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 = 0;
    WndClass.cbWndExtra = 0;
    WndClass.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    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, 500, 300, NULL, NULL, hInst, NULL);
    ShowWindow(hwnd, nShow);
    UpdateWindow(hwnd);

    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return 0;
}
LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC hdc;
    PAINTSTRUCT pt;
    static int second, minute, hour;
    static TCHAR str[1024] = { 0 };
    switch (message)
    {
    case WM_CREATE:
        SetTimer(hwnd, 1, SECOND, NULL);
        SetTimer(hwnd, 2, MINUTE, NULL);
        SetTimer(hwnd, 3, HOUR, NULL);
        second = 0;
        minute = 0;
        hour = 0;
        return 0;
    case WM_SIZE:
        return 0;
    case WM_PAINT:
        hdc = BeginPaint(hwnd, &pt);
        Rectangle(hdc, 10, 10, 100, 30);
        _stprintf(str, TEXT("%d:%d:%d"), hour, minute, second);
        TextOut(hdc, 13, 11, str, _tcslen(str));
        EndPaint(hwnd, &pt);
        return 0;
    case WM_TIMER:
        if (wParam == 1)
        {
            second++;
            second = second >= 60 ? 0 : second;
        }
        else if (wParam == 2)
        {
            minute++;
            minute = minute >= 60 ? 0 : minute;
        }
        else
            hour++;
        InvalidateRect(hwnd, NULL, TRUE);
        return 0;
    case WM_DESTROY:
        KillTimer(hwnd, 1);
        KillTimer(hwnd, 2);
        KillTimer(hwnd, 3);
        PostQuitMessage(0);
        return 0;
    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 = 0;
    WndClass.cbWndExtra = 0;
    WndClass.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    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, 500, 300, NULL, NULL, hInst, NULL);
    ShowWindow(hwnd, nShow);
    UpdateWindow(hwnd);

    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return 0;
}
LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC hdc;
    PAINTSTRUCT pt;
    static TCHAR str[1024] = { 0 };
    switch (message)
    {
    case WM_CREATE:
        SetTimer(hwnd, 1, SECOND, TimerProc);
        SetTimer(hwnd, 2, MINUTE, TimerProc);
        SetTimer(hwnd, 3, HOUR, TimerProc);
        second = 0;
        minute = 0;
        hour = 0;
        return 0;
    case WM_SIZE:
        return 0;
    case WM_PAINT:
        hdc = BeginPaint(hwnd, &pt);
        Rectangle(hdc, 10, 10, 100, 30);
        _stprintf(str, TEXT("%d:%d:%d"),hour, minute, second);
        TextOut(hdc, 13, 11, str, _tcslen(str));
        EndPaint(hwnd, &pt);
        return 0;
    case WM_DESTROY:
        KillTimer(hwnd, 1);
        KillTimer(hwnd, 2);
        KillTimer(hwnd, 3);
        PostQuitMessage(0);
        return 0;
    default:
        break;
    }

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

VOID CALLBACK TimerProc(HWND hWnd, UINT uMsg, UINT_PTR idEvent, DWORD dwTime)
{
    if (idEvent == 1)
    {
        second++;
        second = second >= 60 ? 0 : second;
    }
    else if (idEvent == 2)
    {
        minute++;
        minute = minute >= 60 ? 0 : minute;
    }
    else
        hour++;
    InvalidateRect(hWnd, NULL, TRUE);
}