问题
My question is basically the same as this one, but applied to the Qt C++ framework.
I am implementing a popup window by inheriting QWidget with flags Qt::QPopup | Qt::QWindow. I would like this window to be moveable and resizeable, I'm currently achieving this by using the mouse events in the following code:
void TextPopup::mousePressEvent(QMouseEvent* event)
{
offset = event->pos();
QWidget::mousePressEvent(event);
}
void TextPopup::mouseMoveEvent(QMouseEvent* event)
{
if(event->buttons() & Qt::LeftButton)
if(resizeMode) {
QPoint p = mapToGlobal(event->pos()) - geometry().topLeft();
resize(p.x(), p.y());
} else
move(mapToParent(event->pos() - offset));
else {
QPoint diff = geometry().bottomRight() - mapToGlobal(event->pos());
if(diff.x() <= 6 && diff.y() <= 6) {
if(!resizeMode) {
setCursor(Qt::SizeFDiagCursor);
resizeMode = true;
}
} else {
if(resizeMode) {
setCursor(Qt::SizeAllCursor);
resizeMode = false;
}
}
}
}
void TextPopup::mouseReleaseEvent(QMouseEvent* event)
{
offset = QPoint();
QWidget::mouseReleaseEvent(event);
}
I have a few problems with this. For one, I'm guessing there's a better way to do it. And more importantly, I would like the resize symbol at the bottom right as in this image] (taken from the post mentioned above). Any suggestions for achieving this?
回答1:
You can add the resize grip by calling QDialog's or QStatusBar's function setSizeGripEnabled (or directly in QtCreator form designer).
For custom widgets the simplest way probably is to use QSizeGrip. I didn't use it myself but you can check the Qt source code on git for QStatusBar or QDialog.
回答2:
If you don't want QSizeGrip you may take a look at this solution :
frameless.h:
#pragma once
#include <QtWidgets/QWidget>
#include <QtWidgets/QRubberBand>
#include <QtCore/QObject>
#include <QtCore/QEvent>
#include <QtCore/QRect>
#include <QtCore/QPoint>
#include <QtCore/Qt>
#include <QtGui/QHoverEvent>
#include <QtGui/QMouseEvent>
class FrameLess : public QObject {
Q_OBJECT
public:
enum Edge {
None = 0x0,
Left = 0x1,
Top = 0x2,
Right = 0x4,
Bottom = 0x8,
TopLeft = 0x10,
TopRight = 0x20,
BottomLeft = 0x40,
BottomRight = 0x80,
};
Q_ENUM(Edge);
Q_DECLARE_FLAGS(Edges, Edge);
FrameLess(QWidget *target);
void setBorderWidth(int w) {
_borderWidth = w;
}
int borderWidth() const {
return _borderWidth;
}
protected:
bool eventFilter(QObject *o, QEvent *e) override;
void mouseHover(QHoverEvent*);
void mouseLeave(QEvent*);
void mousePress(QMouseEvent*);
void mouseRealese(QMouseEvent*);
void mouseMove(QMouseEvent*);
void updateCursorShape(const QPoint &);
void calculateCursorPosition(const QPoint &, const QRect &, Edges &);
private:
QWidget *_target = nullptr;
QRubberBand *_rubberband = nullptr;
bool _cursorchanged;
bool _leftButtonPressed;
Edges _mousePress = Edge::None;
Edges _mouseMove = Edge::None;
int _borderWidth;
QPoint _dragPos;
bool _dragStart = false;
};
Q_DECLARE_OPERATORS_FOR_FLAGS(FrameLess::Edges);
frameless.cpp:
#include "frameless.h"
FrameLess::FrameLess(QWidget *target) :
_target(target),
_cursorchanged(false),
_leftButtonPressed(false),
_borderWidth(5),
_dragPos(QPoint())
{
_target->setMouseTracking(true);
_target->setWindowFlags(Qt::FramelessWindowHint);
_target->setAttribute(Qt::WA_Hover);
_target->installEventFilter(this);
_rubberband = new QRubberBand(QRubberBand::Rectangle);
}
bool FrameLess::eventFilter(QObject *o, QEvent*e) {
if (e->type() == QEvent::MouseMove ||
e->type() == QEvent::HoverMove ||
e->type() == QEvent::Leave ||
e->type() == QEvent::MouseButtonPress ||
e->type() == QEvent::MouseButtonRelease) {
switch (e->type()) {
case QEvent::MouseMove:
mouseMove(static_cast<QMouseEvent*>(e));
return true;
break;
case QEvent::HoverMove:
mouseHover(static_cast<QHoverEvent*>(e));
return true;
break;
case QEvent::Leave:
mouseLeave(e);
return true;
break;
case QEvent::MouseButtonPress:
mousePress(static_cast<QMouseEvent*>(e));
return true;
break;
case QEvent::MouseButtonRelease:
mouseRealese(static_cast<QMouseEvent*>(e));
return true;
break;
}
}
else {
return _target->eventFilter(o, e);
}
}
void FrameLess::mouseHover(QHoverEvent *e) {
updateCursorShape(_target->mapToGlobal(e->pos()));
}
void FrameLess::mouseLeave(QEvent *e) {
if (!_leftButtonPressed) {
_target->unsetCursor();
}
}
void FrameLess::mousePress(QMouseEvent *e) {
if (e->button() & Qt::LeftButton) {
_leftButtonPressed = true;
calculateCursorPosition(e->globalPos(), _target->frameGeometry(), _mousePress);
if (!_mousePress.testFlag(Edge::None)) {
_rubberband->setGeometry(_target->frameGeometry());
}
if (_target->rect().marginsRemoved(QMargins(borderWidth(), borderWidth(), borderWidth(), borderWidth())).contains(e->pos())) {
_dragStart = true;
_dragPos = e->pos();
}
}
}
void FrameLess::mouseRealese(QMouseEvent *e) {
if (e->button() & Qt::LeftButton) {
_leftButtonPressed = false;
_dragStart = false;
}
}
void FrameLess::mouseMove(QMouseEvent *e) {
if (_leftButtonPressed) {
if (_dragStart) {
_target->move(_target->frameGeometry().topLeft() + (e->pos() - _dragPos));
}
if (!_mousePress.testFlag(Edge::None)) {
int left = _rubberband->frameGeometry().left();
int top = _rubberband->frameGeometry().top();
int right = _rubberband->frameGeometry().right();
int bottom = _rubberband->frameGeometry().bottom();
switch (_mousePress) {
case Edge::Top:
top = e->globalPos().y();
break;
case Edge::Bottom:
bottom = e->globalPos().y();
break;
case Edge::Left:
left = e->globalPos().x();
break;
case Edge::Right:
right = e->globalPos().x();
break;
case Edge::TopLeft:
top = e->globalPos().y();
left = e->globalPos().x();
break;
case Edge::TopRight:
right = e->globalPos().x();
top = e->globalPos().y();
break;
case Edge::BottomLeft:
bottom = e->globalPos().y();
left = e->globalPos().x();
break;
case Edge::BottomRight:
bottom = e->globalPos().y();
right = e->globalPos().x();
break;
}
QRect newRect(QPoint(left, top), QPoint(right, bottom));
if (newRect.width() < _target->minimumWidth()) {
left = _target->frameGeometry().x();
}
else if (newRect.height() < _target->minimumHeight()) {
top = _target->frameGeometry().y();
}
_target->setGeometry(QRect(QPoint(left, top), QPoint(right, bottom)));
_rubberband->setGeometry(QRect(QPoint(left, top), QPoint(right, bottom)));
}
}
else {
updateCursorShape(e->globalPos());
}
}
void FrameLess::updateCursorShape(const QPoint &pos) {
if (_target->isFullScreen() || _target->isMaximized()) {
if (_cursorchanged) {
_target->unsetCursor();
}
return;
}
if (!_leftButtonPressed) {
calculateCursorPosition(pos, _target->frameGeometry(), _mouseMove);
_cursorchanged = true;
if (_mouseMove.testFlag(Edge::Top) || _mouseMove.testFlag(Edge::Bottom)) {
_target->setCursor(Qt::SizeVerCursor);
}
else if (_mouseMove.testFlag(Edge::Left) || _mouseMove.testFlag(Edge::Right)) {
_target->setCursor(Qt::SizeHorCursor);
}
else if (_mouseMove.testFlag(Edge::TopLeft) || _mouseMove.testFlag(Edge::BottomRight)) {
_target->setCursor(Qt::SizeFDiagCursor);
}
else if (_mouseMove.testFlag(Edge::TopRight) || _mouseMove.testFlag(Edge::BottomLeft)) {
_target->setCursor(Qt::SizeBDiagCursor);
}
else if (_cursorchanged) {
_target->unsetCursor();
_cursorchanged = false;
}
}
}
void FrameLess::calculateCursorPosition(const QPoint &pos, const QRect &framerect, Edges &_edge) {
bool onLeft = pos.x() >= framerect.x() - _borderWidth && pos.x() <= framerect.x() + _borderWidth &&
pos.y() <= framerect.y() + framerect.height() - _borderWidth && pos.y() >= framerect.y() + _borderWidth;
bool onRight = pos.x() >= framerect.x() + framerect.width() - _borderWidth && pos.x() <= framerect.x() + framerect.width() &&
pos.y() >= framerect.y() + _borderWidth && pos.y() <= framerect.y() + framerect.height() - _borderWidth;
bool onBottom = pos.x() >= framerect.x() + _borderWidth && pos.x() <= framerect.x() + framerect.width() - _borderWidth &&
pos.y() >= framerect.y() + framerect.height() - _borderWidth && pos.y() <= framerect.y() + framerect.height();
bool onTop = pos.x() >= framerect.x() + _borderWidth && pos.x() <= framerect.x() + framerect.width() - _borderWidth &&
pos.y() >= framerect.y() && pos.y() <= framerect.y() + _borderWidth;
bool onBottomLeft = pos.x() <= framerect.x() + _borderWidth && pos.x() >= framerect.x() &&
pos.y() <= framerect.y() + framerect.height() && pos.y() >= framerect.y() + framerect.height() - _borderWidth;
bool onBottomRight = pos.x() >= framerect.x() + framerect.width() - _borderWidth && pos.x() <= framerect.x() + framerect.width() &&
pos.y() >= framerect.y() + framerect.height() - _borderWidth && pos.y() <= framerect.y() + framerect.height();
bool onTopRight = pos.x() >= framerect.x() + framerect.width() - _borderWidth && pos.x() <= framerect.x() + framerect.width() &&
pos.y() >= framerect.y() && pos.y() <= framerect.y() + _borderWidth;
bool onTopLeft = pos.x() >= framerect.x() && pos.x() <= framerect.x() + _borderWidth &&
pos.y() >= framerect.y() && pos.y() <= framerect.y() + _borderWidth;
if (onLeft) {
_edge = Left;
}
else if (onRight) {
_edge = Right;
}
else if (onBottom) {
_edge = Bottom;
}
else if (onTop) {
_edge = Top;
}
else if (onBottomLeft) {
_edge = BottomLeft;
}
else if (onBottomRight) {
_edge = BottomRight;
}
else if (onTopRight) {
_edge = TopRight;
}
else if (onTopLeft) {
_edge = TopLeft;
}
else {
_edge = None;
}
}
And just create an instance and put your QWidget:
#include "frameless.h"
#include <QtWidgets/qapplication.h>
int main(int argc, char *argv[]) {
QApplication a(argc, argv);
QWidget *widget = new QWidget;
FrameLess f(widget);
widget->show();
return a.exec();
}
回答3:
You can use QSizeGrip in a layout inside your widget :
myWidget->setWindowFlags(Qt::SubWindow);
QSizeGrip * sizeGrip = new QSizeGrip(myWidget);
QGridLayout * layout = new QGridLayout(myWidget);
layout->addWidget(sizeGrip, 0,0,1,1,Qt::AlignBottom | Qt::AlignRight);
The QSizeGrip class provides a resize handle for resizing top-level windows. When you set the widget flag Qt::SubWindow, then the user can resize it using the size grip.
来源：https://stackoverflow.com/questions/5752408/qt-resize-borderless-widget