Текст в QLineEdit

[pupapum]

Всем добрый день.

Есть QLineEdit, в нем, по умолчанию, написано слово "Поиск", нужно, что бы при нажатии мышкой на QLineEdit текст исчезал, а в случае, если ничего не ввели и переключились на другие элементы управления, то слово "Поиск" вернулось. В общем как делается на сайтах и разных программах.

Подскажите, пожалуйста, в каком направлении копать, т.к. не понятно, как четко понимать, что мы ушли с QLineEdit.

Спасибо.

[Авварон]

void   QLineEdit::setPlaceholderText ( const QString & )

[SimpleSunny]

Или для более ранних версий focusInEvent, focusOutEvent.

[pupapum]

Смотрю help, там есть public function - void setPlaceholderText ( const QString & )
Пишу так:
findEdit->setPlaceholderText(QString::fromLocal8Bit("Поиск..."));

А он мне отвечает, что такой функции нет. В чем тут дело? 

[Авварон]

вы смотрите доку от одной версии, а используете другую?

[SimpleSunny]

Да они что-то спутали, наверное. Пишут, что вели в 4.7, а дока на 4.6.
http://doc.qt.nokia.com/4.6/qlineedit.html#placeholderText-prop

[pupapum]

Я SDK свежий выкачал и help их, может попутали.

Ладно, бог с ним. я через FocusIn и FocusOut сделал, только вот не задача, я когда мышкой щелкаю в QLineEdit, у меня курсор не появляется в нем ))

[SimpleSunny]

Вызовите вначала focusInEvent QLineEdit, а потом уже что-то свое делайте.
{
QLineEdit::focusInEvent(e);
...
}

[SABROG]

Посмотрите этот вариант, может быть пригодится.

[asvil]

Из исходных текстов qtcreator...
fancylineedit.h:

Код:

#ifndef FANCYLINEEDIT_H
#define FANCYLINEEDIT_H


#include <QtCore/QMetaType>
#include <QtGui/QLineEdit>

class FancyLineEditPrivate;

/* A line edit with an embedded pixmap on one side that is connected to
 * a menu. Additionally, it can display a grayed hintText (like "Type Here to")
 * when not focussed and empty. When connecting to the changed signals and
 * querying text, one has to be aware that the text is set to that hint
 * text if isShowingHintText() returns true (that is, does not contain
 * valid user input).
 */
class FancyLineEdit : public QLineEdit
{
		Q_DISABLE_COPY(FancyLineEdit)
		Q_OBJECT
		Q_ENUMS(Side)
		Q_PROPERTY(QPixmap pixmap READ pixmap WRITE setPixmap DESIGNABLE true)
		Q_PROPERTY(Side side READ side WRITE setSide DESIGNABLE isSideStored STORED isSideStored)
		Q_PROPERTY(bool useLayoutDirection READ useLayoutDirection WRITE setUseLayoutDirection DESIGNABLE true)
		Q_PROPERTY(bool menuTabFocusTrigger READ hasMenuTabFocusTrigger WRITE setMenuTabFocusTrigger  DESIGNABLE true)
		Q_PROPERTY(QString hintText READ hintText WRITE setHintText DESIGNABLE true)

public:
		enum Side {Left, Right};

		explicit FancyLineEdit(QWidget *parent = 0);
		~FancyLineEdit();

		QPixmap pixmap() const;

		void setMenu(QMenu *menu);
		QMenu *menu() const;

		void setSide(Side side);
		Side side() const;

		bool useLayoutDirection() const;
		void setUseLayoutDirection(bool v);

		// Set whether tabbing in will trigger the menu.
		bool hasMenuTabFocusTrigger() const;
		void setMenuTabFocusTrigger(bool v);

		// Hint text that is displayed when no focus is set.
		QString hintText() const;

		bool isShowingHintText() const;

		// Convenience for accessing the text that returns "" in case of isShowingHintText().
		QString typedText() const;

public slots:
		void setPixmap(const QPixmap &pixmap);
		void setHintText(const QString &ht);
		void showHintText();
		void hideHintText();

protected:
		virtual void resizeEvent(QResizeEvent *e);
		virtual void focusInEvent(QFocusEvent *e);
		virtual void focusOutEvent(QFocusEvent *e);

private:
		bool isSideStored() const;
		void updateMenuLabel();
		void positionMenuLabel();
		void updateStyleSheet(Side side);

		FancyLineEditPrivate *m_d;
};

#endif // FANCYLINEEDIT_H

fancylineedit.cpp

Код:

#include "fancylineedit.h"

#include <QtCore/QEvent>
#include <QtCore/QDebug>
#include <QtCore/QString>
#include <QtGui/QApplication>
#include <QtGui/QMenu>
#include <QtGui/QMouseEvent>
#include <QtGui/QLabel>

enum { margin = 6 };

static inline QString sideToStyleSheetString(FancyLineEdit::Side side)
{
		return side == FancyLineEdit::Left ? QLatin1String("left") : QLatin1String("right");
}

// Format style sheet for the label containing the pixmap. It has a margin on
// the outer side of the whole FancyLineEdit.
static QString labelStyleSheet(FancyLineEdit::Side side)
{
		QString rc = QLatin1String("QLabel { margin-");
		rc += sideToStyleSheetString(side);
		rc += QLatin1String(": ");
		rc += QString::number(margin);
		rc += QLatin1Char('}');
		return rc;
}

// --------- FancyLineEditPrivate as QObject with label
//           event filter

class FancyLineEditPrivate : public QObject {
public:
		explicit FancyLineEditPrivate(QLineEdit *parent);

		virtual bool eventFilter(QObject *obj, QEvent *event);

		const QString m_leftLabelStyleSheet;
		const QString m_rightLabelStyleSheet;

		QLineEdit *m_lineEdit;
		QPixmap m_pixmap;
		QMenu *m_menu;
		QLabel *m_menuLabel;
		FancyLineEdit::Side m_side;
		bool m_useLayoutDirection;
		bool m_menuTabFocusTrigger;
		QString m_hintText;
		bool m_showingHintText;
};


FancyLineEditPrivate::FancyLineEditPrivate(QLineEdit *parent) :
		QObject(parent),
		m_leftLabelStyleSheet(labelStyleSheet(FancyLineEdit::Left)),
		m_rightLabelStyleSheet(labelStyleSheet(FancyLineEdit::Right)),
		m_lineEdit(parent),
		m_menu(0),
		m_menuLabel(0),
		m_side(FancyLineEdit::Left),
		m_useLayoutDirection(false),
		m_menuTabFocusTrigger(false),
		m_showingHintText(false)
{
}

bool FancyLineEditPrivate::eventFilter(QObject *obj, QEvent *event)
{
		if (!m_menu || obj != m_menuLabel)
				return QObject::eventFilter(obj, event);

		switch (event->type()) {
		case QEvent::MouseButtonPress: {
				const QMouseEvent *me = static_cast<QMouseEvent *>(event);
				m_menu->exec(me->globalPos());
				return true;
		}
		case QEvent::FocusIn:
				if (m_menuTabFocusTrigger) {
						m_lineEdit->setFocus();
						m_menu->exec(m_menuLabel->mapToGlobal(m_menuLabel->rect().center()));
						return true;
				}
		default:
				break;
		}
		return QObject::eventFilter(obj, event);
}

// --------- FancyLineEdit
FancyLineEdit::FancyLineEdit(QWidget *parent) :
		QLineEdit(parent),
		m_d(new FancyLineEditPrivate(this))
{
		m_d->m_menuLabel = new QLabel(this);
		m_d->m_menuLabel->installEventFilter(m_d);
		updateMenuLabel();
		showHintText();
}

FancyLineEdit::~FancyLineEdit()
{
}

// Position the menu label left or right according to size.
// Called when switching side and from resizeEvent.
void FancyLineEdit::positionMenuLabel()
{
		switch (side()) {
		case Left:
				m_d->m_menuLabel->setGeometry(0, 0, m_d->m_pixmap.width()+margin, height());
				break;
		case Right:
				m_d->m_menuLabel->setGeometry(width() - m_d->m_pixmap.width() - margin, 0,
																			m_d->m_pixmap.width()+margin, height());
				break;
		}
}

void FancyLineEdit::updateStyleSheet(Side side)
{
		// Udate the LineEdit style sheet. Make room for the label on the
		// respective side and set color according to whether we are showing the
		// hint text
		QString sheet = QLatin1String("QLineEdit{ padding-");
		sheet += sideToStyleSheetString(side);
		sheet += QLatin1String(": ");
		sheet += QString::number(m_d->m_pixmap.width() + margin);
		sheet += QLatin1Char(';');
		if (m_d->m_showingHintText)
				sheet += QLatin1String(" color: #BBBBBB;");
		sheet += QLatin1Char('}');
		setStyleSheet(sheet);
}

void FancyLineEdit::updateMenuLabel()
{
		m_d->m_menuLabel->setPixmap(m_d->m_pixmap);
		const Side s = side();
		switch (s) {
		case Left:
				m_d->m_menuLabel->setAlignment(Qt::AlignVCenter | Qt::AlignLeft);
				m_d->m_menuLabel->setStyleSheet(m_d->m_leftLabelStyleSheet);
				break;
		case Right:
				m_d->m_menuLabel->setAlignment(Qt::AlignVCenter | Qt::AlignRight);
				m_d->m_menuLabel->setStyleSheet(m_d->m_rightLabelStyleSheet);
				break;
		}
		updateStyleSheet(s);
		positionMenuLabel();
}

void FancyLineEdit::setSide(Side side)
{
		m_d->m_side = side;
		updateMenuLabel();
}

FancyLineEdit::Side FancyLineEdit::side() const
{
		if (m_d->m_useLayoutDirection)
				return qApp->layoutDirection() == Qt::LeftToRight ? Left : Right;
		return  m_d->m_side;
}

void FancyLineEdit::resizeEvent(QResizeEvent *)
{
		positionMenuLabel();
}

void FancyLineEdit::setPixmap(const QPixmap &pixmap)
{
		m_d->m_pixmap = pixmap;
		updateMenuLabel();
}

QPixmap FancyLineEdit::pixmap() const
{
		return m_d->m_pixmap;
}

void FancyLineEdit::setMenu(QMenu *menu)
{
		 m_d->m_menu = menu;
}

QMenu *FancyLineEdit::menu() const
{
		return  m_d->m_menu;
}

bool FancyLineEdit::useLayoutDirection() const
{
		return m_d->m_useLayoutDirection;
}

void FancyLineEdit::setUseLayoutDirection(bool v)
{
		m_d->m_useLayoutDirection = v;
}

bool FancyLineEdit::isSideStored() const
{
		return !m_d->m_useLayoutDirection;
}

bool FancyLineEdit::hasMenuTabFocusTrigger() const
{
		return m_d->m_menuTabFocusTrigger;
}

void FancyLineEdit::setMenuTabFocusTrigger(bool v)
{
		if (m_d->m_menuTabFocusTrigger == v)
				return;

		m_d->m_menuTabFocusTrigger = v;
		m_d->m_menuLabel->setFocusPolicy(v ? Qt::TabFocus : Qt::NoFocus);
}

QString FancyLineEdit::hintText() const
{
		return m_d->m_hintText;
}

void FancyLineEdit::setHintText(const QString &ht)
{
		// Updating magic to make the property work in Designer.
		if (ht == m_d->m_hintText)
				return;
		hideHintText();
		m_d->m_hintText = ht;
		if (!hasFocus() && !ht.isEmpty())
				showHintText();
}

void FancyLineEdit::showHintText()
{
		if (!m_d->m_showingHintText && text().isEmpty() && !m_d->m_hintText.isEmpty()) {
				m_d->m_showingHintText = true;
				setText(m_d->m_hintText);
				updateStyleSheet(side());
		}
}

void FancyLineEdit::hideHintText()
{
		if (m_d->m_showingHintText && !m_d->m_hintText.isEmpty()) {
				m_d->m_showingHintText = false;
				setText(QString());
				updateStyleSheet(side());
		}
}

void FancyLineEdit::focusInEvent(QFocusEvent *e)
{
		hideHintText();
		QLineEdit::focusInEvent(e);
}

void FancyLineEdit::focusOutEvent(QFocusEvent *e)
{
		// Focus out: Switch to displaying the hint text unless
		// there is user input
		showHintText();
		QLineEdit::focusOutEvent(e);
}

bool FancyLineEdit::isShowingHintText() const
{
		return m_d->m_showingHintText;
}

QString FancyLineEdit::typedText() const
{
		return m_d->m_showingHintText ? QString() : text();
}

[pupapum]

Люди!! Вы просто гуру! спасибо большое всем за помощь, исходник Creator'a вообще помог, сразу все заработало. УРА! =)