Qt 实现无边框窗口，支持缩放窗口大小

#include "mainwindow.h" #include "ui_mainwindow.h" #include <QDesktopWidget> MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui->setupUi(this); setWindowFlags(Qt::FramelessWindowHint); mLocation = this->geometry(); mIsMax = false; mDrag = false; mZoom = false; ui->widgetTitle->installEventFilter(this); ui->btnMin->setIcon(QIcon(":/image/min.png")); ui->btnMax->setIcon(QIcon(":/image/max1.png")); ui->btnExit->setIcon(QIcon(":/image/exit.png")); //给缩放的图片label处理鼠标的按下、移动、弹起消息，进行缩放窗口功能 ui->labelZoom->installEventFilter(this); ui->labelZoom->setCursor(Qt::SizeFDiagCursor); setStyleSheet("QMainWindow{color:#E8E8E8;background:#43CD80;}"); //另外在设计器内查看widgetTitle样式，内有标题栏各个子控件的样式设置 } MainWindow::~MainWindow() { delete ui; } bool MainWindow::eventFilter(QObject *obj, QEvent *e) { if (obj == ui->widgetTitle) { if(e->type() == QEvent::MouseButtonDblClick) { on_btnMax_clicked(); return true; } } else if (obj == ui->labelZoom) { //实现拖动右下角缩放窗口 if(e->type() == QEvent::MouseButtonPress) { QMouseEvent *event = (QMouseEvent *)e; if (event->buttons() & Qt::LeftButton) { if(mIsMax) { //已最大化，就不让再拖动 return true; } mZoom = true; mZoomLocation = geometry(); mZoomPos = event->globalPos(); return true; } } else if(e->type() == QEvent::MouseMove) { QMouseEvent *event = (QMouseEvent *)e; if (mZoom && (event->buttons() & Qt::LeftButton)) { int dx = event->globalPos().x() - mZoomPos.x(); int dy = event->globalPos().y() - mZoomPos.y(); QRect rc = mZoomLocation; rc.setRight(rc.right() + dx); rc.setBottom(rc.bottom() + dy); setGeometry(rc); update(); return true; } } else if(e->type() == QEvent::MouseButtonRelease) { mZoom = false; return true; } } return QObject::eventFilter(obj, e); } void MainWindow::mousePressEvent(QMouseEvent *e)//鼠标按下事件 { if (e->button() == Qt::LeftButton) { mDrag = true; mDragPos = e->globalPos() - pos(); e->accept(); } } void MainWindow::mouseMoveEvent(QMouseEvent *e)//鼠标移动事件 { if (mDrag && (e->buttons() && Qt::LeftButton)) { move(e->globalPos() - mDragPos); e->accept(); } } void MainWindow::mouseReleaseEvent(QMouseEvent *e)//鼠标释放事件 { mDrag = false; } void MainWindow::on_btnMin_clicked() { showMinimized(); } void MainWindow::on_btnMax_clicked() { if (mIsMax) { setGeometry(mLocation); ui->btnMax->setIcon(QIcon(":/image/max1.png")); ui->btnMax->setToolTip(QStringLiteral("最大化")); } else { mLocation = geometry(); setGeometry(qApp->desktop()->availableGeometry()); ui->btnMax->setIcon(QIcon(":/image/max2.png")); ui->btnMax->setToolTip(QStringLiteral("还原")); } mIsMax = !mIsMax; } void MainWindow::on_btnExit_clicked() { qApp->exit(); }