Power-Programmierung/CD2.mdf/c/library/dos/tvision/lbox/listbox4.cpp

C/C++ Source or Header | 1992-04-16 | 10.8 KB | 367 lines

/* LISTBOX4.CPP:  Selecting a list box item

   This sample code (modified from LISTBOX3.CPP) adds a case element
   to the TMyDialog class to recognize and act upon a double click on
   a focused list box item.

   Contrary to what the Turbo Vision 1.0 manual says, a TListBox object
   does not broadcast a cmListItemSelected message to the owner.  To
   overcome this fact we create a derivitive list box (inheritance saves
   the day once again) and supply the necessary cmListItemSelected
   broadcast ourselves.

  ----------------------------------------------------------------------
   The following example routines have been provided by the Technical
   Support staff at Borland International.  They are provided as a
   courtesy and not as part of a Borland product, and as such, are
   provided without the assurance of technical support or any specific
   guarantees.
*/

#include <string.h>             // strlen()
#include <strstream.h>          // ostrstream()

#define Uses_TApplication
#define Uses_TBackground
#define Uses_TButton
#define Uses_TKeys
#define Uses_TDeskTop
#define Uses_TDialog
#define Uses_TListBox
#define Uses_TMenu
#define Uses_TMenuBar
#define Uses_TMenuItem
#define Uses_TRect
#define Uses_TInputLine
#define Uses_TScrollBar
#define Uses_TStaticText
#define Uses_TStatusDef
#define Uses_TStatusItem
#define Uses_TStatusLine
#define Uses_TStringCollection
#define Uses_MsgBox
#include <tv.h>
#include <stdlib.h>

// A NULL terminated list of strings
char *theList[] = { "Ecologic Envoy, The",
                    "Squares of the City, The",
                    "Worthing Saga, The",
                    "Arachne", NULL };

const cmAbout   = 100;  // User selected menu item 'About'
const cmList    = 101;  // User selected menu item 'List'

int ifWidth     = 35;   // input line width

//////////////////////////////////////////// TMyListBox //////////////////
class TMyListBox : public TListBox {
    public:
    TMyListBox(TRect& bounds, ushort num, TScrollBar *bar)
               :TListBox(bounds, num, bar) {};
    void handleEvent(TEvent&);
    protected:
    private:
};


/*========================================== TMyListBox ==================
   handleEvent - because the TListBox class isn't broadcasting item
                 selection, we supply the necessary functionality in our
                 derivitive list box event handler.

     REQUIRES:
     RETURNS:
*/

void TMyListBox::handleEvent(TEvent& event) {

  if ((event.what == evMouseDown) && (event.mouse.doubleClick)) {
    message(owner, evBroadcast, cmListItemSelected, this);
    clearEvent(event);
  }

  TListBox::handleEvent(event);
} // end of TMyListBox::handleEvent()


//////////////////////////////////////////// TMyDialog ///////////////////
class TMyDialog : public TDialog {
    public:
        TMyDialog(TRect &trect, int cols, char *title, char *sarray[]);
    void handleEvent(TEvent &);
    void deleteString();
    void addString();

  protected:
    private:
    TInputLine *inputLine;
    TMyListBox *listBox;                // Use our list box
    TScrollBar *listScroller;
    TStringCollection *theCollection;
};


//==========================================[ MyDialogBox ]===============
TMyDialog::TMyDialog(TRect &trect, int cols, char *title, char *sarray[])
                    :TDialog(trect, title),
                     TWindowInit(&TDialog::initFrame) {

  // Must have at least one column!
  if (!cols) cols = 1;

  // Build a collection to pass to the listbox.
  theCollection = new TStringCollection(100, 10);
  for (int i=0; sarray[i]; i++)
    theCollection->insert(sarray[i]);

  options |= ofCentered;

  int lbwidth = (trect.b.x - trect.a.x) - 3;
  int lbhite = (trect.b.y - trect.a.y) - 2;

  // If more than 1 column requested, create a horizontal scroll bar
  // else create a vertical scroll bar for the list box.
  if (cols > 1)
    listScroller = new TScrollBar(TRect(trect.a.x+3, trect.a.y+lbhite,
                                  trect.a.x+lbwidth, trect.a.y+lbhite+1));
  else
    listScroller = new TScrollBar(TRect(trect.a.x+lbwidth, trect.a.y+3,
                                  trect.a.x+lbwidth+1, trect.a.y+lbhite));

  // Create a list box with 'cols' columns and an associated scroller.
  // NOTE:  we are now using our derivitive list box
  listBox = new TMyListBox(TRect(trect.a.x+3, trect.a.y+3,
                                 trect.a.x+lbwidth, trect.a.y+lbhite),
                                 cols, listScroller);

  // Associate the collection with the list box.
  listBox->newList(theCollection);

  // Create input line.
  inputLine = new TInputLine(TRect(trect.a.x+3, trect.a.y+2,
                                   trect.a.x+lbwidth+1, trect.a.y+3),
                                   ifWidth);

  // Insert list box, its scroller and the input line into dialog box.
  insert(listBox);
  insert(listScroller);
  insert(inputLine);
} // end of MyDialogBox::MyDialogBox()


/*========================================== MyDialogBox =================
     handleEvent -
*/

void TMyDialog::handleEvent(TEvent &event) {

    switch(event.what) {
    case evKeyDown:
          switch(event.keyDown.keyCode) {

        // [Enter] with input line focused puts string in list.
              case kbEnter:
          if (inputLine->state&sfSelected) {
                  addString();
                  clearEvent(event);
          }
                break;

        // [Delete] deletes focused data
              case kbDel:
          if (listBox->state&sfSelected && theCollection->getCount()) {
                    deleteString();
                    clearEvent(event);
          }
                  break;

        // Down arrow while in line input editor moves into listbox.
              case kbDown:
          if (inputLine->state&sfSelected) {
            listBox->focusItem(0);
            event.keyDown.keyCode = kbTab;
          }
                  break;

        // Up arrow when top entry of listbox has focus moves into
        // line input editor.
              case kbUp:
          if (listBox->focused == 0 && listBox->state&sfSelected)
            event.keyDown.keyCode = kbTab;
                  break;
      }

      case evBroadcast:
        switch (event.message.command) {

          // Handle user selected list box item.
          case cmListItemSelected:
            char selItem[81];
            char message[201];

            // Get the item string,...
            listBox->getText(selItem, listBox->focused, 80);

            // ...compose a message using it to...
            ostrstream(message, 200) << "\003The item selected was "
                                     << selItem << ends;

            // ...display in a message box then clear this event.
            messageBox(message, mfOKButton|mfInformation);
            clearEvent(event);
        }
  }

    // Let TDialog handler do it's thing with any remaining events.
    TDialog::handleEvent(event);
    clearEvent(event);                                // Dood it so dump command.
} // end of MyDialogBox::eventHandler()


/*========================================== TMyDialog ===================
     deleteString - Pressing [Delete] while a list box item is focused
                  deletes that item from the list.
*/

void TMyDialog::deleteString() {

  // If there are any items in collection...
    if (theCollection->getCount()) {

    // delete the currently focused item.
        theCollection->atFree(listBox->focused);
        listBox->setRange(theCollection->getCount());
        listBox->drawView();
    }
}


/*========================================== TMyDialog ===================
     addString - Pressing Enter with the input line focused adds the
               string (if any) on the input line to the list box. The
               input line is then cleared.
*/

void TMyDialog::addString() {

    char *temp = new char[ifWidth+1];
    inputLine->getData(temp);

  // If there's anything to transfer to theCollection...
    if (strlen(temp)) {

    // ...transfer it.
        theCollection->insert(temp);
        listBox->setRange(theCollection->getCount());
        listBox->drawView();

    // Clear input line buffer, display & re-select.
        *inputLine->data='\0';
    inputLine->draw();
        inputLine->selectAll(True);
    }
  else

    // If nothing to insert, throw away the allocation.
    delete temp;
} // end of TMyDialog::addString()


//////////////////////////////////////////// TApp ////////////////////////
class TApp : public TApplication {
  public:
    TApp();
    static TMenuBar *initMenuBar(TRect r);
    void handleEvent(TEvent &event);

    void AboutDialog();
    void ListDialog();

  protected:
  private:
};


//==========================================[ TApp ]======================
TApp::TApp() : TProgInit(&TApplication::initStatusLine,
                         &TApp::initMenuBar,
                         &TApplication::initDeskTop) {
}


//=========================================== TApp =======================
TMenuBar *TApp::initMenuBar(TRect r) {

  r.b.y = r.a.y + 1;
  return(new TMenuBar(r, new TMenu(
    *new TMenuItem("~A~bout", cmAbout, kbAltA, hcNoContext, 0,
      new TMenuItem("~L~ist", cmList, kbAltL, hcNoContext, 0)))));
}


//=========================================== TApp =======================
void TApp::handleEvent(TEvent &event) {

  TApplication::handleEvent(event);
  if (event.what == evCommand) {
    switch(event.message.command) {
      case cmAbout:                     // display the about box
        AboutDialog();
        clearEvent(event);
        break;
      case cmList:                      // display our list box
        ListDialog();
        clearEvent(event);
        break;
    }
  }
}


/*=========================================== TApp =======================
   AboutDialog - create modal About dialog box
*/

void TApp::AboutDialog() {

  // the About box reminds the user what is being demonstrated
  TDialog *pd = new TDialog(TRect(0, 0, 35, 12), "About");
  if (pd) {
    pd->options |= ofCentered;
    pd->insert(new TStaticText(TRect(1, 2, 34, 7),
               "\003Turbo Vision Example\n\003\n"
               "\003Selecting List Box item\n\003\n"
               "\003Borland Technical Support"));
    pd->insert(new TButton(TRect(3, 9, 32, 11), "~O~k", cmOK, bfDefault));
        deskTop->execView(pd);
  }
  destroy(pd);
}


/*=========================================== TApp =======================
   ListDialog - display a dialog box containing a listbox
*/

void TApp::ListDialog() {

  TMyDialog *pd = new TMyDialog(TRect(0, 0, 35, 15),
                                1, "SF List", theList);

  // if the object was safely built, exec it as modal
  if (validView(pd)) deskTop->execView(pd);

  // and a little clean up
  destroy(pd);
}

//************************************************************************
int main(void) {

  // Your standard Turbo Vision main().
  TApp myApp;
  myApp.run();
  return 0;
}