Creating a dynamic form in Palm OS

Code below shows how to create a dynamic form for Palm OS 3.0 or greater. See this link of the entire project created using Palm OS Development Suite.

/******************************************************************************
* Application Name    : DynamicUI.prc
* Purpose             : Demonstrate how to create a dynamic UI
* Programmed by       : Techno Scavenger
*****************************************************************************/

#include <PalmOS.h>

/***********************************************************************
*
*  Internal Constants
*
***********************************************************************/
#define appFileCreator      'ewa8'
#define appVersionNum       0x01
#define appPrefID           0x00
#define appPrefVersionNum   0x01

/***********************************************************************
*
*  Application constants
*
***********************************************************************/
#define MainForm        1000

/***********************************************************************
* FUNCTION:    MainFormHandleEvent
* DESCRIPTION: This routine is the event handler for the
*              "MainForm" of this application.
* PARAMETERS:  pEvent  - a pointer to an EventType structure
* RETURNED:    true if the event has handle and should not be passed
*              to a higher level handler.
* REVISION HISTORY:
***********************************************************************/
static Boolean MainFormHandleEvent(EventType* pEvent)
{
 Boolean   handled = false;
 FormType*   pForm;

 switch (pEvent->eType) {
   case frmOpenEvent:
     pForm = FrmGetActiveForm();
     FrmDrawForm(pForm);
     handled = true;
     break;
    
   default:
     break;
 }

 return handled;
}

/***********************************************************************
* FUNCTION:    AppHandleEvent
* DESCRIPTION: This routine loads form resources and set the event
*              handler for the form loaded.
* PARAMETERS:  event  - a pointer to an EventType structure
* RETURNED:    true if the event has handle and should not be passed
*              to a higher level handler.
* REVISION HISTORY:
***********************************************************************/
static Boolean AppHandleEvent(EventType* pEvent)
{
 UInt16    formId;
 FormType*   pForm;
 Boolean   handled = false;

 if (pEvent->eType == frmLoadEvent) {
   formId = pEvent->data.frmLoad.formID;
  
//    pForm = FrmInitForm(formId);
    pForm = FrmGetFormPtr(MainForm);
   FrmSetActiveForm(pForm);

   // Set the event handler for the form.  The handler of the currently
   // active form is called by FrmHandleEvent each time is receives an
   // event.
    switch (formId) {
     case MainForm:
       FrmSetEventHandler(pForm, MainFormHandleEvent);
       break;

     default:
       break;
   }
   handled = true;
 }

 return handled;
}


/***********************************************************************
* FUNCTION:    AppEventLoop
* DESCRIPTION: This routine is the event loop for the application. 
* PARAMETERS:  nothing
* RETURNED:    nothing
* REVISION HISTORY:
***********************************************************************/
static void AppEventLoop(void)
{
 Err     error;
 EventType event;

 do {
   EvtGetEvent(&event, evtWaitForever);

   if (SysHandleEvent(&event))
     continue;
    
   if (MenuHandleEvent(0, &event, &error))
     continue;
    
   if (AppHandleEvent(&event))
     continue;

   FrmDispatchEvent(&event);

 } while (event.eType != appStopEvent);
}

/***********************************************************************
* FUNCTION:     AppStart
* DESCRIPTION:  Get the current application's preferences.
* PARAMETERS:   nothing
* RETURNED:     Err value errNone if nothing went wrong
* REVISION HISTORY:
***********************************************************************/
static Err AppStart(void)
{

//  FrmGotoForm(MainForm);
  static Char strTitle[13] = "Dynamic Form";
 FormType* pMainForm;
 pMainForm = FrmNewForm( MainForm, strTitle, 0, 0, 160, 160, false, 0, 0, 0);
 FrmGotoForm(MainForm);
 return errNone;
}

/***********************************************************************
* FUNCTION:          AppStop
* DESCRIPTION:       Save the current state of the application.
* PARAMETERS:        nothing
* RETURNED:          nothing
* REVISION HISTORY:
***********************************************************************/
static void AppStop(void)
{
 // Close all the open forms.
  FrmCloseAllForms();
}

/***********************************************************************
* FUNCTION:    PilotMain
* DESCRIPTION: This is the main entry point for the application.
* PARAMETERS:  cmd - word value specifying the launch code.
*              cmdPB - pointer to a structure that is associated with the launch code.
*              launchFlags -  word value providing extra information about the launch.
* RETURNED:    Result of launch
* REVISION HISTORY:
***********************************************************************/
UInt32 PilotMain(UInt16 cmd, MemPtr cmdPBP, UInt16 launchFlags)
{
 Err error = errNone;

 switch (cmd) {
   case sysAppLaunchCmdNormalLaunch:
     if ((error = AppStart()) == 0) {     
       AppEventLoop();
       AppStop();
     }
     break;

   default:
     break;
 }

 return error;
}