Question

我目前正在使用SDL2 + windows.h库在Visual C / C ++中开发GameBoy / GameBoyColor模拟器，以提供其他功能。我已经成功地将菜单项添加到了我的SDL创建的窗口中，但是在单击菜单项时尝试处理由窗口发送的消息时遇到麻烦... Image of running application with window menu items

在我的设计中，我决定创建一个单独的源文件，该文件的名称空间包含各种程序实用程序，例如窗口管理功能。因此，我创建了一个名为getMenuEvent()的函数，该函数包含窗口实例的消息循环，从技术上讲，该函数应在同一命名空间中调用我定义的WndProc()函数，以查看{{1 }}是...

这是我写的实用程序名称空间源文件

wParam

这是我的主要爱好：

HWND getSDLWinHandle(SDL_Window* win)
{
    SDL_SysWMinfo infoWindow;
    SDL_VERSION(&infoWindow.version);
    if (!SDL_GetWindowWMInfo(win, &infoWindow))
    {
        std::cout << "test";
        return NULL;
    }
    return (infoWindow.info.win.window);
}

//Initializes the native windows drop down menu elements of the window
void ActivateMenu(HWND windowRef)
{
    hMenuBar = CreateMenu();
    hFile = CreateMenu();
    hEdit = CreateMenu();
    hHelp = CreateMenu();

    AppendMenu(hMenuBar, MF_POPUP, (UINT_PTR)hFile, "File");
    AppendMenu(hMenuBar, MF_POPUP, (UINT_PTR)hEdit, "Edit");
    AppendMenu(hMenuBar, MF_POPUP, (UINT_PTR)hHelp, "Help");

    AppendMenu(hFile, MF_STRING, ID_LOADROM, "Load ROM");
    AppendMenu(hFile, MF_STRING, ID_EXIT, "Exit");

    AppendMenu(hEdit, MF_STRING, ID_CONTROLS, "Configure Controls");

    AppendMenu(hHelp, MF_STRING, ID_ABOUT, "About");

    SetMenu(windowRef, hMenuBar);
}

void getMenuEvent(MSG* message, HWND hwnd)
{
    if (GetMessage(message, hwnd, 0, 0))
    {
        TranslateMessage(message);
        DispatchMessage(message);
    }
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam)
{
    std::cout << "test" << std::endl;
    switch (message)
    {
    case WM_COMMAND:
        if (LOWORD(wparam) == ID_EXIT)
        {
            exit(0);
        }
        break;
    }
}

此刻，菜单栏会弹出并显示子菜单项（例如File-> Load ROM），但是当我单击子菜单项（如Exit）时什么也没有发生。我如何让我的程序调用在实用程序名称空间中定义的WndProc（）函数，以便处理来自菜单项单击的消息？我的方法可以吗？

P.S。我从多个在线资源中了解到DispatchMessage（）函数会自动调用WndProc（）函数，但就我而言似乎没有发生。

Answer 1

找到了一个简单的修复程序，它也大量清理了代码！

结果是，您可以使用SDL的事件处理系统来检索winAPI消息。

这是已编辑的主要功能：

const char* title = "GBemu";
bool isRunning = true;
SDL_Event mainEvent;
HWND windowHandler;

//Initialize the SDL Subsystems
if (SDL_Init(SDL_INIT_EVERYTHING) != 0)
{
    SDL_Log("Unable to initialize SDL subsystems: %s", SDL_GetError());
    return 1;
}

//Create a window pointer + allocate a window object to it.
SDL_Window* mainWindow = SDL_CreateWindow(title, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1000, 1000, NULL);
windowHandler = utilities::getSDLWinHandle(mainWindow);

//Activate the menu bar of the window
utilities::ActivateMenu(windowHandler);

//Initialize Rendering Device
SDL_Renderer* mainRenderer = SDL_CreateRenderer(mainWindow, -1, 0);
SDL_SetRenderDrawColor(mainRenderer, 0, 0, 0, 255);
SDL_RenderPresent(mainRenderer);

//Enable WinAPI Events Processing
SDL_EventState(SDL_SYSWMEVENT, SDL_ENABLE);

while (isRunning)
{
    SDL_PollEvent(&mainEvent);
    switch (mainEvent.type)
    {
    case SDL_WINDOWEVENT_CLOSE:
        mainEvent.type = SDL_QUIT;
        SDL_PushEvent(&mainEvent);
        break;
    case SDL_SYSWMEVENT:
        if (mainEvent.syswm.msg->msg.win.msg == WM_COMMAND)
        {
            if (LOWORD(mainEvent.syswm.msg->msg.win.wParam) == ID_EXIT)
            {
                isRunning = false;
            }
        }
        break;
    case SDL_QUIT:
        isRunning = false;
        break;
    };
}

return 0;

这是编辑的名称空间实用程序源文件：

//Namespace variables/Defines
#define ID_LOADROM 1
#define ID_ABOUT 2
#define ID_EXIT 3
#define ID_CONTROLS 4
static HMENU hHelp;
static HMENU hEdit;
static HMENU hFile;
static HMENU hMenuBar;


//Function which retrieves the address/Handle of an SDL window
//Also retrieves the specific subsystem used by SDL to create that window which is platform specific (Windows, MAC OS x, IOS, etc...)
HWND getSDLWinHandle(SDL_Window* win)
{
    SDL_SysWMinfo infoWindow;
    SDL_VERSION(&infoWindow.version);
    if (!SDL_GetWindowWMInfo(win, &infoWindow))
    {
        return NULL;
    }
    return (infoWindow.info.win.window);
}

//Initializes the native windows drop down menu elements of the window
void ActivateMenu(HWND windowRef)
{
    hMenuBar = CreateMenu();
    hFile = CreateMenu();
    hEdit = CreateMenu();
    hHelp = CreateMenu();

    AppendMenu(hMenuBar, MF_POPUP, (UINT_PTR)hFile, "File");
    AppendMenu(hMenuBar, MF_POPUP, (UINT_PTR)hEdit, "Edit");
    AppendMenu(hMenuBar, MF_POPUP, (UINT_PTR)hHelp, "Help");

    AppendMenu(hFile, MF_STRING, ID_LOADROM, "Load ROM");
    AppendMenu(hFile, MF_STRING, ID_EXIT, "Exit");

    AppendMenu(hEdit, MF_STRING, ID_CONTROLS, "Configure Controls");

    AppendMenu(hHelp, MF_STRING, ID_ABOUT, "About");

    SetMenu(windowRef, hMenuBar);
}

为了使SDL检索这些消息，要包括两个重要步骤：

必须在事件检查之前执行对SDL_EventState（）的调用。这是因为默认情况下，SDL在检查事件时会忽略本机API消息，以提高可移植性。
对SDL创建的窗口的句柄的引用必须在代码中的某个地方方便使用，以便向其中添加WinAPI菜单。可以通过调用SDL_GetWindowWMInfo（）函数轻松地完成此操作，该函数将返回一个具有HWND窗口句柄数据成员的SDL_SysWMInfo对象。

使用此选项，当用户单击“文件”菜单中的“退出”选项时，程序成功退出。

希望这会帮助那些打算做类似事情的人！

SDL2 + Win32 API菜单栏单击事件不起作用

1 个答案: