searchlineedit.cpp Example File

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  #include "searchlineedit.h"

  #include <QtGui/QPainter>
  #include <QtGui/QMouseEvent>
  #include <QtWidgets/QMenu>
  #include <QtWidgets/QStyle>
  #include <QtWidgets/QStyleOptionFrame>

  ClearButton::ClearButton(QWidget *parent)
    : QAbstractButton(parent)
  {
  #ifndef QT_NO_CURSOR
      setCursor(Qt::ArrowCursor);
  #endif // QT_NO_CURSOR
      setToolTip(tr("Clear"));
      setVisible(false);
      setFocusPolicy(Qt::NoFocus);
  }

  void ClearButton::paintEvent(QPaintEvent *event)
  {
      Q_UNUSED(event);
      QPainter painter(this);
      int height = this->height();

      painter.setRenderHint(QPainter::Antialiasing, true);
      painter.setBrush(isDown()
                       ? palette().color(QPalette::Dark)
                       : palette().color(QPalette::Mid));
      painter.setPen(painter.brush().color());
      int size = width();
      int offset = size / 5;
      int radius = size - offset * 2;
      painter.drawEllipse(offset, offset, radius, radius);

      painter.setPen(palette().color(QPalette::Base));
      int border = offset * 2;
      painter.drawLine(border, border, width() - border, height - border);
      painter.drawLine(border, height - border, width() - border, border);
  }

  void ClearButton::textChanged(const QString &text)
  {
      setVisible(!text.isEmpty());
  }

  /*
      Search icon on the left hand side of the search widget
      When a menu is set a down arrow appears
   */
  class SearchButton : public QAbstractButton {
  public:
      SearchButton(QWidget *parent = 0);
      void paintEvent(QPaintEvent *event);
      QMenu *m_menu;

  protected:
      void mousePressEvent(QMouseEvent *event);
  };

  SearchButton::SearchButton(QWidget *parent)
    : QAbstractButton(parent),
      m_menu(0)
  {
      setObjectName(QLatin1String("SearchButton"));
  #ifndef QT_NO_CURSOR
      setCursor(Qt::ArrowCursor);
  #endif //QT_NO_CURSOR
      setFocusPolicy(Qt::NoFocus);
  }

  void SearchButton::mousePressEvent(QMouseEvent *event)
  {
      if (m_menu && event->button() == Qt::LeftButton) {
          QWidget *p = parentWidget();
          if (p) {
              QPoint r = p->mapToGlobal(QPoint(0, p->height()));
              m_menu->exec(QPoint(r.x() + height() / 2, r.y()));
          }
          event->accept();
      }
      QAbstractButton::mousePressEvent(event);
  }

  void SearchButton::paintEvent(QPaintEvent *event)
  {
      Q_UNUSED(event);
      QPainterPath myPath;

      int radius = (height() / 5) * 2;
      QRect circle(height() / 3 - 1, height() / 4, radius, radius);
      myPath.addEllipse(circle);

      myPath.arcMoveTo(circle, 300);
      QPointF c = myPath.currentPosition();
      int diff = height() / 7;
      myPath.lineTo(qMin(width() - 2, (int)c.x() + diff), c.y() + diff);

      QPainter painter(this);
      painter.setRenderHint(QPainter::Antialiasing, true);
      painter.setPen(QPen(Qt::darkGray, 2));
      painter.drawPath(myPath);

      if (m_menu) {
          QPainterPath dropPath;
          dropPath.arcMoveTo(circle, 320);
          QPointF c = dropPath.currentPosition();
          c = QPointF(c.x() + 3.5, c.y() + 0.5);
          dropPath.moveTo(c);
          dropPath.lineTo(c.x() + 4, c.y());
          dropPath.lineTo(c.x() + 2, c.y() + 2);
          dropPath.closeSubpath();
          painter.setPen(Qt::darkGray);
          painter.setBrush(Qt::darkGray);
          painter.setRenderHint(QPainter::Antialiasing, false);
          painter.drawPath(dropPath);
      }
      painter.end();
  }

  /*
      SearchLineEdit is an enhanced QLineEdit
      - A Search icon on the left with optional menu
      - When there is no text and doesn't have focus an "inactive text" is displayed
      - When there is text a clear button is displayed on the right hand side
   */
  SearchLineEdit::SearchLineEdit(QWidget *parent) : ExLineEdit(parent),
      m_searchButton(new SearchButton(this))
  {
      connect(lineEdit(), SIGNAL(textChanged(QString)),
              this, SIGNAL(textChanged(QString)));
      setLeftWidget(m_searchButton);
      m_inactiveText = tr("Search");

      QSizePolicy policy = sizePolicy();
      setSizePolicy(QSizePolicy::Preferred, policy.verticalPolicy());
  }

  void SearchLineEdit::paintEvent(QPaintEvent *event)
  {
      if (lineEdit()->text().isEmpty() && !hasFocus() && !m_inactiveText.isEmpty()) {
          ExLineEdit::paintEvent(event);
          QStyleOptionFrame panel;
          initStyleOption(&panel);
          QRect r = style()->subElementRect(QStyle::SE_LineEditContents, &panel, this);
          QFontMetrics fm = fontMetrics();
          int horizontalMargin = lineEdit()->x();
          QRect lineRect(horizontalMargin + r.x(), r.y() + (r.height() - fm.height() + 1) / 2,
                         r.width() - 2 * horizontalMargin, fm.height());
          QPainter painter(this);
          painter.setPen(palette().brush(QPalette::Disabled, QPalette::Text).color());
          painter.drawText(lineRect, Qt::AlignLeft|Qt::AlignVCenter, m_inactiveText);
      } else {
          ExLineEdit::paintEvent(event);
      }
  }

  void SearchLineEdit::resizeEvent(QResizeEvent *event)
  {
      updateGeometries();
      ExLineEdit::resizeEvent(event);
  }

  void SearchLineEdit::updateGeometries()
  {
      int menuHeight = height();
      int menuWidth = menuHeight + 1;
      if (!m_searchButton->m_menu)
          menuWidth = (menuHeight / 5) * 4;
      m_searchButton->resize(QSize(menuWidth, menuHeight));
  }

  QString SearchLineEdit::inactiveText() const
  {
      return m_inactiveText;
  }

  void SearchLineEdit::setInactiveText(const QString &text)
  {
      m_inactiveText = text;
  }

  void SearchLineEdit::setMenu(QMenu *menu)
  {
      if (m_searchButton->m_menu)
          m_searchButton->m_menu->deleteLater();
      m_searchButton->m_menu = menu;
      updateGeometries();
  }

  QMenu *SearchLineEdit::menu() const
  {
      if (!m_searchButton->m_menu) {
          m_searchButton->m_menu = new QMenu(m_searchButton);
          if (isVisible())
              (const_cast<SearchLineEdit*>(this))->updateGeometries();
      }
      return m_searchButton->m_menu;
  }