这是我的解决方案。我选择使用Motif(OpenMotif),因为它只需要相对较少的额外库(Xm、Xt、X11)。根据消息大小,我的实现会打开一个简单的消息框或一个更复杂的对话框,其中包含一个不可编辑的可滚动文本(后者来自Motif程序员手册,并为我的目的进行了调整)。
包含文件和全局数据:
#include <Xm/Xm.h>
#include <Xm/MwmUtil.h>
#include <Xm/MainW.h>
#include <Xm/CascadeB.h>
#include <Xm/MessageB.h>
#include <Xm/RowColumn.h>
#include <Xm/Form.h>
#include <Xm/PushBG.h>
#include <Xm/LabelG.h>
#include <Xm/PanedW.h>
#include <Xm/Text.h>
#include <Xm/DialogS.h>
#include <Xm/Command.h>
static XtAppContext appShell;
一个用于确定文本消息行数和最大列数的辅助函数:
static int MsgSize (char* pszMsg, int& nCols)
{
if (!(pszMsg && *pszMsg))
return 0;
int nRows = 1;
nCols = 0;
for (char* p = pszMsg; *p && (pszMsg = strchr (p, '\n')); nRows++, p = ++pszMsg) {
if (nCols < pszMsg - p)
nCols = pszMsg - p;
}
return nRows;
}
消息对话框关闭按钮的回调函数:
void DestroyShell (Widget widget, XtPointer clientData, XtPointer callData)
{
Widget shell = (Widget) clientData;
XtDestroyWidget (shell);
XtAppSetExitFlag (appShell);
}
构建一个对话框,其中包含一个可滚动的、不可编辑的文本小部件和一个关闭按钮。该内容源自Motif程序员手册,并稍作修改(无图标,单个按钮,最小窗口装饰)。
void XmMessageDialog (const char* pszMsg, int nRows, int nCols, bool bError)
{
Widget msgBox, pane, msgText, form, widget;
void DestroyShell(Widget, XtPointer, XtPointer);
Arg args [10];
int n = 0;
int i;
Dimension h;
Widget topWid = XtVaAppInitialize (&appShell, "D2X-XL", NULL, 0, &argc, argv, NULL, NULL);
XtSetArg (args [0], XmNdeleteResponse, XmDESTROY);
msgBox = XmCreateDialogShell (topWid, bError ? const_cast<char*>("Error") : const_cast<char*>("Warning"), args, 1);
XtVaGetValues (msgBox, XmNmwmDecorations, &i, NULL);
i &= ~(MWM_DECOR_ALL | MWM_DECOR_MINIMIZE | MWM_DECOR_MAXIMIZE | MWM_DECOR_MENU);
XtVaSetValues (msgBox, XmNmwmDecorations, i, NULL);
XtVaGetValues (msgBox, XmNmwmFunctions, &i, NULL);
i &= ~(MWM_FUNC_ALL | MWM_FUNC_MINIMIZE | MWM_FUNC_MAXIMIZE | MWM_FUNC_CLOSE);
XtVaSetValues (msgBox, XmNmwmFunctions, i, NULL);
XtSetArg (args [0], XmNsashWidth, 1);
XtSetArg (args [1], XmNsashHeight, 1);
pane = XmCreatePanedWindow (msgBox, const_cast<char*>("pane"), args, 2);
form = XmCreateForm (pane, const_cast<char*>("form1"), NULL, 0);
n = 0;
XtSetArg (args [n], XmNscrollVertical, True); n++;
XtSetArg (args [n], XmNscrollHorizontal, False); n++;
XtSetArg (args [n], XmNeditMode, XmMULTI_LINE_EDIT); n++;
XtSetArg (args [n], XmNeditable, False); n++;
XtSetArg (args [n], XmNcursorPositionVisible, False); n++;
XtSetArg (args [n], XmNwordWrap, True); n++;
XtSetArg (args [n], XmNvalue, pszMsg); n++;
XtSetArg (args [n], XmNrows, min (nRows, 30)); n++;
XtSetArg (args [n], XmNcolumns, min (nCols, 120)); n++;
msgText = XmCreateScrolledText (form, const_cast<char*>("help_text"), args, n);
XtVaSetValues (XtParent (msgText),
XmNleftAttachment, XmATTACH_FORM,
XmNtopAttachment, XmATTACH_FORM,
XmNrightAttachment, XmATTACH_FORM,
XmNbottomAttachment, XmATTACH_FORM,
NULL);
XtManageChild (msgText);
XtManageChild (form);
XtSetArg (args [0], XmNfractionBase, 5);
form = XmCreateForm (pane, const_cast<char*>("form2"), args, 1);
widget = XmCreatePushButtonGadget (form, const_cast<char*>("Close"), NULL, 0);
XtVaSetValues (widget,
XmNtopAttachment, XmATTACH_FORM,
XmNbottomAttachment, XmATTACH_FORM,
XmNleftAttachment, XmATTACH_POSITION,
XmNleftPosition, 2,
XmNrightAttachment, XmATTACH_POSITION,
XmNrightPosition, 3,
XmNshowAsDefault, True,
XmNdefaultButtonShadowThickness, 1,
NULL);
XtManageChild (widget);
XtAddCallback (widget, XmNactivateCallback, DestroyShell, (XtPointer) msgBox);
XtManageChild (form);
XtVaGetValues (widget, XmNheight, &h, NULL);
XtVaSetValues (form, XmNpaneMaximum, h, XmNpaneMinimum, h, NULL);
XtManageChild (pane);
}
消息框“确定”按钮的回调函数
void XmCloseMsgBox (Widget w, XtPointer clientData, XtPointer callData)
{
XtAppSetExitFlag (appShell);
}
决定使用简单或高级消息框,显示其中任意一个,并在用户单击其关闭/确定按钮时将其删除。
void XmMessageBox (const char* pszMsg, bool bError)
{
Widget topWid;
int nRows, nCols;
nRows = MsgSize (const_cast<char*>(pszMsg), nCols);
if ((nRows > 3) || (nCols > 360))
XmMessageDialog (pszMsg, nRows, nCols, bError);
else {
topWid = XtVaAppInitialize (&appShell, "D2X-XL", NULL, 0, &argC, argv, NULL, NULL);
Arg args [1];
XmString xmString = XmStringCreateLocalized (const_cast<char*>(pszMsg));
XtSetArg (args [0], XmNmessageString, xmString);
Widget xMsgBox = bError
? XmCreateErrorDialog (topWid, const_cast<char*>("Error"), args, 1)
: XmCreateWarningDialog (topWid, const_cast<char*>("Warning"), args, 1);
XmStringFree (xmString);
XtUnmanageChild (XmMessageBoxGetChild (xMsgBox, XmDIALOG_CANCEL_BUTTON));
XtUnmanageChild (XmMessageBoxGetChild (xMsgBox, XmDIALOG_HELP_BUTTON));
XtAddCallback (xMsgBox, XmNokCallback, XmCloseMsgBox, NULL);
XtManageChild (xMsgBox);
XtRealizeWidget (topWid);
}
XtAppMainLoop (appShell);
XtUnrealizeWidget (topWid);
XtDestroyApplicationContext (appShell);
}