Symbian programming - Displaying controls in exe programs

Displaying controls in Symbian exe programs.

You may want to refer to this article for some background on this topic before continuing.

If we now wanted to create and display a CCoeControl, we'd need to have a CONE environment (CCoeEnv) as a minimum, as this class is used internally by the control. This makes things easier, given that CCoeEnv, as its name implies, creates a whole environment for us, thus limiting our task to the proper control creation:

#include <coedef.h>      // TCoeWinPriority
#include <e32base.h>    // CTrapCleanup
#include <w32std.h>     // RWsSession
#include <coecntrl.h>    // CCoeControl
#include <coemain.h>    // CCoeEnv

class CMyControl : public CCoeControl
{
public:
    void ConstructL(const TRect& aRect);

private:
    void Draw(const TRect& aRect) const;
};

void CMyControl::ConstructL(const TRect& aRect)
{
    CreateWindowL();

    SetRect(aRect);
    ActivateL();
}

void CMyControl::Draw(const TRect& aRect) const
{
    // Just paint it blue

    CWindowGc& gc = SystemGc();
    gc.SetBrushStyle(CGraphicsContext::ESolidBrush);
    gc.SetBrushColor(KRgbBlue);
    gc.SetPenStyle(CGraphicsContext::ENullPen);

    gc.Clear(aRect);
}

// S60 screen size
const TUint screenWidth  = 176;
const TUint screenHeight = 208;

LOCAL_C void ExeMainL()
{
    CCoeEnv::Static()->RootWin().SetOrdinalPosition(0, ECoeWinPriorityAlwaysAtFront);

    CMyControl* ctrl = new(ELeave) CMyControl;
    CleanupStack::PushL(ctrl);

    ctrl->ConstructL(TRect(0, 0, screenWidth, screenHeight));
    ctrl->DrawNow();

    CCoeEnv::Static()->WsSession().Flush();

    CleanupStack::PopAndDestroy(ctrl);
}

GLDEF_C TInt E32Main()
{
#if defined(__WINS__)
    // WINS already creates environment for us
    CCoeEnv* coe = CCoeEnv::Static();
#else
    CCoeEnv* coe = new CCoeEnv;
    TRAPD(err, coe->ConstructL());
    __ASSERT_ALWAYS(!err, User::Panic(_L("EXECTRL"), err));
#endif

    TRAPD(error, ExeMainL());
    __ASSERT_ALWAYS(!error, User::Panic(_L("EXECTRL"), error));

    User::After(3*1000*1000);

#if !defined(__WINS__)
    coe->DestroyEnvironment();
#endif

    return 0;
}

#if defined(__WINS__)
EXPORT_C TInt WinsMain()
{
    E32Main();
    User::Exit(0);
    return KErrNone;
}

TInt E32Dll(TDllReason)
{
    return KErrNone;
}
#endif

Note that the emulator creates on our behalf an environment when loading an exedll/epocexe as .app, so we have to avoid creating a new environment on emulator builds, otherwise, we'd get a CONE 2 panic (Environment already exists)

Now moving a step further, we'd like to use existing controls, such as listboxes, dialogs, etc. In most cases, a CONE environment won't be enough, so we'll have to resort on the Eikon environment:

#include <coedef.h>      // TCoeWinPriority
#include <e32base.h>    // CTrapCleanup
#include <w32std.h>     // RWsSession
#include <coecntrl.h>    // CCoeControl
#include <eikenv.h>      // CEikonEnv
#include <eiktxlbx.h>     // CEikTextListBox
#include <eiktxlbm.h>    // CTextListBoxModel

class CMyControl : public CCoeControl
{
public:
    void ConstructL(const TRect& aRect);
    ~CMyControl();

private:
    void SizeChanged();
    TInt CountComponentControls() const;
    CCoeControl* ComponentControl(TInt aIndex) const;

    void Draw(const TRect& aRect) const;

private:
    CEikTextListBox* iListBox;
};

void CMyControl::ConstructL(const TRect& aRect)
{
    CreateWindowL();

    // You may use CAknSingleStyleListBox, etc for Series 60..
    iListBox = new(ELeave) CEikTextListBox;
    iListBox->SetContainerWindowL(*this);
//    iListBox->SetMopParent(this);
    iListBox->ConstructL(this);

    CDesCArray* items = static_cast<CDesCArray*> (iListBox->Model()->ItemTextArray());
    _LIT(KItem1, "First");
    items->AppendL(KItem1);
    _LIT(KItem2, "Second");
    items->AppendL(KItem2);

    iListBox->HandleItemAdditionL();
    iListBox->SetFocus(ETrue);

//    iListBox->CreateScrollBarFrameL();
//    iListBox->ScrollBarFrame()->SetScrollBarVisibilityL(CEikScrollBarFrame::EOff, CEikScrollBarFrame::EAuto);

    SetRect(aRect);
    ActivateL();
}

CMyControl::~CMyControl()
{
    delete iListBox;
}

void CMyControl::SizeChanged()
{
    iListBox->SetRect(Rect());
}

TInt CMyControl::CountComponentControls() const
{
    return 1;
}

CCoeControl* CMyControl::ComponentControl(TInt aIndex) const
{
    switch (aIndex)
    {
        case 0:
            return iListBox;

        default:
            return 0;
    }
}

void CMyControl::Draw(const TRect& aRect) const
{
    CWindowGc& gc = SystemGc();
    gc.Clear(aRect);
}

// S60 screen size
const TUint screenWidth  = 176;
const TUint screenHeight = 208;

LOCAL_C void ExeMainL()
{
    CCoeEnv::Static()->RootWin().SetOrdinalPosition(0, ECoeWinPriorityAlwaysAtFront);

    CMyControl* ctrl = new(ELeave) CMyControl;
    CleanupStack::PushL(ctrl);

    ctrl->ConstructL(TRect(0, 0, screenWidth, screenHeight));
    ctrl->DrawNow();

    CCoeEnv::Static()->WsSession().Flush();

    CleanupStack::PopAndDestroy(ctrl);
}

GLDEF_C TInt E32Main()
{
#if defined(__WINS__)
    // WINS already creates environment for us
    CEikonEnv* coe = CEikonEnv::Static();
#else
    CEikonEnv* coe = new CEikonEnv;
    TRAPD(err, coe->ConstructL());
    __ASSERT_ALWAYS(!err, User::Panic(_L("EXECTRL"), err));
#endif

    TRAPD(error, ExeMainL());
    __ASSERT_ALWAYS(!error, User::Panic(_L("EXECTRL"), error));

    User::After(3*1000*1000);

#if !defined(__WINS__)
    delete coe;
#endif

    return 0;
}

#if defined(__WINS__)
EXPORT_C TInt WinsMain()
{
    E32Main();
    User::Exit(0);
    return KErrNone;
}

TInt E32Dll(TDllReason)
{
    return KErrNone;
}
#endif

The example above shows a pretty simple compound control, consisting of just one lodger control, a text listbox. But to make this a bit more useful, we'd need to receive events (such as key presses) and pass them to the control. The example bellow shows a simple implementation. Actually, it mimics somehow CCoeEnv::ExecuteD() functionality, which basically starts the active scheduler and waits for events from the window server (note that CCoeEnv is a CActive)

LOCAL_C void ExeMainL()
{
    CCoeEnv* coeEnv = CCoeEnv::Static();
    coeEnv->RootWin().SetOrdinalPosition(0, ECoeWinPriorityAlwaysAtFront);

    CMyControl* ctrl = new(ELeave) CMyControl;
    CleanupStack::PushL(ctrl);

    ctrl->ConstructL(TRect(0, 0, screenWidth, screenHeight));
    ctrl->DrawNow();

    coeEnv->WsSession().Flush();

    // Create a basic UI and set control to receive events
    CMyAppUi* appUi = new(ELeave) CMyAppUi;
    appUi->SetRootControl(ctrl);
    coeEnv->SetAppUi(appUi);    // takes ownership

    for (;;)
    {
        // Wait synchronously for event
        TRequestStatus status;
        coeEnv->WsSession().EventReady(&status);
        User::WaitForRequest(status);

        if (status.Int() == KErrNone)
        {
            TWsEvent event;
            coeEnv->WsSession().GetEvent(event);

            // Check exit key
            if (event.Key()->iCode == EKeyDevice3)
                break;

            // Pass event to control
            appUi->HandleWsEventL(event, ctrl);
        }
    }

    CleanupStack::PopAndDestroy(ctrl);
}

You may download the examples here:
ExeCtrl.zip (CONE environment)
ExeCtrl.zip (Eikon environment)

All emulator builds have been compiled & linked using Microsoft Visual C++ 6.0 compiler. In some cases, some small changes might be required to make it work with your toolchain. I'm not responsible for your use of the information contained in or linked from these web pages.