How to create an instance of a class derived from CActive class?

[sumitv]

Hi,

I have derived one class from CActive class. For example,
class CClientApp : public CActive
{
private:
CTelephony* iTelephony;
CTelephony::TBatteryInfoV1 iBatteryInfoV1;
CTelephony::TBatteryInfoV1Pckg iBatteryInfoV1Pckg;

public:
CClientApp(CTelephony* aTelephony);
void SomeFunction();

private:
void RunL();
void DoCancel();
};

Now I want to create an instance of the derived class CClientApp.
How should I create it?

I have written the code as:

{
CTelephony *telephonyApi;
telephonyApi = CTelephony::NewLC();

CClientApp *batteryStrength;
batteryStrength = new CClientApp(telephonyApi);
}

//The constructor for the derived class CClientApp
CClientApp::CClientApp(CTelephony* aTelephony)
: CActive(EPriorityStandard),
iTelephony(aTelephony),
iBatteryInfoV1Pckg(iBatteryInfoV1)
{
//default constructor
iBatteryInfoV1.iStatus = CTelephony::EPowerStatusUnknown;
}

After compiling the program I am getting some linker error saying "undefined reference to vtable for CClientApp::CClientApp(CTelephony *iTelephony)"

where I am wrong? Do I need to create an instance of CActive class also?
Please help me.

Waiting for your reply,
---Sumit

[myohol]

You really should not do this
...
CClientApp *batteryStrength;
batteryStrength = new CClientApp(telephonyApi);
...

on a C-type class (especially when inherited from another C-type class). You need to do the two-phase construction stuff with NewLC & ConstructL

Other option might be using
...
batteryStrength = new (ELeave)CClientApp(telephonyApi);
...

[sumitv]

Thank you.

I have changed my code to new (ELeave).

---Sumit

[skumar_rao]

batteryStrength = new (ELeave)CClientApp(telephonyApi);

I recommend to use NewL for every C-Class.

[navjotsingh1979]

hi sumitv,

there is some error indicating to 'vtable '.

so check that you have implemented all the pure virtual functions (owned from the base) in the derived class you are trying to instantiate.

Ensure that you have implemented the RunL() in the derived class .


regards
nEo

[skumar_rao]

//The constructor for the derived class CClientApp
CClientApp::CClientApp(CTelephony* aTelephony)
: CActive(EPriorityStandard),
iTelephony(aTelephony),
iBatteryInfoV1Pckg(iBatteryInfoV1)
{
//default constructor
iBatteryInfoV1.iStatus = CTelephony::EPowerStatusUnknown;
}

For the vtable Error You are getting i don't think you req. this.
cahange it to

//The constructor for the derived class CClientApp
CClientApp::CClientApp(CTelephony* aTelephony)
    : CActive(EPriorityStandard),
      iTelephony(aTelephony)
    {
    //default constructor
    	iBatteryInfoV1.iStatus = CTelephony::EPowerStatusUnknown;
    }

[sumitv]

hi sumitv,

there is some error indicating to 'vtable '.

so check that you have implemented all the pure virtual functions (owned from the base) in the derived class you are trying to instantiate.

Ensure that you have implemented the RunL() in the derived class .


regards
nEo

Yes the error is solved.
Your are write. I had declared the functions RunL() and DoCancel() in the derived class but I did not implement that.

Now I have written the function definitions for both the functions RunL() and DoCancel().
And IT WORKS!!![]

The error is resolved.

Thanking you,
---Sumit