Categories: Symbian C++ | Code Examples | Files/Data | S60 3rd Edition

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Overview

This code snippet shows how to create a condition-based schedule using the class RScheduler. One condition-based schedule can contain one or more TTaskSchedulerCondition schedule entries. An entry contains criteria based on the Publish and Subscribe variable and when this variable has a certain value, the Task Scheduler server launches scheduled tasks. The user can also give a default runtime for the tasks to run regardless of the condition variable values.

In this example, a condition-based schedule with one task is created. After that, the Symbian Publish and Subscribe mechanism is used to trigger and execute the scheduled task.

This snippet can be self-signed.

MMP file

The following libraries are required:

LIBRARY             schsvr.lib

Preconditions

ExampleTaskHandler.exe must be created before this code snippet can be executed. See CS000986 - Creating and registering a task handler with RScheduler

Resource files

.rss

RESOURCE MENU_PANE r_schedulerexample_menu
    {
    items = 
        {
         //...
        MENU_ITEM {command = ECreateConditionExample;  txt = "CreateConditionExample";},
         //...
        MENU_ITEM {command = EAknSoftkeyExit;          txt = "Exit";}
        };
    }

.hrh

enum TSchedulerExampleIds
    {
    //...
    ECreateConditionExample,
     //...
    };

Header file

#ifndef __SCHEDULEREXAMPLEAPPUI_H__
#define __SCHEDULEREXAMPLEAPPUI_H__
 
#include <csch_cli.h> // RScheduler
#include <schinfo.h>  // TSchedulerItemRef, TTaskInfo... 
 
class CSchedulerExampleAppUi : public CAknAppUi
    {
    //...
public:    
    void HandleCommandL(TInt aCommand);
    //...
private:        
    void CreateConditionVariableL();
   
    void SetConditionVariableL(TInt aKeyValue); 
    
    void DeleteConditionVariableL();
 
    TInt CreateConditionScheduleWithTaskL(TSchedulerItemRef& aSchedulerItem, 
                                            RScheduler& aScheduler,
                                            const TUid& aConditionCategory,
                                            TUint aConditionKey,
                                            const TTsTime& aDefaultRunTime, 
                                            TInt& aNewTaskId);
 
    //...    
private:
 
    RScheduler iScheduler;
 
    TSchedulerItemRef iConditionScheduleHandle;    
    };
    
#endif // __SCHEDULEREXAMPLEAPPUI_H__

Source file

#include <e32property.h>
 
const TUid KExampleUid = TUid::Uid(0xE0060BBB); //UID3 from .mmp file
const TInt KExampleKey = 1;
 
void CSchedulerExampleAppUi::ConstructL()
    {
    //...
    User::LeaveIfError(iScheduler.Connect());
    
    _LIT(KExampleTaskHandlerExe, "ExampleTaskHandler.exe");
    TFileName exampleHandler(KExampleTaskHandlerExe);
        
    User::LeaveIfError(iScheduler.Register(exampleHandler, CActive::EPriorityStandard));    
    }
    
CSchedulerExampleAppUi::~CSchedulerExampleAppUi()
    {
 
    //...    
    iScheduler.Close(); 
    
    DeleteConditionVariableL(); 
    }    
 
void CSchedulerExampleAppUi::HandleCommandL(TInt aCommand)
  {
  TBuf<100> Text1; //first line of dialog text 
  TBuf<100> Text2; //second line of dialog text
      
  switch(aCommand)
    {
    case EEikCmdExit:
    case EAknSoftkeyExit:
      Exit();
      break;
//...
    case ECreateConditionExample:
      {
      TInt err(KErrNone);
         
      //create condition variable for condition-based schedule    
      CreateConditionVariableL();
             
      TSchedulerItemRef conditionScheduleHandle;
  
      TTsTime defaultTime;
      TTime time;
      time.HomeTime();
      time = time.operator+(TTimeIntervalMonths(1));
      defaultTime.SetLocalTime( time );
               
      TInt newConditionTaskId=-1;
      err = CreateConditionScheduleWithTaskL(iConditionScheduleHandle,
 iScheduler,  KExampleUid, KExampleKey, defaultTime, newConditionTaskId );
              
      if(err == KErrNone)
        {                 
        Text1.Append(_L("ConditionTask:"));
        Text1.AppendNum(newConditionTaskId);
        Text1.Append(_L(" Scheduled"));
        
        CEikonEnv::Static()->InfoWinL(Text1, _L(""));
        
        //Set condition variable and trigger task scheduler to execute the example task 
        SetConditionVariableL(1);
        }
      else
        {
        //Creating condition schedule failed, do something...
         }
       }
     break;
      
   default:
     //Panic(ESchedulerExampleUi);
     break;
     }
  }  
    
 
void CSchedulerExampleAppUi::CreateConditionVariableL()
  {
  TInt ret = RProperty::Define(KExampleUid, KExampleKey, RProperty::EInt);
  
  if (ret != KErrAlreadyExists)
    {      
    User::LeaveIfError(ret);
    }
  }
 
void CSchedulerExampleAppUi::SetConditionVariableL(TInt aKeyValue)              
  {  
  TInt ret = RProperty::Set(KExampleUid, KExampleKey, aKeyValue);
  
  User::LeaveIfError(ret);
  }
 
void CSchedulerExampleAppUi::DeleteConditionVariableL()
  {
  TInt ret = RProperty::Delete(KExampleUid, KExampleKey);
  
  if (ret != KErrNotFound)
    {
    User::LeaveIfError(ret);
    }
  }
 
//create a condition-based schedule with one example task
TInt CSchedulerExampleAppUi::CreateConditionScheduleWithTaskL(
                  TSchedulerItemRef& aSchedulerItem, 
                  RScheduler& aScheduler,
                  const TUid& aConditionCategory,
                  TUint aConditionKey,
                  const TTsTime& aDefaultRunTime,
                  TInt& aNewTaskId)
  {
  TInt ret(KErrNone);
  
  aSchedulerItem.iName = _L("Condition Schedule Example");
  
  CArrayFixFlat<TTaskSchedulerCondition>* conditions = 
new (ELeave) CArrayFixFlat<TTaskSchedulerCondition>(1);
  
  CleanupStack::PushL(conditions);
  TTaskSchedulerCondition exampleCondition;
  exampleCondition.iCategory = aConditionCategory;
  exampleCondition.iKey    = aConditionKey;
  exampleCondition.iState  = 1;
  exampleCondition.iType  = TTaskSchedulerCondition::EEquals;
  conditions->AppendL(exampleCondition);
 
  ret = aScheduler.CreatePersistentSchedule(aSchedulerItem,
                                   *conditions, aDefaultRunTime);
 
  if (ret == KErrNone)
    {
    TTaskInfo taskInfo;
    taskInfo.iTaskId = 0;
    taskInfo.iName = _L("ExampleTask3");
    taskInfo.iPriority = 2;
    taskInfo.iRepeat = 0;
    HBufC* data = _L("ExampleData3").AllocLC();
    
    // schedule the example task
    ret = aScheduler.ScheduleTask(taskInfo, *data, aSchedulerItem.iHandle);
    
    aNewTaskId = taskInfo.iTaskId;
    
    CleanupStack::PopAndDestroy(); // data
    }
  else
    {
    //Creating persistent schedule failed, do something...    
    }
 
  CleanupStack::PopAndDestroy(); // conditions
  
  return ret;
  }

Postconditions

The condition-based schedule with one example task has been created and the task execution is triggered using the Publish and Subscribe mechanism.

See also

• CS000986 - Creating and registering a task handler with RScheduler
• CS000987 - Creating persistent and transient schedules with RScheduler
• CS000989 - Getting schedule and task info using RScheduler
• CS000990 - Getting schedule and task count using RScheduler
• CS000991 - Editing a schedule using RScheduler
• CS000992 - Deleting schedules and tasks using RScheduler