[WINAPI] Code điều chỉnh button bằng 4 nút di chuyển

chúng ta tạo 1 button và điều chỉnh button đó bằng 4 nút.

source code như sau:

#if defined(UNICODE) && !defined(_UNICODE)

    #define _UNICODE

#elif defined(_UNICODE) && !defined(UNICODE)

    #define UNICODE

#endif

#include <tchar.h>

#include <windows.h>

/*  Declare Windows procedure  */

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

HWND textfield, button;

int x=100,y=100;

void reset_key()

{

    if(x<0)

    {

        x=0;

    }

     if(y<0)

    {

        y=0;

    }

     if(x>450)

    {

        x=450;

    }

     if(y>470)

    {

        y=470;

    }

}

/*  Make the class name into a global variable  */

TCHAR szClassName[ ] = _T("CodeBlocksWindowsApp");

int WINAPI WinMain (HINSTANCE hThisInstance,

                     HINSTANCE hPrevInstance,

                     LPSTR lpszArgument,

                     int nCmdShow)

{

    HWND hwnd;               /* This is the handle for our window */

    MSG messages;            /* Here messages to the application are saved */

    WNDCLASSEX wincl;        /* Data structure for the windowclass */

    /* The Window structure */

    wincl.hInstance = hThisInstance;

    wincl.lpszClassName = szClassName;

    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */

    wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */

    wincl.cbSize = sizeof (WNDCLASSEX);

    /* Use default icon and mouse-pointer */

    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);

    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);

    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);

    wincl.lpszMenuName = NULL;                 /* No menu */

    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */

    wincl.cbWndExtra = 0;                      /* structure or the window instance */

    /* Use Windows's default colour as the background of the window */

    wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

    /* Register the window class, and if it fails quit the program */

    if (!RegisterClassEx (&wincl))

        return 0;

    /* The class is registered, let's create the program*/

    hwnd = CreateWindowEx (

           0,                   /* Extended possibilites for variation */

           szClassName,         /* Classname */

           _T("Quynh - application 1"),       /* Title Text */

           WS_MINIMIZEBOX|WS_SYSMENU, /* not change window */

           CW_USEDEFAULT,       /* Windows decides the position */

           CW_USEDEFAULT,       /* where the window ends up on the screen */

           500,                 /* The programs width */

           500,                 /* and height in pixels */

           HWND_DESKTOP,        /* The window is a child-window to desktop */

           NULL,                /* No menu */

           hThisInstance,       /* Program Instance handler */

           NULL                 /* No Window Creation data */

           );

    /* Make the window visible on the screen */

    ShowWindow (hwnd, nCmdShow);

    /* Run the message loop. It will run until GetMessage() returns 0 */

    while (GetMessage (&messages, NULL, 0, 0))

    {

        /* Translate virtual-key messages into character messages */

        TranslateMessage(&messages);

        /* Send message to WindowProcedure */

        DispatchMessage(&messages);

    }

    /* The program return-value is 0 - The value that PostQuitMessage() gave */

    return messages.wParam;

}

/*  This function is called by the Windows function DispatchMessage()  */

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

{

    switch (message)                  /* handle the messages */

    {

        case WM_CREATE:

        button = CreateWindow("BUTTON","0",

                              WS_VISIBLE|WS_CHILD|WS_BORDER,

                              y,x,25,25,

                              hwnd,NULL,NULL,NULL);

        break;

        case WM_DESTROY:

            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */

            break;

        case WM_KEYDOWN:

            //Hide button

           // EnableWindow( button,  false);

           ShowWindow(button,SW_HIDE);

            //Press key up key: moview button

            if (GetAsyncKeyState(VK_UP)){

               x = x-25;

                reset_key();

            ShowWindow(button,SW_HIDE);

            button =CreateWindow("BUTTON","0",

                              WS_VISIBLE|WS_CHILD|WS_BORDER,

                              y,x,25,25,

                              hwnd,NULL,NULL,NULL);

            }

                //Press Key down

              if (GetAsyncKeyState(VK_DOWN)){

               x = x+25;

               reset_key(); ShowWindow(button,SW_HIDE);

            button =CreateWindow("BUTTON","0",

                              WS_VISIBLE|WS_CHILD|WS_BORDER,

                              y,x,25,25,

                              hwnd,NULL,NULL,NULL);

            }

            //Key left

             if (GetAsyncKeyState(VK_LEFT)){

               y= y-25;

               reset_key(); ShowWindow(button,SW_HIDE);

            button =CreateWindow("BUTTON","0",

                              WS_VISIBLE|WS_CHILD|WS_BORDER,

                              y,x,25,25,

                              hwnd,NULL,NULL,NULL);

            }

            //Key right

            if (GetAsyncKeyState(VK_RIGHT)){

               y= y+25;

               reset_key(); ShowWindow(button,SW_HIDE);

            button =CreateWindow("BUTTON","0",

                              WS_VISIBLE|WS_CHILD|WS_BORDER,

                              y,x,25,25,

                              hwnd,NULL,NULL,NULL);

            }

        break;

        default:                      /* for messages that we don't deal with */

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

    }

    return 0;

}