11 Windows编程——定时器

周期性的发送WWL_TIMER消息的一个东西，这个周期可以由程序员自己设定。
设定周期的数是SetTimer，停止定时器消息发送的函数是：Killximer；

定时器消息的特点：

1.不准确（也就是说，你设定的周期是1秒，那么有可能在980毫秒的时候，这个WM_TIMER消息就来了，也有可能1010毫秒的时候才来）
2.可能被合并（这个和WL_PAINT消息类似）；

SetTimer

UINT_PTR WINAPI SetTimer(
  _In_opt_ HWND      hWnd,
  _In_     UINT_PTR  nIDEvent,
  _In_     UINT      uElapse,
  _In_opt_ TIMERPROC lpTimerFunc
);

hWnd：　　指向一个和定时器关联的窗口。如果想改变一个窗口原有定时器的周期，那么这个bwnd必须传递NULL。

nIDEvent： 定时器的标识；

uElapse：   定义周期（毫秒）

lpTimerFunc：指向一个函数的指针，如果这个函数指针是NULL，那么定时器周期性发送WA_TIMER消息给窗口，否则，定时器周期性的调用这个函数，不再发送WM_TIMER消息。函数原型：

TimerProc

VOID CALLBACK TimerProc(
  _In_ HWND     hwnd,
  _In_ UINT     uMsg,
  _In_ UINT_PTR idEvent,
  _In_ DWORD    dwTime
);

hwnd：　　和定时器相关联的窗口

uMsg:　　   L_TIMER

idEvent：    定时器标识

dwTime：   系统启动后，运行了多长时间（毫秒）

KillTimer

BOOL WINAPI KillTimer(
  _In_opt_ HWND     hWnd,
  _In_     UINT_PTR uIDEvent
);

hwnd：和定时器关联的窗口；

uIDEvent：定时器标识；

WM_TIMER：

wParam：定时器标识
lParam：  指向回调函数 TimerProc的指针

实现定时器源码——法一：WM_TIMER

 #include<Windows.h>
 #include<WinUser.h>
 #include<tchar.h>
 #include<stdio.h>

 #define SECOND 1000
 #define MINUTE 60000
 #define HOUR 3600000

 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);

 int WinMain(HINSTANCE hInst, HINSTANCE tmp, LPSTR szCmd, int nShow)
 {
     WNDCLASS WndClass;
     TCHAR* ClassName = TEXT("MyClass");
     HWND hwnd;
     MSG msg;

     WndClass.cbClsExtra = ;
     WndClass.cbWndExtra = ;
     WndClass.hbrBackground = (HBRUSH)(COLOR_WINDOW + );
     WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
     WndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
     WndClass.hInstance = hInst;
     WndClass.lpfnWndProc = WindProc;
     WndClass.lpszClassName = ClassName;
     WndClass.lpszMenuName = NULL;
     WndClass.style = CS_VREDRAW | CS_HREDRAW;

     RegisterClass(&WndClass);
     hwnd = CreateWindow(ClassName, TEXT("Hello"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, , , NULL, NULL, hInst, NULL);
     ShowWindow(hwnd, nShow);
     UpdateWindow(hwnd);

     while (GetMessage(&msg, NULL, , ))
     {
         TranslateMessage(&msg);
         DispatchMessage(&msg);
     }
     return ;
 }
 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 {
     HDC hdc;
     PAINTSTRUCT pt;
     static int second, minute, hour;
     static TCHAR str[] = {  };
     switch (message)
     {
     case WM_CREATE:
         SetTimer(hwnd, , SECOND, NULL);
         SetTimer(hwnd, , MINUTE, NULL);
         SetTimer(hwnd, , HOUR, NULL);
         second = ;
         minute = ;
         hour = ;
         return ;
     case WM_SIZE:
         return ;
     case WM_PAINT:
         hdc = BeginPaint(hwnd, &pt);
         Rectangle(hdc, , , , );
         _stprintf(str, TEXT("%d:%d:%d"), hour, minute, second);
         TextOut(hdc, , , str, _tcslen(str));
         EndPaint(hwnd, &pt);
         return ;
     case WM_TIMER:
         if (wParam == )
         {
             second++;
             second = second >=  ?  : second;
         }
         else if (wParam == )
         {
             minute++;
             minute = minute >=  ?  : minute;
         }
         else
             hour++;
         InvalidateRect(hwnd, NULL, TRUE);
         return ;
     case WM_DESTROY:
         KillTimer(hwnd, );
         KillTimer(hwnd, );
         KillTimer(hwnd, );
         PostQuitMessage();
         return ;
     default:
         break;
     }

     return DefWindowProc(hwnd, message, wParam, lParam);
 }

实现定时器源码——法二：TimerProc

 #include<Windows.h>
 #include<WinUser.h>
 #include<tchar.h>
 #include<stdio.h>

 #define SECOND 1000
 #define MINUTE 60000
 #define HOUR 3600000
 int second, minute, hour;

 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
 VOID CALLBACK TimerProc(HWND hWnd, UINT uMsg, UINT_PTR idEvent, DWORD dwTime);

 int WinMain(HINSTANCE hInst, HINSTANCE tmp, LPSTR szCmd, int nShow)
 {
     WNDCLASS WndClass;
     TCHAR* ClassName = TEXT("MyClass");
     HWND hwnd;
     MSG msg;

     WndClass.cbClsExtra = ;
     WndClass.cbWndExtra = ;
     WndClass.hbrBackground = (HBRUSH)(COLOR_WINDOW + );
     WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
     WndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
     WndClass.hInstance = hInst;
     WndClass.lpfnWndProc = WindProc;
     WndClass.lpszClassName = ClassName;
     WndClass.lpszMenuName = NULL;
     WndClass.style = CS_VREDRAW | CS_HREDRAW;

     RegisterClass(&WndClass);
     hwnd = CreateWindow(ClassName, TEXT("Hello"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, , , NULL, NULL, hInst, NULL);
     ShowWindow(hwnd, nShow);
     UpdateWindow(hwnd);

     while (GetMessage(&msg, NULL, , ))
     {
         TranslateMessage(&msg);
         DispatchMessage(&msg);
     }
     return ;
 }
 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 {
     HDC hdc;
     PAINTSTRUCT pt;
     static TCHAR str[] = {  };
     switch (message)
     {
     case WM_CREATE:
         SetTimer(hwnd, , SECOND, TimerProc);
         SetTimer(hwnd, , MINUTE, TimerProc);
         SetTimer(hwnd, , HOUR, TimerProc);
         second = ;
         minute = ;
         hour = ;
         return ;
     case WM_SIZE:
         return ;
     case WM_PAINT:
         hdc = BeginPaint(hwnd, &pt);
         Rectangle(hdc, , , , );
         _stprintf(str, TEXT("%d:%d:%d"),hour, minute, second);
         TextOut(hdc, , , str, _tcslen(str));
         EndPaint(hwnd, &pt);
         return ;
     case WM_DESTROY:
         KillTimer(hwnd, );
         KillTimer(hwnd, );
         KillTimer(hwnd, );
         PostQuitMessage();
         return ;
     default:
         break;
     }

     return DefWindowProc(hwnd, message, wParam, lParam);
 }

 VOID CALLBACK TimerProc(HWND hWnd, UINT uMsg, UINT_PTR idEvent, DWORD dwTime)
 {
     if (idEvent == )
     {
         second++;
         second = second >=  ?  : second;
     }
     else if (idEvent == )
     {
         minute++;
         minute = minute >=  ?  : minute;
     }
     else
         hour++;
     InvalidateRect(hWnd, NULL, TRUE);
 }