Qt实现可拉伸和可移动无边框的Widget

最新推荐文章于 2024-08-09 11:44:08 发布

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原文链接：https://www.cnblogs.com/umichan0621/p/16454668.html

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本文介绍如何在Qt中创建可自定义移动与拉伸行为的无边框窗口。通过设置特定的边界与高度，用户可以控制窗口的哪些部分可用于拖动与拉伸。此方法适用于希望在不使用标准窗口装饰的情况下提供交互性的应用程序。

使用FramelessWindowHint设置之后Widget不能移动和拉伸，需要自己实现

setWindowFlags(Qt::FramelessWindowHint);

.h文件

#pragma once
#include <QWidget>

class FramelessWidget : public QWidget {
  Q_OBJECT
 public:
  FramelessWidget(QWidget* Parent = Q_NULLPTR);
  void set_boundary(int32_t Boundary, int32_t MoveHeight);

 protected:
  bool nativeEvent(const QByteArray& EventType, void* pMessage,
                   long* pResult) override;

 private:
  int32_t m_Boundary;    //调整拉伸生效的范围
  int32_t m_MoveHeight;  //调整拖动生效的范围
};

.cpp文件

默认4边4角都可拉伸，整个窗体不可移动，要减少拉伸边数直接注释即可

#include <windows.h>
#include <windowsx.h>

#include "ui_frameless_widget.h"

FramelessWidget::FramelessWidget(QWidget* parent)
    : QWidget(parent),
      m_Boundary(0),
      m_MoveHeight(0)  //默认无法拖动和拉伸
{
  // setAttribute(Qt::WA_TranslucentBackground, true);
  setWindowFlags(Qt::Window | Qt::FramelessWindowHint);  //设置为无边框窗口
}

void FramelessWidget::set_boundary(int32_t Boundary, int32_t MoveHeight) {
  m_Boundary = Boundary;
  m_MoveHeight = MoveHeight;
}

bool FramelessWidget::nativeEvent(const QByteArray& EventType, void* pMessage,
                                  long* pResult) {
  MSG* pMsg = (MSG*)pMessage;
  switch (pMsg->message) {
    case WM_NCHITTEST:
      int PosX = GET_X_LPARAM(pMsg->lParam) - this->frameGeometry().x();
      int PosY = GET_Y_LPARAM(pMsg->lParam) - this->frameGeometry().y();
      if (childAt(PosX, PosY) == 0) {
        //拖拽生效区域
        if (PosY <= m_MoveHeight) {
          *pResult = HTCAPTION;
        }
      } else {
        return false;
      }
      if (PosX < m_Boundary && PosY > (height() - m_Boundary) &&
          PosY < height())
        *pResult = HTBOTTOMLEFT;  //左下
      else if (PosX > (width() - m_Boundary) && PosX < width() &&
               PosY > (height() - m_Boundary) && PosY < height())
        *pResult = HTBOTTOMRIGHT;  //右下
      else if (PosX < m_Boundary && PosY < m_Boundary)
        *pResult = HTTOPLEFT;  //左上
      else if (PosX > (width() - m_Boundary) && PosX < width() &&
               PosY < m_Boundary)
        *pResult = HTTOPRIGHT;  //右上
      else if (PosX < m_Boundary)
        *pResult = HTLEFT;  //左
      else if (PosX > (width() - m_Boundary) && PosX < width())
        *pResult = HTRIGHT;  //右
      else if (PosY < m_Boundary)
        *pResult = HTTOP;  //上
      else if (PosY > (height() - m_Boundary) && PosY < height())
        *pResult = HTBOTTOM;  //下
      return true;
  }
  return false;
}