extends QLayout to create flow layout
/**************************************************************************** ** ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). ** All rights reserved. ** Contact: Nokia Corporation (qt-info@nokia.com) ** ** This file is part of the examples of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL$ ** Commercial Usage ** Licensees holding valid Qt Commercial licenses may use this file in ** accordance with the Qt Commercial License Agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and Nokia. ** ** 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, Nokia gives you certain additional ** rights. These rights are described in the Nokia 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. ** ** If you have questions regarding the use of this file, please contact ** Nokia at qt-info@nokia.com. ** $QT_END_LICENSE$ ** ****************************************************************************/ #ifndef FLOWLAYOUT_H #define FLOWLAYOUT_H #include <QLayout> #include <QRect> #include <QWidgetItem> class FlowLayout : public QLayout { public: FlowLayout(QWidget *parent, int margin = -1, int hSpacing = -1, int vSpacing = -1); FlowLayout(int margin = -1, int hSpacing = -1, int vSpacing = -1); ~FlowLayout(); void addItem(QLayoutItem *item); int horizontalSpacing() const; int verticalSpacing() const; Qt::Orientations expandingDirections() const; bool hasHeightForWidth() const; int heightForWidth(int) const; int count() const; QLayoutItem *itemAt(int index) const; QSize minimumSize() const; void setGeometry(const QRect &rect); QSize sizeHint() const; QLayoutItem *takeAt(int index); private: int doLayout(const QRect &rect, bool testOnly) const; int smartSpacing(QStyle::PixelMetric pm) const; QList<QLayoutItem *> itemList; int m_hSpace; int m_vSpace; }; #endif #include <QtGui> #include "flowlayout.h" FlowLayout::FlowLayout(QWidget *parent, int margin, int hSpacing, int vSpacing) : QLayout(parent), m_hSpace(hSpacing), m_vSpace(vSpacing) { setContentsMargins(margin, margin, margin, margin); } FlowLayout::FlowLayout(int margin, int hSpacing, int vSpacing) : m_hSpace(hSpacing), m_vSpace(vSpacing) { setContentsMargins(margin, margin, margin, margin); } FlowLayout::~FlowLayout() { QLayoutItem *item; while ((item = takeAt(0))) delete item; } void FlowLayout::addItem(QLayoutItem *item) { itemList.append(item); } int FlowLayout::horizontalSpacing() const { if (m_hSpace >= 0) { return m_hSpace; } else { return smartSpacing(QStyle::PM_LayoutHorizontalSpacing); } } int FlowLayout::verticalSpacing() const { if (m_vSpace >= 0) { return m_vSpace; } else { return smartSpacing(QStyle::PM_LayoutVerticalSpacing); } } int FlowLayout::count() const { return itemList.size(); } QLayoutItem *FlowLayout::itemAt(int index) const { return itemList.value(index); } QLayoutItem *FlowLayout::takeAt(int index) { if (index >= 0 && index < itemList.size()) return itemList.takeAt(index); else return 0; } Qt::Orientations FlowLayout::expandingDirections() const { return 0; } bool FlowLayout::hasHeightForWidth() const { return true; } int FlowLayout::heightForWidth(int width) const { int height = doLayout(QRect(0, 0, width, 0), true); return height; } void FlowLayout::setGeometry(const QRect &rect) { QLayout::setGeometry(rect); doLayout(rect, false); } QSize FlowLayout::sizeHint() const { return minimumSize(); } QSize FlowLayout::minimumSize() const { QSize size; QLayoutItem *item; foreach (item, itemList) size = size.expandedTo(item->minimumSize()); size += QSize(2*margin(), 2*margin()); return size; } int FlowLayout::doLayout(const QRect &rect, bool testOnly) const { int left, top, right, bottom; getContentsMargins(&left, &top, &right, &bottom); QRect effectiveRect = rect.adjusted(+left, +top, -right, -bottom); int x = effectiveRect.x(); int y = effectiveRect.y(); int lineHeight = 0; QLayoutItem *item; foreach (item, itemList) { QWidget *wid = item->widget(); int spaceX = horizontalSpacing(); if (spaceX == -1) spaceX = wid->style()->layoutSpacing( QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Horizontal); int spaceY = verticalSpacing(); if (spaceY == -1) spaceY = wid->style()->layoutSpacing( QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Vertical); int nextX = x + item->sizeHint().width() + spaceX; if (nextX - spaceX > effectiveRect.right() && lineHeight > 0) { x = effectiveRect.x(); y = y + lineHeight + spaceY; nextX = x + item->sizeHint().width() + spaceX; lineHeight = 0; } if (!testOnly) item->setGeometry(QRect(QPoint(x, y), item->sizeHint())); x = nextX; lineHeight = qMax(lineHeight, item->sizeHint().height()); } return y + lineHeight - rect.y() + bottom; } int FlowLayout::smartSpacing(QStyle::PixelMetric pm) const { QObject *parent = this->parent(); if (!parent) { return -1; } else if (parent->isWidgetType()) { QWidget *pw = static_cast<QWidget *>(parent); return pw->style()->pixelMetric(pm, 0, pw); } else { return static_cast<QLayout *>(parent)->spacing(); } } #ifndef WINDOW_H #define WINDOW_H #include <QWidget> QT_BEGIN_NAMESPACE class QLabel; QT_END_NAMESPACE class Window : public QWidget { Q_OBJECT public: Window(); }; #endif #include <QtGui> #include "flowlayout.h" #include "window.h" Window::Window() { FlowLayout *flowLayout = new FlowLayout; flowLayout->addWidget(new QPushButton(tr("Short"))); flowLayout->addWidget(new QPushButton(tr("Longer"))); flowLayout->addWidget(new QPushButton(tr("Different text"))); flowLayout->addWidget(new QPushButton(tr("More text"))); flowLayout->addWidget(new QPushButton(tr("Even longer button text"))); setLayout(flowLayout); setWindowTitle(tr("Flow Layout")); } #include <QApplication> #include "window.h" int main(int argc, char *argv[]) { QApplication app(argc, argv); Window window; window.show(); return app.exec(); }
1. | extends QLayout to create border layout |