet, and we don't want to create a view that might never get used.
}

QVariant QQuickTumblerView::model() const
{
    return m_model;
}

void QQuickTumblerView::setModel(const QVariant &model)
{
    qCDebug(lcTumblerView) << "setting model to:" << model << "on"
        << (m_pathView ? static_cast<QObject*>(m_pathView) : static_cast<QObject*>(m_listView));
    if (model == m_model)
        return;

    m_model = model;

    if (m_pathView) {
        m_pathView->setModel(m_model);
    } else if (m_listView) {
        // QQuickItemView::setModel() resets the current index,
        // but if we're still creating the Tumbler, it should be maintained.
        const int oldCurrentIndex = m_listView->currentIndex();
        m_listView->setModel(m_model);
        if (!isComponentComplete())
            m_listView->setCurrentIndex(oldCurrentIndex);
    }

    emit modelChanged();
}

QQmlComponent *QQuickTumblerView::delegate() const
{
    return m_delegate;
}

void QQuickTumblerView::setDelegate(QQmlComponent *delegate)
{
    qCDebug(lcTumblerView) << "setting delegate to:" << delegate << "on"
        << (m_pathView ? static_cast<QObject*>(m_pathView) : static_cast<QObject*>(m_listView));
    if (delegate == m_delegate)
        return;

    m_delegate = delegate;

    if (m_pathView)
        m_pathView->setDelegate(m_delegate);
    else if (m_listView)
        m_listView->setDelegate(m_delegate);

    emit delegateChanged();
}

QQuickPath *QQuickTumblerView::path() const
{
    return m_path;
}

void QQuickTumblerView::setPath(QQuickPath *path)
{
    if (path == m_path)
        return;

    m_path = path;
    emit pathChanged();
}

void QQuickTumblerView::createView()
{
    Q_ASSERT(m_tumbler);

    // We create a view regardless of whether or not we know
    // the count yet, because we rely on the view to tell us the count.
    if (m_tumbler->wrap()) {
        if (m_listView) {
            // It's necessary to call deleteLater() rather than delete,
            // as this code is most likely being run in rensponse to a signal
            // emission somewhere in the list view's internals, so we need to
            // wait until that has finished.
            m_listView->deleteLater();
            QQml_setParent_noEvent(m_listView, nullptr);
            // The auto tests pass with unparenting the list view alone, but
            // just to be sure, we unset some other things as well.
            m_listView->setParentItem(nullptr);
            m_listView->setVisible(false);
            m_listView->setModel(QVariant());
            m_listView = nullptr;
        }

        if (!m_pathView) {
            qCDebug(lcTumblerView) << "creating PathView";

            m_pathView = new QQuickPathView;
            QQmlEngine::setContextForObject(m_pathView, qmlContext(this));
            QQml_setParent_noEvent(m_pathView, this);
            m_pathView->setParentItem(this);
            m_pathView->setPath(m_path);
            m_pathView->setDelegate(m_delegate);
            m_pathView->setPreferredHighlightBegin(0.5);
            m_pathView->setPreferredHighlightEnd(0.5);
            m_pathView->setHighlightMoveDuration(1000);
            m_pathView->setClip(true);

            // Give the view a size.
            updateView();
            // Set the model.
            updateModel();

            qCDebug(lcTumblerView) << "finished creating PathView";
        }
    } else {
        if (m_pathView) {
            m_pathView->deleteLater();
            QQml_setParent_noEvent(m_pathView, nullptr);
            m_pathView->setParentItem(nullptr);
            m_pathView->setVisible(false);
            m_pathView->setModel(QVariant());
            m_pathView = nullptr;
        }

        if (!m_listView) {
            qCDebug(lcTumblerView) << "creating ListView";

            m_listView = new QQuickListView;
            QQmlEngine::setContextForObject(m_listView, qmlContext(this));
            QQml_setParent_noEvent(m_listView, this);
            m_listView->setParentItem(this);
            m_listView->setSnapMode(QQuickListView::SnapToItem);
            m_listView->setHighlightRangeMode(QQuickListView::StrictlyEnforceRange);
            m_listView->setClip(true);

            // Give the view a size.
            updateView();
            // Set the model.
            updateModel();

            // Set these after the model is set so that the currentItem animation
            // happens instantly on startup/after switching models. If we set them too early,
            // the view animates any potential currentIndex change over one second,
            // which we don't want when the contentItem has just been created.
            m_listView->setDelegate(m_delegate);
            m_listView->setHighlightMoveDuration(1000);

            qCDebug(lcTumblerView) << "finished creating ListView";
        }
    }
}

// Called whenever the size or visibleItemCount changes.
void QQuickTumblerView::updateView()
{
    QQuickItem *theView = view();
    if (!theView)
        return;

    theView->setSize(QSizeF(width(), height()));

    // Can be called in geometryChanged when it might not have a parent item yet.
    if (!m_tumbler)
        return;

    // Set view-specific properties that have a dependency on the size, etc.
    if (m_pathView) {
        m_pathView->setPathItemCount(m_tumbler->visibleItemCount() + 1);
        m_pathView->setDragMargin(width() / 2);
    } else {
        m_listView->setPreferredHighlightBegin(height() / 2 - (height() / m_tumbler->visibleItemCount() / 2));
        m_listView->setPreferredHighlightEnd(height() / 2 + (height() / m_tumbler->visibleItemCount() / 2));
    }
}

void QQuickTumblerView::updateModel()
{
    if (m_pathView && !m_pathView->model().isValid() && m_model.isValid()) {
        // QQuickPathView::setPathItemCount() resets the offset animation,
        // so we just skip the animation while constructing the view.
        const int oldHighlightMoveDuration = m_pathView->highlightMoveDuration();
        m_pathView->setHighlightMoveDuration(0);

        // Setting model can change the count, which can affect the wrap, which can cause
        // the current view to be deleted before setModel() is finished, which causes a crash.
        // Since QQuickTumbler can't know about QQuickTumblerView, we use its private API to
        // inform it that it should delay setting wrap.
        QQuickTumblerPrivate *tumblerPrivate = QQuickTumblerPrivate::get(m_tumbler);
        tumblerPrivate->beginSetModel();
        m_pathView->setModel(m_model);
        tumblerPrivate->endSetModel();

        // The count-depends-on-wrap behavior could cause wrap to change after
        // the call above, so we must check that we're still using a PathView.
        if (m_pathView)
            m_pathView->setHighlightMoveDuration(oldHighlightMoveDuration);
    } else if (m_listView && !m_listView->model().isValid() && m_model.isValid()) {
        const int currentIndex = m_tumbler->currentIndex();
        QQuickTumblerPrivate *tumblerPrivate = QQuickTumblerPrivate::get(m_tumbler);

        // setModel() causes QQuickTumblerPrivate::_q_onViewCountChanged() to
        // be called, which calls QQuickTumbler::setCurrentIndex(),
        // which results in QQuickItemViewPrivate::createHighlightItem() being
        // called. When the highlight item is created,
        // QQuickTumblerPrivate::itemChildAdded() is notified and
        // QQuickTumblerPrivate::_q_updateItemHeights() is called, which causes
        // a geometry change in the item and createHighlight() is called again.
        // However, since the highlight item hadn't been assigned yet in the
        // previous call frame, the "if (highlight) { delete highlight; }"
        // check doesn't succeed, so the item is never deleted.
        //
        // To avoid this, we tell QQuickTumblerPrivate to ignore signals while
        // setting the model, and manually call _q_onViewCountChanged() to
        // ensure the correct sequence of calls happens (_q_onViewCountChanged()
        // has to be within the ignoreSignals scope, because it also generates
        // recursion otherwise).
        tumblerPrivate->ignoreSignals = true;
        m_listView->setModel(m_model);
        m_listView->setCurrentIndex(currentIndex);

        tumblerPrivate->_q_onViewCountChanged();
        tumblerPrivate->ignoreSignals = false;
    }
}

void QQuickTumblerView::geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry)
{
    QQuickItem::geometryChanged(newGeometry, oldGeometry);
    updateView();
}

void QQuickTumblerView::componentComplete()
{
    QQuickItem::componentComplete();
    updateView();
}

void QQuickTumblerView::itemChange(QQuickItem::ItemChange change, const QQuickItem::ItemChangeData &data)
{
    QQuickItem::itemChange(change, data);

    if (change == QQuickItem::ItemParentHasChanged && data.item) {
        if (m_tumbler)
            m_tumbler->disconnect(this);

        m_tumbler = qobject_cast<QQuickTumbler*>(parentItem());

        if (m_tumbler) {
            // We assume that the parentChanged() signal of the tumbler will be emitted before its wrap property is set...
            connect(m_tumbler, &QQuickTumbler::wrapChanged, this, &QQuickTumblerView::createView);
            connect(m_tumbler, &QQuickTumbler::visibleItemCountChanged, this, &QQuickTumblerView::updateView);
        }
    }
}

QQuickItem *QQuickTumblerView::view()
{
    if (!m_tumbler)
        return nullptr;

    if (m_tumbler->wrap())
        return m_pathView;

    return m_listView;
}

QT_END_NAMESPACE