C语言全局时钟(Windows程序设计 第五版 )

#include <Windows.h>

#define ID_TIMER 1

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR szCmdLine, int iCmdShow)
{
TCHAR szAppName[20] = TEXT("Beeper1");
HWND hwnd;
MSG msg;
WNDCLASS CLS;

CLS.style			= CS_HREDRAW | CS_VREDRAW;
CLS.lpfnWndProc		= WndProc;
CLS.cbClsExtra		= 0;
CLS.cbWndExtra		= 0;
CLS.hInstance		= hInstance;
CLS.hIcon			= LoadIcon(NULL, IDI_APPLICATION);
CLS.hCursor			= LoadCursor(NULL, IDC_ARROW);
CLS.hbrBackground   = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
CLS.lpszMenuName	= NULL;
CLS.lpszClassName	= szAppName;

if (!RegisterClass(&CLS))
{
MessageBox(NULL, TEXT("时钟测试"), TEXT("提示"), MB_ICONERROR);
return 0;
}

hwnd = CreateWindow(
szAppName,
TEXT("时钟测试"),
WS_OVERLAPPEDWINDOW,
0,//CW_USEDEFAULT,
0,//CW_USEDEFAULT,
200,//CW_USEDEFAULT,
150,//CW_USEDEFAULT,
NULL,
NULL,
hInstance,
NULL
);

ShowWindow(hwnd, iCmdShow);
UpdateWindow(hwnd);

while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}

return msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
static BOOL fFlipFlop = FALSE;
HBRUSH hBrush;
HDC hdc;
PAINTSTRUCT ps;
RECT rc;
int ScreenX, ScreenY;

switch (message)
{
case WM_CREATE:
//启动时钟ID_TIMER
SetTimer(hwnd, ID_TIMER, 1000, NULL);
//获取窗口的RECT
GetClientRect(hwnd, &rc);
//获取屏幕的宽度
ScreenX = GetSystemMetrics(SM_CXSCREEN);
//获取屏幕的高度
ScreenY = GetSystemMetrics(SM_CYSCREEN);
//将窗口居中显示
MoveWindow(hwnd, (ScreenX - (rc.right - rc.left)) / 2, (ScreenY - (rc.bottom - rc.top)) / 2, (rc.right - rc.left), rc.bottom - rc.top, FALSE);
//SetWindowPos(hwnd, NULL, (GetSystemMetrics(SM_CXSCREEN) - (rc.right - rc.left)) / 2, (GetSystemMetrics(SM_CYSCREEN) - (rc.bottom - rc.top)) / 2, (rc.right - rc.left), rc.bottom - rc.top, NULL);
return 0;
case WM_TIMER:
//发声
MessageBeep(MB_ICONINFORMATION);
fFlipFlop = !fFlipFlop;
//使整个客户区失效
InvalidateRect(hwnd, NULL, FALSE);
return 0;
case WM_PAINT:
//获取失效区域，以开始绘制失效区域
hdc = BeginPaint(hwnd, &ps);
//获取窗口的RECT
GetClientRect(hwnd, &rc);
//创建画刷
hBrush = CreateSolidBrush(fFlipFlop ? RGB(255,0,0) : RGB(0,0,255));
//用指定画刷填充矩形区域
FillRect(hdc, &rc, hBrush);
//结束绘制
EndPaint(hwnd, &ps);
//释放画刷
DeleteObject(hBrush);
return 0;
case WM_DESTROY:
//终止时钟ID_TIMER
KillTimer(hwnd, ID_TIMER);
//关闭窗口
PostQuitMessage(0);
return 0;
}
//--其他消息使用默认处理方式
return DefWindowProc(hwnd, message, wParam, lParam);
}