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Win32 SDK基础(四)之如何从零开始创建windows窗口的第二步

程序员文章站 2022-03-31 20:08:47
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3.5 显示窗口。

创建了窗口之后,如果要想运行时能够看见窗口,我们还需要显式的设置显示窗口:

ShowWindow(hWnd, SW_SHOW);
UpdateWindow(hWnd);

ShowWindow和UpdateWindow都是系统的API,前者是设置窗口的显示属性。后者重新更新窗口属性,只有更新之后,属性才会生效。经过了上述步骤,我们的WinMain函数已经变成了如下:

int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
_In_opt_ HINSTANCE hPrevInstance,
_In_ LPWSTR    lpCmdLine,
_In_ int       nCmdShow)
{
    //注册窗口类
    WNDCLASSEX wce = { 0 };
    wce.cbSize = sizeof(wce);
    wce.cbClsExtra = 0;
    wce.cbWndExtra = 0;
    wce.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    wce.hCursor = NULL;
    wce.hIcon = NULL;
    wce.hIconSm = NULL;
    wce.hInstance = hInstance;
    wce.lpfnWndProc = wndProc;
    wce.lpszClassName = “Main”;
    wce.lpszMenuName = NULL;
    wce.style = CS_HREDRAW | CS_VREDRAW;
    ATOM nAtom = RegisterClassEx(&wce);
    if (!nAtom )
    {
        MessageBox(NULL, "注册失败", "Infor", MB_OK);
        return 0;
    }
    
    //创建窗口 
    HWND hWnd = CreateWindowEx(0, “Main”, “Window”, WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, g_hInstance, NULL);
    //显示窗口 
   ShowWindow(hWnd, SW_SHOW); 
   UpdateWindow(hWnd); 
}

3.6 开启消息循环

所谓的消息循环,其实就是一个死循环,不断的通过GetMessage捕捉着窗口的消息,再通过TranslateMessage将虚拟键消息转换为字符消息,然后通过DispatchMessage将消息分派给我们的窗口程序进行处理(所谓处理就是调用我们定义的窗口处理函数WinProc):

void Message()
{
    MSG nMsg = { 0 };
    while (GetMessage(&nMsg, NULL, 0, 0))
    {
        TranslateMessage(&nMsg);
        DispatchMessage(&nMsg);
    }
}

完成了消息循环之后,我们最终的代码如下(这里面对窗口注册的程序进行了封装,但是过程是一致的):

#include<windows.h>
HINSTANCE g_hInstance = 0;
//窗口处理函数
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
	switch (uMsg)
	{
	case WM_DESTROY:
		PostQuitMessage(0);//可以使GetMessage返回0
		break;
	default:
		break;
	}
	return DefWindowProc(hWnd, uMsg, wParam, lParam);
}
//注册窗口类
BOOL Register(LPSTR lpClassName, WNDPROC wndProc)
{
	WNDCLASSEX wce = { 0 };
	wce.cbSize = sizeof(wce);
	wce.cbClsExtra = 0;
	wce.cbWndExtra = 0;
	wce.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
	wce.hCursor = NULL;
	wce.hIcon = NULL;
	wce.hIconSm = NULL;
	wce.hInstance = g_hInstance;
	wce.lpfnWndProc = wndProc;
	wce.lpszClassName = lpClassName;
	wce.lpszMenuName = NULL;
	wce.style = CS_HREDRAW | CS_VREDRAW;
	ATOM nAtom = RegisterClassEx(&wce);
	if (nAtom == 0)
		return FALSE;
	return true;

}
//创建主窗口
HWND CreateMain(LPSTR lpClassName, LPSTR lpWndName)
{
	HWND hWnd = CreateWindowEx(0, lpClassName, lpWndName,
		WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, g_hInstance, NULL);
	return hWnd;
}
//显示窗口
void Display(HWND hWnd)
{
	ShowWindow(hWnd, SW_SHOW);
	UpdateWindow(hWnd);
}
//消息循环
void Message()
{
	MSG nMsg = { 0 };
	while (GetMessage(&nMsg, NULL, 0, 0))
	{
		TranslateMessage(&nMsg);
		DispatchMessage(&nMsg);
	}
}
int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
	_In_opt_ HINSTANCE hPrevInstance,
	_In_ LPWSTR    lpCmdLine,
	_In_ int       nCmdShow)
{
	// TODO: Place code here.

	g_hInstance = hInstance;
	BOOL nRet = Register("Main", WndProc);
	if (!nRet)
	{
		MessageBox(NULL, "注册失败", "Infor", MB_OK);
		return 0;
	}
	HWND hWnd = CreateMain("Main", "window");
	Display(hWnd);
	Message();
	return 0;
}

就此我们完成了窗口处理的整个过程,运行程序,成功创建并显示的一个Windows窗口:

Win32 SDK基础(四)之如何从零开始创建windows窗口的第二步

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相关标签: SDK windows win32