windows API编写的应用程序，一个闹钟，运行时显示的时间与系统时间一致。

#include <afxwin.h> #include <math.h> #include "Clock.h" #include "Resource.h" #define SQUARESIZE 20 #define ID_TIMER_CLOCK 1 CMyApp myApp; ///////////////////////////////////////////////////////////////////////// // CMyApp member functions BOOL CMyApp::InitInstance () { SetRegistryKey (_T ("Programming Windows with MFC")); m_pMainWnd = new CMainWindow; if (!((CMainWindow*) m_pMainWnd)->RestoreWindowState ()) m_pMainWnd->ShowWindow (m_nCmdShow); m_pMainWnd->UpdateWindow (); return TRUE; } ///////////////////////////////////////////////////////////////////////// // CMainWindow message map and member functions BEGIN_MESSAGE_MAP (CMainWindow, CFrameWnd) ON_WM_CREATE () ON_WM_PAINT () ON_WM_TIMER () ON_WM_GETMINMAXINFO () ON_WM_NCHITTEST () ON_WM_SYSCOMMAND () ON_WM_CONTEXTMENU () ON_WM_ENDSESSION () ON_WM_CLOSE () END_MESSAGE_MAP () CMainWindow::CMainWindow () { m_bAutoMenuEnable = FALSE; CTime time = CTime::GetCurrentTime (); m_nPrevSecond = time.GetSecond (); m_nPrevMinute = time.GetMinute (); m_nPrevHour = time.GetHour () % 12; CString strWndClass = AfxRegisterWndClass ( CS_HREDRAW | CS_VREDRAW, myApp.LoadStandardCursor (IDC_ARROW), (HBRUSH) (COLOR_3DFACE + 1), myApp.LoadIcon (IDI_APPICON) ); Create (strWndClass, _T ("Clock")); } BOOL CMainWindow::PreCreateWindow (CREATESTRUCT& cs) { if (!CFrameWnd::PreCreateWindow (cs)) return FALSE; cs.dwExStyle &= ~WS_EX_CLIENTEDGE; return TRUE; } int CMainWindow::OnCreate (LPCREATESTRUCT lpcs) { if (CFrameWnd::OnCreate (lpcs) == -1) return -1; // // Set a timer to fire at 1-second intervals. // if (!SetTimer (ID_TIMER_CLOCK, 1000, NULL)) { MessageBox (_T ("SetTimer failed"), _T ("Error"), MB_ICONSTOP | MB_OK); return -1; } // // Customize the system menu. // CMenu* pMenu = GetSystemMenu (FALSE); pMenu->AppendMenu (MF_SEPARATOR); pMenu->AppendMenu (MF_STRING, IDM_SYSMENU_FULL_WINDOW, _T ("Remove &Title")); pMenu->AppendMenu (MF_STRING, IDM_SYSMENU_STAY_ON_TOP, _T ("Stay on To&p")); return 0; } void CMainWindow::OnClose () { SaveWindowState (); KillTimer (ID_TIMER_CLOCK); CFrameWnd::OnClose (); } void CMainWindow::OnEndSession (BOOL bEnding) { if (bEnding) SaveWindowState (); CFrameWnd::OnEndSession (bEnding); } void CMainWindow::OnGetMinMaxInfo (MINMAXINFO* pMMI) { pMMI->ptMinTrackSize.x = 120; pMMI->ptMinTrackSize.y = 120; } UINT CMainWindow::OnNcHitTest (CPoint point) { UINT nHitTest = CFrameWnd::OnNcHitTest (point); if ((nHitTest == HTCLIENT) && (::GetAsyncKeyState (MK_LBUTTON) < 0)) nHitTest = HTCAPTION; return nHitTest; } void CMainWindow::OnSysCommand (UINT nID, LPARAM lParam) { UINT nMaskedID = nID & 0xFFF0; if (nMaskedID == IDM_SYSMENU_FULL_WINDOW) { m_bFullWindow = m_bFullWindow ? 0 : 1; SetTitleBarState (); return; } else if (nMaskedID == IDM_SYSMENU_STAY_ON_TOP) { m_bStayOnTop = m_bStayOnTop ? 0 : 1; SetTopMostState (); return; } CFrameWnd::OnSysCommand (nID, lParam); } void CMainWindow::OnContextMenu (CWnd* pWnd, CPoint point) { CRect rect; GetClientRect (&rect); ClientToScreen (&rect); if (rect.PtInRect (point)) { CMenu* pMenu = GetSystemMenu (FALSE); UpdateSystemMenu (pMenu); int nID = (int) pMenu->TrackPopupMenu (TPM_LEFTALIGN | TPM_LEFTBUTTON | TPM_RIGHTBUTTON | TPM_RETURNCMD, point.x, point.y, this); if (nID > 0) SendMessage (WM_SYSCOMMAND, nID, 0); return; } CFrameWnd::OnContextMenu (pWnd, point); } void CMainWindow::OnTimer (UINT nTimerID) { // // Do nothing if the window is minimized. // if (IsIconic ()) return; // // Get the current time and do nothing if it hasn't changed. // CTime time = CTime::GetCurrentTime (); int nSecond = time.GetSecond (); int nMinute = time.GetMinute (); int nHour = time.GetHour () % 12; if ((nSecond == m_nPrevSecond) && (nMinute == m_nPrevMinute) && (nHour == m_nPrevHour)) return; // // Center the origin and switch to the MM_ISOTROPIC mapping mode. // CRect rect; GetClientRect (&rect); CClientDC dc (this); dc.SetMapMode (MM_ISOTROPIC); dc.SetWindowExt (1000, 1000); dc.SetViewportExt (rect.Width (), -rect.Height ()); dc.SetViewportOrg (rect.Width () / 2, rect.Height () / 2); // // If minutes have changed, erase the hour and minute hands. // COLORREF clrColor = ::GetSysColor (COLOR_3DFACE); if (nMinute != m_nPrevMinute) { DrawHand (&dc, 200, 4, (m_nPrevHour * 30) + (m_nPrevMinute / 2), clrColor); DrawHand (&dc, 400, 8, m_nPrevMinute * 6, clrColor); m_nPrevMinute = nMinute; m_nPrevHour = nHour; } // // If seconds have changed, erase the second hand and redraw all hands. // if (nSecond != m_nPrevSecond) { DrawSecondHand (&dc, 400, 8, m_nPrevSecond * 6, clrColor); DrawSecondHand (&dc, 400, 8, nSecond * 6, RGB (0, 0, 0)); DrawHand (&dc, 200, 4, (nHour * 30) + (nMinute / 2), RGB (0, 0, 0)); DrawHand (&dc, 400, 8, nMinute * 6, RGB (0, 0, 0)); m_nPrevSecond = nSecond; } } void CMainWindow::OnPaint () { CRect rect; GetClientRect (&rect); CPaintDC dc (this); dc.SetMapMode (MM_ISOTROPIC); dc.SetWindowExt (1000, 1000); dc.SetViewportExt (rect.Width (), -rect.Height ()); dc.SetViewportOrg (rect.Width () / 2, rect.Height () / 2); DrawClockFace (&dc); DrawHand (&dc, 200, 4, (m_nPrevHour * 30) + (m_nPrevMinute / 2), RGB (0, 0, 0)); DrawHand (&dc, 400, 8, m_nPrevMinute * 6, RGB (0, 0, 0)); DrawSecondHand (&dc, 400, 8, m_nPrevSecond * 6, RGB (0, 0, 0)); } void CMainWindow::DrawClockFace (CDC* pDC) { static CPoint point[12] = { CPoint ( 0, 450), // 12 o'clock CPoint ( 225, 390), // 1 o'clock CPoint ( 390, 225), // 2 o'clock CPoint ( 450, 0), // 3 o'clock CPoint ( 390, -225), // 4 o'clock CPoint ( 225, -390), // 5 o'clock CPoint ( 0, -450), // 6 o'clock CPoint (-225, -390), // 7 o'clock CPoint (-390, -225), // 8 o'clock CPoint (-450, 0), // 9 o'clock CPoint (-390, 225), // 10 o'clock CPoint (-225, 390), // 11 o'clock }; pDC->SelectStockObject (NULL_BRUSH); for (int i=0; i<12; i++) pDC->Rectangle (point[i].x - SQUARESIZE, point[i].y + SQUARESIZE, point[i].x + SQUARESIZE, point[i].y - SQUARESIZE); } void CMainWindow::DrawHand (CDC* pDC, int nLength, int nScale, int nDegrees, COLORREF clrColor) { CPoint point[4]; double nRadians = (double) nDegrees * 0.017453292; point[0].x = (int) (nLength * sin (nRadians)); point[0].y = (int) (nLength * cos (nRadians)); point[2].x = -point[0].x / nScale; point[2].y = -point[0].y / nScale; point[1].x = -point[2].y; point[1].y = point[2].x; point[3].x = -point[1].x; point[3].y = -point[1].y; CPen pen (PS_SOLID, 0, clrColor); CPen* pOldPen = pDC->SelectObject (&pen); pDC->MoveTo (point[0]); pDC->LineTo (point[1]); pDC->LineTo (point[2]); pDC->LineTo (point[3]); pDC->LineTo (point[0]); pDC->SelectObject (pOldPen); } void CMainWindow::DrawSecondHand (CDC* pDC, int nLength, int nScale, int nDegrees, COLORREF clrColor) { CPoint p