windows(3)修改視窗類實現文字的切換
阿新 • • 發佈:2019-01-08
【摘要】這節課的主要內容是將如何修改視窗類,也就是修改一個建立好的視窗類。本節課實現修改我們自己建立的視窗類,來達到閃爍的文字和視窗背景顏色的效果。當然也可以修改系統建立的視窗類。
修改視窗類,系統已經提供了API函式SetWindowLong。它可以修改已經建立的視窗的風格、視窗過程、視窗ID和視窗關聯的資料。
修改的實現過程很簡單。我們利用這個修改,可以隨意切換視窗處理過程。只要修改一下視窗過程,視窗的訊息就會發送到新的視窗過程中處理了。
首先,準備好一個視窗過程。自己提供的視窗過程中,包含了另外一套訊息處理。和原先的視窗過程一起,一共有兩套了。
然後通過使用SetWindowLong(hwnd, GWL_WNDPROC, (LONG)新視窗過程函式名),這樣就可以重新設定了。SetWindowLong需要設定的視窗控制代碼,所以,你要等開始的視窗已經建立成功了,才能設定,不然你無法獲取視窗控制代碼咯。你也可以等視窗創建出來後再給視窗類修改視窗過程,也可以建立視窗後,修改視窗類的視窗過程,然後再顯示視窗
總結:SetWindowLong(hwnd, GWL_WNDPROC, (LONG)新視窗過程函式名)該函式可以修改視窗過程函式。一般來說,當一個視窗類建立的時候,視窗過程函式就隨之確定。我們可以通過這個修改函式使視窗類執行另外的視窗過程函式。#include <Windows.h> #include <tchar.h> LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); LRESULT CALLBACK MyProc(HWND, UINT, WPARAM, LPARAM); int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrev, PSTR szCmdLine, int iCmdShow) { static TCHAR szExeName[] = _T("Win32"); HWND hwnd; MSG msg; WNDCLASS wndclass; wndclass.style = CS_HREDRAW | CS_VREDRAW; wndclass.lpfnWndProc = WndProc; wndclass.cbClsExtra = 0; wndclass.cbWndExtra = 0; wndclass.hInstance = hInstance; wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION); wndclass.hCursor = LoadCursor(NULL, IDC_ARROW); wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH); wndclass.lpszMenuName = NULL; wndclass.lpszClassName = szExeName; if (!RegisterClass(&wndclass)) { MessageBox(NULL, _T("註冊視窗類失敗,此程式需要執行在Windows NT平臺下。"), szExeName, MB_ICONERROR); return 0; } hwnd = CreateWindow(szExeName, _T("我的視窗標題_C++技術網"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL); SetWindowLong(hwnd, GWL_WNDPROC, (LONG)MyProc); ShowWindow(hwnd, iCmdShow); UpdateWindow(hwnd); while (GetMessage(&msg, NULL, 0, 0)) { TranslateMessage(&msg); DispatchMessage(&msg); } return msg.wParam; } LRESULT CALLBACK MyProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { HDC hdc; PAINTSTRUCT ps; RECT rect; static int i = 0; WCHAR szTip[100] = { 0 }; switch (message) { case WM_CREATE: MessageBox(NULL, _T("視窗正在建立"), _T("win32"), MB_ICONINFORMATION); SetTimer(hwnd, 0, 1000, NULL); return 0; case WM_PAINT: hdc = BeginPaint(hwnd, &ps); GetClientRect(hwnd, &rect); SetBkColor(hdc, RGB(0, 0, 255)); SetTextColor(hdc, RGB(255, 0, 0)); FillRect(GetWindowDC(hwnd), &rect, (HBRUSH)GetStockObject(WHITE_BRUSH)); DrawText(hdc, _T("Win32程式介面,初始化視窗過程"), -1, &rect, DT_SINGLELINE | DT_CENTER | DT_VCENTER); SetWindowLong(hwnd, GWL_WNDPROC, (LONG)WndProc);//- 切換視窗過程 swprintf(szTip,100, _T("計時:%d"), i); DrawText(hdc, szTip, -1, &rect, DT_SINGLELINE | DT_CENTER); EndPaint(hwnd, &ps); return 0; case WM_DESTROY: MessageBox(NULL, _T("程式即將結束!"), _T("win32"), MB_ICONINFORMATION); KillTimer(hwnd, 0); PostQuitMessage(0); return 0; case WM_TIMER: GetClientRect(hwnd, &rect); InvalidateRect(hwnd, &rect, true); i++; return 0; } return DefWindowProc(hwnd, message, wParam, lParam); } LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { HDC hdc; PAINTSTRUCT ps; RECT rect; static int i = 0; WCHAR szTip[100] = { 0 }; switch (message) { case WM_CREATE: MessageBox(NULL, _T("視窗正在建立"), _T("win32"), MB_ICONINFORMATION); SetTimer(hwnd, 0, 1000, NULL); return 0; case WM_PAINT: hdc = BeginPaint(hwnd, &ps); GetClientRect(hwnd, &rect); SetBkColor(hdc, RGB(0, 0, 255)); SetTextColor(hdc, RGB(255, 0, 0)); FillRect(GetWindowDC(hwnd), &rect, (HBRUSH)GetStockObject(WHITE_BRUSH)); DrawText(hdc, _T("Win32程式介面,初始化視窗過程"), -1, &rect, DT_SINGLELINE | DT_CENTER | DT_VCENTER); SetWindowLong(hwnd, GWL_WNDPROC, (LONG)MyProc);//- 切換視窗過程 swprintf(szTip,100, _T("計時:%d"), i); DrawText(hdc, szTip, -1, &rect, DT_SINGLELINE | DT_CENTER); EndPaint(hwnd, &ps); return 0; case WM_DESTROY: MessageBox(NULL, _T("程式即將結束!"), _T("win32"), MB_ICONINFORMATION); KillTimer(hwnd, 0); PostQuitMessage(0); return 0; case WM_TIMER: GetClientRect(hwnd, &rect); InvalidateRect(hwnd, &rect, true); i++; return 0; } return DefWindowProc(hwnd, message, wParam, lParam); }