Add Calendar to Qt Quick Controls.

Task-number: QTBUG-29948

[ChangeLog][QtQuickControls] Calendar was added. Calendar allows
selection of dates from a grid of days, similar to
QCalendarWidget.

Change-Id: I279130e704bc0dfd8dfe114ec9b6b49e111faf96
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>

1 files changed, 264 insertions, 0 deletions

diff --git a/src/controls/Private/qquickcalendarmodel.cpp b/src/controls/Private/qquickcalendarmodel.cpp
new file mode 100644
index 00000000..83c2885c
--- /dev/null
+++ b/src/controls/Private/qquickcalendarmodel.cpp
@@ -0,0 +1,264 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the Qt Quick Controls module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/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 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 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 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qquickcalendarmodel_p.h"
+
+namespace {
+    static const int daysInAWeek = 7;
+
+    /*
+        Not the number of weeks per month, but the number of weeks that are
+        shown on a typical calendar.
+    */
+    static const int weeksOnACalendarMonth = 6;
+
+    /*
+        The amount of days to populate the calendar with.
+    */
+    static const int daysOnACalendarMonth = daysInAWeek * weeksOnACalendarMonth;
+}
+
+QT_BEGIN_NAMESPACE
+
+/*!
+    QQuickCalendarModel provides a model for the Calendar control.
+    It is responsible for populating itself with dates based on a given month
+    and year.
+
+    The model stores a list of dates whose indices map directly to the Calendar.
+    For example, the model would store the following dates when any day in
+    January 2015 is selected on the Calendar:
+
+    [30/12/2014][31/12/2014][01/01/2015]...[31/01/2015][01/02/2015]...[09/02/2015]
+
+    The Calendar would then display the dates in the same order within a grid:
+
+            January 2015
+
+    [30][31][01][02][03][04][05]
+    [06][07][08][09][10][11][12]
+    [13][14][15][16][17][18][19]
+    [20][21][22][23][24][25][26]
+    [27][28][29][30][31][01][02]
+    [03][04][05][06][07][08][09]
+*/
+
+QQuickCalendarModel::QQuickCalendarModel(QObject *parent) :
+    QAbstractListModel(parent)
+{
+}
+
+/*!
+    The date that determines which dates are stored.
+
+    We store all of the days in the month of visibleDate, as well as any days
+    in the previous or following month if there is enough space.
+*/
+QDate QQuickCalendarModel::visibleDate() const
+{
+    return mVisibleDate;
+}
+
+/*!
+    Sets the visible date to \a visibleDate.
+
+    If \a visibleDate is a valid date and is different than the previously
+    visible date, the visible date is changed and
+    populateFromVisibleDate() called.
+*/
+void QQuickCalendarModel::setVisibleDate(const QDate &date)
+{
+    if (date != mVisibleDate && date.isValid()) {
+        const QDate previousDate = mVisibleDate;
+        mVisibleDate = date;
+        populateFromVisibleDate(previousDate);
+        emit visibleDateChanged(date);
+    }
+}
+
+/*!
+    The locale set on the Calendar.
+
+    This affects which dates are stored for visibleDate(). For example, if
+    the locale is en_US, the first day of the week is Sunday. Therefore, if
+    visibleDate() is some day in January 2014, there will be three days
+    displayed before the 1st of January:
+
+
+            January 2014
+
+    [SO][MO][TU][WE][TH][FR][SA]
+    [29][30][31][01][02][03][04]
+    ...
+
+    If the locale is then changed to en_GB (with the same visibleDate()),
+    there will be 2 days before the 1st of January, because Monday is the
+    first day of the week for that locale:
+
+            January 2014
+
+    [MO][TU][WE][TH][FR][SA][SO]
+    [30][31][01][02][03][04][05]
+    ...
+*/
+QLocale QQuickCalendarModel::locale() const
+{
+    return mLocale;
+}
+
+/*!
+    Sets the locale to \a locale.
+*/
+void QQuickCalendarModel::setLocale(const QLocale &locale)
+{
+    if (locale != mLocale) {
+        Qt::DayOfWeek previousFirstDayOfWeek = mLocale.firstDayOfWeek();
+        mLocale = locale;
+        emit localeChanged(mLocale);
+        if (mLocale.firstDayOfWeek() != previousFirstDayOfWeek) {
+            // We don't have a previousDate, so just use our current one...
+            // it's ignored anyway, since we're forcing the repopulation.
+            populateFromVisibleDate(mVisibleDate, true);
+        }
+    }
+}
+
+QVariant QQuickCalendarModel::data(const QModelIndex &index, int role) const
+{
+    if (role == DateRole)
+        return mVisibleDates.at(index.row());
+    return QVariant();
+}
+
+int QQuickCalendarModel::rowCount(const QModelIndex &) const
+{
+    return mVisibleDates.isEmpty() ? 0 : weeksOnACalendarMonth * daysInAWeek;
+}
+
+QHash<int, QByteArray> QQuickCalendarModel::roleNames() const
+{
+    QHash<int, QByteArray> names;
+    names[DateRole] = QByteArrayLiteral("date");
+    return names;
+}
+
+/*!
+    Returns the date at \a index, or an invalid date if \a index is invalid.
+*/
+QDate QQuickCalendarModel::dateAt(int index) const
+{
+    return index >= 0 && index < mVisibleDates.size() ? mVisibleDates.at(index) : QDate();
+}
+
+/*!
+    Returns the index for \a date, or -1 if \a date is outside of our range.
+*/
+int QQuickCalendarModel::indexAt(const QDate &date)
+{
+    if (mVisibleDates.size() == 0 || date < mFirstVisibleDate || date > mLastVisibleDate)
+        return -1;
+
+    // The index of the visible date will be the days from the
+    // previous month that we had to display before it, plus the
+    // day of the visible date itself.
+    return qMax(qint64(0), mFirstVisibleDate.daysTo(date));
+}
+
+/*!
+    Returns the week number for the first day of the week corresponding to \a row,
+    or -1 if \a row is outside of our range.
+*/
+int QQuickCalendarModel::weekNumberAt(int row) const
+{
+    const int index = row * daysInAWeek;
+    const QDate date = dateAt(index);
+    if (date.isValid())
+        return date.weekNumber();
+    return -1;
+}
+
+/*!
+    Called before visibleDateChanged() is emitted.
+
+    This function is called even when just the day has changed, in which case
+    it does nothing.
+
+    The \a force parameter is used when the locale has changed; the month
+    shown doesn't change, but the days displayed do.
+    The \a previousDate parameter is ignored when \a force is true.
+*/
+void QQuickCalendarModel::populateFromVisibleDate(const QDate &previousDate, bool force)
+{
+    // We don't need to populate if the year and month haven't changed.
+    if (!force && mVisibleDate.year() == previousDate.year() && mVisibleDate.month() == previousDate.month())
+        return;
+
+    // Since our model is of a fixed size, we fill it once and assign values each time
+    // the month changes, instead of clearing and appending each time.
+    bool isEmpty = mVisibleDates.isEmpty();
+    if (isEmpty) {
+        beginResetModel();
+        mVisibleDates.fill(QDate(), daysOnACalendarMonth);
+    }
+
+    // The actual first (1st) day of the month.
+    QDate firstDayOfMonthDate(mVisibleDate.year(), mVisibleDate.month(), 1);
+    int difference = ((firstDayOfMonthDate.dayOfWeek() - mLocale.firstDayOfWeek()) + 7) % 7;
+    // The first day to display should never be the 1st of the month, as we want some days from
+    // the previous month to be visible.
+    if (difference == 0)
+        difference += daysInAWeek;
+    QDate firstDateToDisplay = firstDayOfMonthDate.addDays(-difference);
+    for (int i = 0; i < daysOnACalendarMonth; ++i)
+        mVisibleDates[i] = firstDateToDisplay.addDays(i);
+
+    mFirstVisibleDate = mVisibleDates.at(0);
+    mLastVisibleDate = mVisibleDates.at(mVisibleDates.size() - 1);
+
+    if (!isEmpty) {
+        emit dataChanged(index(0, 0), index(rowCount() - 1, 0));
+    } else {
+        endResetModel();
+        emit countChanged(rowCount());
+    }
+}
+
+QT_END_NAMESPACE