这个范例是用Windows API实现的，因为根据我的测试，用纯Qt实现会有一些缺点。无边框窗口是普通窗口通过响应WM_NCCALCSIZE消息将边框去掉的窗口，并不是Qt中把窗口设置一个FramelessWindowHint属性然后添加窗口内容。这二者的效果和对系统操作（比如把窗口拖到屏幕最上方然后松开自动最大化窗口）的支持差别很大。我的代码是根据GitHub上的开源项目BorderlessWindow写的。它是基于Windows API写的，而我这个例子是基于Qt+Windows API写的，实现代码并不相同。BorderlessWindow原始项目可以参考以下链接：
- 知乎问答链接：https://www.zhihu.com/question/346558582
- GitHub上的源代码：GitHub - melak47/BorderlessWindow: basic win32 example of a borderless window (with aero shadows)
下面是普通显示和最大化显示的窗口效果图。我在窗口中加了很少的内容，如果你要是用可以很方便地修改它：
上代码，头文件（需要#include "qt_windows.h"）：
class MDiyWindow : public QWidget
{
Q_OBJECT
public:
MDiyWindow(QWidget *parent = nullptr);
~MDiyWindow();
private:
bool nativeEvent(const QByteArray &eventType, void *message, long *result) override;
long hitTest(HWND hWnd, POINT cursor) const;
bool isCompositionEnabled();
void adjustRectIfMaximized(HWND window, RECT& rect);
bool isMaximized(HWND hwnd);
private slots:
void on_pbClose_clicked();
void groupButtonClicked(int id);
private:
Ui::MDiyWindowClass ui;
};
CPP文件：
#include "windowsx.h"
#include "dwmapi.h"
#pragma comment(lib, "dwmapi.lib")
MDiyWindow::MDiyWindow(QWidget *parent)
: QWidget(parent)
{
ui.setupUi(this);
setWindowFlag(Qt::Window);
setWindowTitle(u8"无边框窗口测试");
setGeometry(400, 400, 800, 500);
HWND hWnd = (HWND)winId();
SetWindowPos(hWnd, 0, 0, 0, 0, 0, SWP_FRAMECHANGED | SWP_NOSIZE | SWP_NOMOVE);
QButtonGroup* group = new QButtonGroup(this);
group->addButton(ui.pbPage1, 0);
group->addButton(ui.pbPage2, 1);
group->addButton(ui.pbPage3, 2);
connect(group, QOverload<int>::of(&QButtonGroup::buttonClicked), this, &MDiyWindow::groupButtonClicked);
ui.hlMainTool->setAlignment(ui.pbClose, Qt::AlignTop);
ui.pbPage1->setChecked(true);
}
MDiyWindow::~MDiyWindow()
{
}
void MDiyWindow::groupButtonClicked(int id)
{
ui.swPanels->setCurrentIndex(id);
}
void MDiyWindow::on_pbClose_clicked()
{
close();
}
bool MDiyWindow::nativeEvent(const QByteArray &eventType, void *message, long* result)
{
MSG* msg = (MSG*)message;
switch (msg->message)
{
case WM_NCCALCSIZE:
if (msg->wParam == TRUE)
{
NCCALCSIZE_PARAMS* params = reinterpret_cast<NCCALCSIZE_PARAMS*>(msg->lParam);
adjustRectIfMaximized(msg->hwnd, params->rgrc[0]);
*result = 0;
return true;
}
break;
case WM_NCHITTEST:
*result = hitTest(msg->hwnd, { GET_X_LPARAM(msg->lParam), GET_Y_LPARAM(msg->lParam) });
return true;
case WM_NCACTIVATE:
if (!isCompositionEnabled())
{
*result = TRUE; /* 防止显示Windows基本主题的边框 */
return true;
}
break;
default:
break;
}
return false;
}
bool MDiyWindow::isCompositionEnabled()
{
BOOL composition_enabled = FALSE;
if (DwmIsCompositionEnabled(&composition_enabled) == S_OK)
{
return composition_enabled;
}
return false;
}
bool MDiyWindow::isMaximized(HWND hwnd)
{
WINDOWPLACEMENT placement;
if (GetWindowPlacement(hwnd, &placement))
{
return placement.showCmd == SW_MAXIMIZE;
}
return false;
}
void MDiyWindow::adjustRectIfMaximized(HWND window, RECT& rect)
{
if (!isMaximized(window))
{
return;
}
auto monitor = MonitorFromWindow(window, MONITOR_DEFAULTTONULL);
if (!monitor)
{
return;
}
MONITORINFO monitor_info = { 0 };
monitor_info.cbSize = sizeof(monitor_info);
if (GetMonitorInfo(monitor, &monitor_info))
{
rect.left = monitor_info.rcWork.left - 6;
rect.top = monitor_info.rcWork.top - 6;
rect.right = monitor_info.rcWork.right + 6;
rect.bottom = monitor_info.rcWork.bottom + 6;
}
}
long MDiyWindow::hitTest(HWND hWnd, POINT cursor) const
{
const POINT border
{
GetSystemMetrics(SM_CXFRAME) + GetSystemMetrics(SM_CXPADDEDBORDER),
GetSystemMetrics(SM_CYFRAME) + GetSystemMetrics(SM_CXPADDEDBORDER)
};
RECT window;
if (!GetWindowRect(hWnd, &window))
{
return HTNOWHERE;
}
QWidget* child = childAt(mapFromGlobal({ cursor.x, cursor.y }));
if (child)
{
return HTCLIENT;
}
enum RegionMask {
CLIENT = 0b0000,
LEFT = 0b0001,
RIGHT = 0b0010,
TOP = 0b0100,
BOTTOM = 0b1000,
};
const auto result =
LEFT * (cursor.x < (window.left + border.x)) |
RIGHT * (cursor.x >= (window.right - border.x)) |
TOP * (cursor.y < (window.top + border.y)) |
BOTTOM * (cursor.y >= (window.bottom - border.y));
switch (result)
{
case LEFT:
return HTLEFT;
case RIGHT:
return HTRIGHT;
case TOP:
return HTTOP;
case BOTTOM:
return HTBOTTOM;
case TOP | LEFT:
return HTTOPLEFT;
case TOP | RIGHT:
return HTTOPRIGHT;
case BOTTOM | LEFT:
return HTBOTTOMLEFT;
case BOTTOM | RIGHT:
return HTBOTTOMRIGHT;
case CLIENT:
return HTCAPTION;
default: // 其它
break;
}
return HTNOWHERE;
}
UI文件：
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>MDiyWindowClass</class>
<widget class="QWidget" name="MDiyWindowClass">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>600</width>
<height>400</height>
</rect>
</property>
<property name="windowTitle">
<string>MDiyWindow</string>
</property>
<property name="styleSheet">
<string notr="true">#MDiyWindowClass
{
background-color: rgb(220, 220, 255);
}
#pbPage1, #pbPage2, #pbPage3
{
background-color: rgb(223, 223, 223);
border-bottom: 3px solid #dfdfdf;
border-top: none;
border-left: none;
border-right: none;
}
#pbPage1:checked, #pbPage2:checked, #pbPage3:checked
{
background-color: rgb(233, 233, 233);
border-bottom: 3px solid #ff5f00;
border-top: none;
border-left: none;
border-right: none;
}
#swPanels
{
background-color: rgb(240, 240, 240);
}
</string>
</property>
<layout class="QGridLayout" name="gridLayout">
<property name="leftMargin">
<number>6</number>
</property>
<property name="topMargin">
<number>6</number>
</property>
<property name="rightMargin">
<number>6</number>
</property>
<property name="bottomMargin">
<number>6</number>
</property>
<property name="verticalSpacing">
<number>0</number>
</property>
<item row="0" column="0">
<layout class="QHBoxLayout" name="hlMainTool">
<property name="spacing">
<number>0</number>
</property>
<item>
<widget class="QPushButton" name="pbPage1">
<property name="minimumSize">
<size>
<width>64</width>
<height>26</height>
</size>
</property>
<property name="text">
<string>第1页</string>
</property>
<property name="checkable">
<bool>true</bool>
</property>
</widget>
</item>
<item>
<widget class="QPushButton" name="pbPage2">
<property name="minimumSize">
<size>
<width>64</width>
<height>26</height>
</size>
</property>
<property name="text">
<string>第2页</string>
</property>
<property name="checkable">
<bool>true</bool>
</property>
</widget>
</item>
<item>
<widget class="QPushButton" name="pbPage3">
<property name="minimumSize">
<size>
<width>64</width>
<height>26</height>
</size>
</property>
<property name="text">
<string>第3页</string>
</property>
<property name="checkable">
<bool>true</bool>
</property>
</widget>
</item>
<item>
<spacer name="horizontalSpacer">
<property name="orientation">
<enum>Qt::Horizontal</enum>
</property>
<property name="sizeHint" stdset="0">
<size>
<width>40</width>
<height>20</height>
</size>
</property>
</spacer>
</item>
<item>
<widget class="QPushButton" name="pbClose">
<property name="sizePolicy">
<sizepolicy hsizetype="Fixed" vsizetype="Fixed">
<horstretch>0</horstretch>
<verstretch>0</verstretch>
</sizepolicy>
</property>
<property name="minimumSize">
<size>
<width>22</width>
<height>22</height>
</size>
</property>
<property name="maximumSize">
<size>
<width>22</width>
<height>22</height>
</size>
</property>
<property name="text">
<string>X</string>
</property>
</widget>
</item>
</layout>
</item>
<item row="1" column="0">
<widget class="QStackedWidget" name="swPanels">
<property name="frameShape">
<enum>QFrame::StyledPanel</enum>
</property>
<widget class="QWidget" name="page">
<widget class="QLabel" name="label_3">
<property name="geometry">
<rect>
<x>10</x>
<y>10</y>
<width>81</width>
<height>21</height>
</rect>
</property>
<property name="text">
<string>第1页</string>
</property>
</widget>
</widget>
<widget class="QWidget" name="page_2">
<widget class="QLabel" name="label_2">
<property name="geometry">
<rect>
<x>10</x>
<y>10</y>
<width>81</width>
<height>21</height>
</rect>
</property>
<property name="text">
<string>第2页</string>
</property>
</widget>
</widget>
<widget class="QWidget" name="page_3">
<widget class="QLabel" name="label">
<property name="geometry">
<rect>
<x>10</x>
<y>10</y>
<width>81</width>
<height>21</height>
</rect>
</property>
<property name="text">
<string>第3页</string>
</property>
</widget>
</widget>
</widget>
</item>
</layout>
</widget>
<layoutdefault spacing="6" margin="11"/>
<resources/>
<connections/>
</ui>
标签：case,return,Qt,边框,window,窗口,MDiyWindow,border,monitor From： https://www.cnblogs.com/mengxiangdu/p/16976079.html