[Qt]不带标题栏（FramelessWindowHint）的窗体移动及调整大小

Qt窗体若设置了

setWindowFlags (Qt::FramelessWindowHint);

运行后该窗体是无法进行移动和调整大小的，那要如何才能让它和普通窗体一样进行移动和调整其大小的呢？方案如下：

void QFramelessWindow::mousePressEvent(QMouseEvent *event)

{

if (event->button() == Qt::LeftButton) {

this->m_drag = true;

this->dragPos = event->pos();

this->resizeDownPos = event->globalPos();

this->mouseDownRect = this->rect();

}

}

void QFramelessWindow::mouseMoveEvent(QMouseEvent * event)

{

if (resizeRegion != Default)

{

handleResize();

return;

}

if(m_move) {

move(event->globalPos() - dragPos);

return;

}

QPoint clientCursorPos = event->pos();

QRect r = this->rect();

QRect resizeInnerRect(resizeBorderWidth, resizeBorderWidth, r.width() - 2*resizeBorderWidth, r.height() - 2*resizeBorderWidth);

if(r.contains(clientCursorPos) && !resizeInnerRect.contains(clientCursorPos)) { //调整窗体大小

ResizeRegion resizeReg = getResizeRegion(clientCursorPos);

setResizeCursor(resizeReg);

if (m_drag && (event->buttons() & Qt::LeftButton)) {

resizeRegion = resizeReg;

    handleResize();

}

}

else { //移动窗体

setCursor(Qt::ArrowCursor);

if (m_drag && (event->buttons() & Qt::LeftButton)) {

m_move = true;

    move(event->globalPos() - dragPos);

}

}

}

void QFramelessWindow::mouseReleaseEvent(QMouseEvent *event)

{

m_drag = false;

if(m_move) {

m_move = false;

handleMove(event->globalPos()); //鼠标放开后若超出屏幕区域自动吸附于屏幕顶部/左侧/右侧

}

resizeRegion = Default;

setCursor(Qt::ArrowCursor);

}

void QFramelessWindow::setResizeCursor(ResizeRegion region)

{

switch (region)

{

case North:

case South:

setCursor(Qt::SizeVerCursor);

break;

case East:

case West:

setCursor(Qt::SizeHorCursor);

break;

case NorthWest:

case SouthEast:

setCursor(Qt::SizeFDiagCursor);

break;

default:

setCursor(Qt::SizeBDiagCursor);

break;

}

}

ResizeRegion QFramelessWindow::getResizeRegion(QPoint clientPos)

{

if (clientPos.y() <= resizeBorderWidth) {

if (clientPos.x() <= resizeBorderWidth)

return NorthWest;

else if (clientPos.x() >= this->width() - resizeBorderWidth)

return NorthEast;

else

return North;

}

else if (clientPos.y() >= this->height() - resizeBorderWidth) {

if (clientPos.x() <= resizeBorderWidth)

return SouthWest;

else if (clientPos.x() >= this->width() - resizeBorderWidth)

return SouthEast;

else

return South;

}

else {

if (clientPos.x() <= resizeBorderWidth)

return West;

else

return East;

}

}

void QFramelessWindow::handleMove(QPoint pt)

{

QPoint currentPos = pt - dragPos;

if(currentPos.x()<desktop->x()) { //吸附于屏幕左侧

currentPos.setX(desktop->x());

}

else if (currentPos.x()+this->width()>desktop->width()) { //吸附于屏幕右侧

currentPos.setX(desktop->width()-this->width());

}

if(currentPos.y()<desktop->y()) { //吸附于屏幕顶部

currentPos.setY(desktop->y());

}

move(currentPos);

}

void QFramelessWindow::handleResize()

{

int xdiff = QCursor::pos().x() - resizeDownPos.x();

int ydiff = QCursor::pos().y() - resizeDownPos.y();

switch (resizeRegion)

{

case East:

{

resize(mouseDownRect.width()+xdiff, this->height());

break;

}

case West:

{

resize(mouseDownRect.width()-xdiff, this->height());

move(resizeDownPos.x()+xdiff, this->y());

break;

}

case South:

{

resize(this->width(),mouseDownRect.height()+ydiff);

break;

}

case North:

{

resize(this->width(),mouseDownRect.height()-ydiff);

move(this->x(), resizeDownPos.y()+ydiff);

break;

}

case SouthEast:

{

resize(mouseDownRect.width() + xdiff, mouseDownRect.height() + ydiff);

break;

}

case NorthEast:

{

resize(mouseDownRect.width()+xdiff, mouseDownRect.height()-ydiff);

move(this->x(), resizeDownPos.y()+ydiff);

break;

}

case NorthWest:

{

resize(mouseDownRect.width()-xdiff, mouseDownRect.height()-ydiff);

move(resizeDownPos.x()+xdiff, resizeDownPos.y()+ydiff);

break;

}

case SouthWest:

{

resize(mouseDownRect.width()-xdiff, mouseDownRect.height()+ydiff);

move(resizeDownPos.x()+xdiff, this->y());

break;

}

}

}

本文的方案还附加了一个自动吸附功能，各位如果不需要的话，可以移除。

附上全局枚举及变量：

enum ResizeRegion

{

Default,

North,

NorthEast,

East,

SouthEast,

South,

SouthWest,

West,

NorthWest

};

bool m_drag, m_move;

QPoint dragPos, resizeDownPos;

const int resizeBorderWidth = 5;

ResizeRegion resizeRegion;

QRect mouseDownRect;

最后郑重提醒：别忘了在构造函数加上这句setMouseTracking(true); 切记切记！！！