Archived:Creating a condition-based schedule with RScheduler
| ID | Creation date | May 23, 2008 | |
| Platform | S60 3rd Edition, FP1 | Tested on devices | Nokia N93 |
| Category | Symbian C++ | Subcategory | Files/Data |
| Keywords (APIs, classes, methods, functions): RScheduler, TSchedulerItemRef, TTaskSchedulerCondition, TTaskInfo, TTsTime, RProperty, RScheduler::Connect(), RScheduler::Register(), RScheduler::Close(), RScheduler::CreatePersistentSchedule(), RScheduler::ScheduleTask(), TTsTime::SetLocalTime(), RProperty::Define(), RProperty::Set(), RProperty::Delete() |
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 a criteria based on Publish and Subscribe variable and when this variable has 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 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 is created and the task execution is triggered using Publish and Subscribe mechanism.
