windows程序设计一个小球弹撞问题
本帖最后由 RSNrsn 于 2014-10-18 20:51 编辑代码如下：// Bounce.cpp : Defines the entry point for the application.
//
#include "stdafx.h"
#include "resource.h"
#define MAX_LOADSTRING 100
// Global Variables:
HINSTANCE hInst; // current instance
TCHAR szTitle; // The title bar text
TCHAR szWindowClass; // The title bar text
// Foward declarations of functions included in this code module:
ATOM MyRegisterClass(HINSTANCE hInstance);
BOOL InitInstance(HINSTANCE, int);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK About(HWND, UINT, WPARAM, LPARAM);
static int cxClient,cyClient,xCenter,yCenter,xTotal,yTotal,xR,yR,xMove,yMove;
int APIENTRY WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
// TODO: Place code here.
MSG msg;
HACCEL hAccelTable;
// Initialize global strings
LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
LoadString(hInstance, IDC_BOUNCE, szWindowClass, MAX_LOADSTRING);
MyRegisterClass(hInstance);
// Perform application initialization:
if (!InitInstance (hInstance, nCmdShow))
{
return FALSE;
}
hAccelTable = LoadAccelerators(hInstance, (LPCTSTR)IDC_BOUNCE);
// Main message loop:
while (GetMessage(&msg, NULL, 0, 0))
{
if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
return msg.wParam;
}
//
//FUNCTION: MyRegisterClass()
//
//PURPOSE: Registers the window class.
//
//COMMENTS:
//
// This function and its usage is only necessary if you want this code
// to be compatible with Win32 systems prior to the 'RegisterClassEx'
// function that was added to Windows 95. It is important to call this function
// so that the application will get 'well formed' small icons associated
// with it.
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
WNDCLASSEX wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = (WNDPROC)WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance, (LPCTSTR)IDI_BOUNCE);
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = (LPCSTR)IDC_BOUNCE;
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = LoadIcon(wcex.hInstance, (LPCTSTR)IDI_SMALL);
return RegisterClassEx(&wcex);
}
//
// FUNCTION: InitInstance(HANDLE, int)
//
// PURPOSE: Saves instance handle and creates main window
//
// COMMENTS:
//
// In this function, we save the instance handle in a global variable and
// create and display the main program window.
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
HWND hWnd;
hInst = hInstance; // Store instance handle in our global variable
hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);
if (!hWnd)
{
return FALSE;
}
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
return TRUE;
}
//
//FUNCTION: WndProc(HWND, unsigned, WORD, LONG)
//
//PURPOSE:Processes messages for the main window.
//
//WM_COMMAND - process the application menu
//WM_PAINT - Paint the main window
//WM_DESTROY - post a quit message and return
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
int wmId, wmEvent;
PAINTSTRUCT ps;
HDC hdc,hdcMem;
static int i=0;
static HBITMAP bitmap;
HBRUSH brush;
switch (message)
{
case WM_CREATE:
SetTimer(hWnd,1,100,NULL);
break;
case WM_SIZE:
xCenter = (cxClient = LOWORD(lParam))/2;
yCenter = (cyClient = HIWORD(lParam))/2;
xR = 20;
yR = 20;
xMove = xR/2;
yMove = yR/2;
xTotal = 2*(xR + xMove);
yTotal = 2*(yR + yMove);
hdc = GetDC(hWnd);
bitmap = CreateCompatibleBitmap(hdc,xTotal,yTotal);
hdcMem = CreateCompatibleDC(NULL);
ReleaseDC(hWnd,hdc);
SelectObject(hdcMem,bitmap);
Rectangle( hdcMem,-1,-1,xTotal+1,yTotal+1);
brush = CreateHatchBrush(HS_DIAGCROSS,0L);
SelectObject(hdcMem,brush);
SetBkColor(hdcMem, RGB(255,0,255));
Ellipse(hdcMem,xMove,yMove,xTotal-xMove,yTotal-yMove);
DeleteObject(hdcMem);
break;
case WM_COMMAND:
wmId = LOWORD(wParam);
wmEvent = HIWORD(wParam);
// Parse the menu selections:
switch (wmId)
{
case IDM_ABOUT:
DialogBox(hInst, (LPCTSTR)IDD_ABOUTBOX, hWnd, (DLGPROC)About);
break;
case IDM_EXIT:
DestroyWindow(hWnd);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
break;
case WM_TIMER:
hdc = GetDC(hWnd);
if(!bitmap)
break;
hdcMem = CreateCompatibleDC(hdc);
SelectObject(hdcMem, bitmap);
BitBlt(hdc, xCenter - xTotal / 2, yCenter - yTotal / 2, xTotal, yTotal,
hdcMem, 0,0,SRCCOPY);
xCenter += xMove;
yCenter += yMove;
if (((xCenter+xR/2) >= cxClient)||((xCenter-xR/2) <= 0))
{
xMove = -xMove;
}
if ((yCenter+yR/2 >=cyClient)||(yCenter-yR/2 <= 0))
{
yMove = -yMove;
}
//这行代码删掉就不行为啥呢？
DeleteObject(hdcMem);
ReleaseDC(hWnd,hdc);
break;
case WM_PAINT:
hdc = BeginPaint(hWnd, &ps);
// TODO: Add any drawing code here...
EndPaint(hWnd, &ps);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
// Mesage handler for about box.
LRESULT CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_INITDIALOG:
return TRUE;
case WM_COMMAND:
if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
{
EndDialog(hDlg, LOWORD(wParam));
return TRUE;
}
break;
}
return FALSE;
}
为啥注释这一行就运行不出效果。
如图C:\Users\Administrator\Desktop 把问题求助顶起来{:7_146:}
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