XChinux |
2012-07-15 12:44 |
FlowLayout,从Qt Demo&Examples里提取出来的
从左向右自动布局,自动换行,这个很有用。 头文件FlowLayout.hpp
- #ifndef FLOWLAYOUT_HPP
#define FLOWLAYOUT_HPP
#include <QtCore> #include <QtGui>
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
CPP文件FlowLayout.cpp
- #include <QtGui>
#include "FlowLayout.hpp"
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(); } }
下面这个图是程序在960x600分辨率下自FlowLayout自适应每行显示4个产品的截图 [attachment=8604]
下面这个图是程序在1280x800分辨率下FlowLayout自适应每行显示5个产品的截图 [attachment=8605]
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