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Nevertheless, CExampleHelloControl contains part of the size- and target-independent code: it allocates the size and device-dependent font with which to do the drawing, using an independent font specification. The reason for this is explained later. The role of each of the GDI classes is summarized below: Class Description CGraphicsContext The abstract base class created by a graphics device, CGraphicsDevice. Contains the main drawing functions. Provides the 'context' in which you are drawing to the associated device in the sense that it holds the pen and brush settings (e.g. color, line styles) and font settings (e.g. bold, underline, italic) for drawing, and also the clipping region(the visible drawing area). These can all be updated while drawing. Deals with pixels of device-dependent size and uses fonts with device-dependent size and representation. The sizes and fonts to be passed to CGraphicsContext functions therefore need to be converted from size-independent units to sizedependent units beforehand. This is done by an MGraphicsDeviceMap derived class. This may be a TZoomFactor or the CGraphicsDevice. Note that the CGraphicsContext class was described in more detail in <strong>Chapter</strong> 11 and its handling of colors and bitmaps is described later in this chapter. MGraphicsDeviceMap The abstract base class for both graphic devices and zoom factors. Defines the size-dependent functions in a graphics device. These functions convert between pixels and twips and perform font allocation and release. Font allocation involves finding the font supported by the device that is the closest to a deviceindependent font specification. CGraphicsDevice The abstract base class for all graphics devices that represents the medium being drawn to. Manufactures a graphics context suitable for drawing to itself (using CreateContext()), which takes into account the attributes of the device, such as the size and display mode. Allocates (and releases) fonts suitable for drawing to itself and converts between twips and pixels. Important graphic devices are CScreenDevice, CBitmapDevice and CPrinterDevice. (Bitmap applications are discussed later in the chapter.) TZoomFactor Defines a zoom factor and implements the MGraphicsDeviceMap interface. Allocates and releases device-dependent fonts and converts between twips and pixels. Facilitates zooming, because it allows the size of the graphic to become independent of the target size.This class is recursive, because a TZoomFactor object can use an MGraphicsDeviceMap, which could be a TZoomFactor itself, as illustrated below. This allows a zoom factor object to
Class Description Figure 15.3 contain another zoom factor object, multiplying the effect of the child zoom factor. The top-level zoom factor, however, uses a CGraphicsDevice (not another TZoomFactor). In the example, the zoom factor uses the screen device. This is set up as follows in the hello control constructor: iZoomFactor.SetGraphicsDeviceMap(iCoeEnv->ScreenDevice()); iZoomFactor is used for getting the appropriate size and device- dependent font and size for drawing. The following section studies the device-independent drawing code in the CExampleHelloView class and the small amount of deviceindependent code for allocating a font in the CExampleHelloControl class. In the next section, we'll see how the drawing code is used by the CExampleHelloControl class. 15.1.1 Device-independent Drawing Device-independent drawing is largely conducted by the CExample-HelloView class. Here is its declaration: class CExampleHelloView : public CBase { public: // Construct/destruct static CExampleHelloView* NewL(); ~CExampleHelloView(); // Settings void SetTextL(const TDesC& aText); void SetFullRedraw(TBool aFullRedraw); // Draw
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Table of Contents Symbian OS C++ fo
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Reprinted August 2003 All Rights Re
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� consultants, trainers, and auth
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Symbian OS C++ for Mobile Phones fo
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When you're ready to use the Symbia
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improvement. She has a reputation f
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John works in the partner projects
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If you've never seen Symbian OS bef
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within a particular application. In
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There are a number of other ways in
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programs - namely, to handle and re
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There is no need to trap the call t
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abld build winscw udeb The winscw p
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If you're curious, you might want t
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If your connectivity software does
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Chapter 2: System Structure Overvie
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Figure 2.2 Figure 2.3 Symbian OS OE
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Note Actually, for performance reas
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To be executed, an executable has t
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The kernel itself has two major com
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ROM handling is easy. The ROM consi
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You can control the stack size in a
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industry standard, slightly smaller
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A server also uses its own active o
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In order to minimize any difficulty
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� The top-level project name in t
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Title DLL Source Group Headers Desc
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Chapter 3: C++ and Object Orientati
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The fundamental rule is, use names
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Category Examples Description Const
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3.2.6 Summary Naming conventions ar
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Convenience functions are trivial w
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� When declaring a virtual functi
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used in preference to old style C c
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Java uses interfaces too: in Java,
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� Whether these are private or pu
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If the cardinality is not 1-to-1, t
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Figure 4.1 At the bottom is the GDI
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In addition to the four C++ classes
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In addition, as indicated by the SO
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Figure 4.3 SDK and then browse to t
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eturn KErrNone; } Important You mus
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private: // from CEikDocument CEikA
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ConstructL() performs second-phase
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hellogui's application view is a co
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The other things we haven't seen in
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form described above advertises the
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} RESOURCE TBUF r_hellogui_text_hel
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CQikAppUi::HandleWsEventL(const TWs
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4.9 Terminating the Application By
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debug stepping, variable watching,
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5.1 Strings and Memory To understan
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� HBufC* is a pointer to a heap-b
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strlen() doesn't include the traili
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The Des() function returns a TPtr c
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TBuf helloWorld(_L("hello")); greet
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TDes& parameters. Symbian OS itself
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5.4 More Text APIs Symbian OS uses
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encodings of Unicode that use seque
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Chapter 6: Error Handling and Clean
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Even user input errors can be handl
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Note It also demonstrates that the
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eak; So, the New 1 menu item alloca
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this line yourself, and then rerun
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case EMagicCmdNew2: delete iObject2
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If the new(ELeave) fails, then iObj
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If you're writing a function, and t
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} You can invoke these functions fr
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Any one of the calls to UseL() may
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case EMagicCmdUse4: { CY* y = new(E
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� Functions that can leave must o
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CZ::NewL() was actually coded waste
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TAny*. The cleanup code will deallo
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successfully). This means you have
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User::Leave(KErrNone). This appears
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systems outside my control, and res
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Chapter 7: Resource Files Overview
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Data Type Description BUF A Unicode
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} MENU_ITEM { command = EExampleCmd
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A single resource file supports 409
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Filename Description EeikCmdExit, a
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RESOURCE MENU_PANE r_hellogui_hello
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0E [uncompressed data run length] 0
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Chapter 8: Basic APIs Overview We'v
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IMPORT_C void Write(TInt aPos, cons
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_LIT8(KTxt2," world"); buf->InsertL
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Dynamic buffers are also used to st
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Class name Description [*] CArrayFi
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In v7.0, the structure of ROM image
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} In a function such as FormatList(
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library. The next few pages should
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Using this technique, your program
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� The original program consisted
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pointer, and no method of directly
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Figure 9.1 It's a pretty Spartan di
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Note 9.2.3 The Controller As descri
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TInt iLength; // Length - determine
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void SetHit(TInt aX, TInt aY); // H
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The functions to do this are Functi
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User::After(1) is guaranteed to wai
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{ public: // Construct/destruct/set
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This begins by creating a new windo
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); aRect.iTl.iX+iBorderSize+i*iTile
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else gc.SetPenColor(KRgbYellow); gc
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control framework needs to know whe
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the board. It then uses these coord
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Calculate board size in twips, and
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iRightBorder.Move(offset); iBoardRe
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private: // Construct/restore void
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ViewCmdHitFleet() shows how the con
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There are no surprises in the comma
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}; MENU_ITEM {command=EEikCmdZoomIn
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The framework handles creating a fi
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void TShip::ExternalizeL(RWriteStre
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void CGameAppUi::HandleCommandL(TIn
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the target view. Because such messa
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TInt iCursorX; TInt iCursorY; TUid
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display area) and to handle a parti
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Create and load a bitmap iHideBitma
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This version formats the message ID
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Chapter 10: Dialogs and Concrete Co
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Figure 10.2 I got this by typing Ct
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Finally, note that buttons can't be
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for 'control'. I'll always use 'con
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CEikDialog* dialog = new(ELeave) CE
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Simply put, the dialog has a title,
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OK is handled by OkToExitL(). In fa
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Any of the checks or file operation
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}; id = EGameControlIdProtocol; con
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Listen"; } type = EEikCtChoiceList;
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TUid protocol = TUid::Uid(choicelis
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10.3.2 Adding Buttons If you want t
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Function Description virtual void S
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� specify initialization data for
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CEikBorderedControl CEikBorderedCon
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� eikon.rh and Qikon.rh contain t
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Class Header ID CEikGlobalTextEdito
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UIs provide many other standard dia
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Figure 11.1 As it happens, this scr
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gc.DrawText(*iHelloWorld, rect, bas
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The two points that define Trect ca
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The clipping region defines the reg
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virtual void DrawBitmap(const TRect
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Figure 11.5 From the diagram: � T
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In theory, then, you don't need to
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So far, we have suggested that you
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DrawBorders(); DrawTiles(); } but t
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It turns out that working out exact
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Now it's time to be precise about h
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Figure 11.10 It has a single window
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{ public: . . . static CExampleHell
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case 2: return EAmountOfControls; }
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finished. When the BeginRedraw()fun
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Default settings are assured here:
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First and foremost, a control is a
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class CCoeControl : public CBase {
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You can set a control's position an
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IMPORT_C virtual void Draw(const TR
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� If you select OK on a dialog -
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In this chapter, I've concentrated
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TKeyResponse COppFleetView::OfferKe
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TEventCode is the type of window se
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notification, and changing the curs
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From the preceding discussion, it s
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� if the Set interval button is s
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� The general-purpose control des
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private: ... MCoeControlObserver* i
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Special-purpose events should be ha
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Figure 12.4 Key events are offered
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A control should change its appeara
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12.4.3 Grabbing the Pointer-down Co
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ProcessPointerEventL() implements t
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In the last chapter, we concentrate
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making them lighter or darker. For
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Chapter 13: Files, Streams, and Sto
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Note Strictly, documents are not th
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Figure 13.2 The file server provide
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� changing directory and file att
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important in Symbian OS, so it's pr
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Figure 13.5: � Write file allows
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TryChangeFocusToL(EExampleControlId
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file.Close(); // Finished with user
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Page 367 and 368: } // Finish CleanupStack::PopAndDes
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Page 371 and 372: RwriteStream Functions RReadStream
Page 373 and 374: You'll remember that I used this, w
Page 375 and 376: Technique Application descriptor wh
Page 377 and 378: Let's consider the file format of t
Page 379 and 380: � create, write, and close the ap
Page 381 and 382: Figure 13.10 The main document is a
Page 383 and 384: through the DBMS. For more on using
Page 385 and 386: Figure 13.13 There is a small class
Page 387 and 388: � Where an application's .ini fil
Page 389 and 390: The first step of the process is to
Page 391 and 392: END SOURCE 1 icon2mask.bmp SOURCE c
Page 393 and 394: id=EHelloGuiCmd0; flags=EEikToolBar
Page 395 and 396: Figure 14.4 abld build winscw udeb
Page 397 and 398: For the purpose of this book, we'll
Page 399 and 400: #include RESOURCE AIF_DATA { capti
Page 401 and 402: 1 file(s) copied. When this has fin
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Page 405 and 406: The body of this file should be obv
Page 407 and 408: Don't expect the installed applicat
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Page 411 and 412: � Use bold style for active text
Page 413 and 414: Overview This chapter discusses wri
Page 415: Class Description CExampleApplicati
Page 419 and 420: aDeviceRect.Center().iY - boxInPixe
Page 421 and 422: } fontSpec)); The key function here
Page 423 and 424: The second case will cause problems
Page 425 and 426: I'm careful to draw every pixel: I
Page 427 and 428: SetZoomOutL() works the other way r
Page 429 and 430: ealistic print code would take acco
Page 431 and 432: Figure 15.7 The base class for bitm
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Page 435 and 436: #define KRgbYellow TRgb(0x00ffff) #
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Page 439 and 440: Figure 15.8 The GUI used in the Psi
Page 441 and 442: In terms of applications, the appli
Page 443 and 444: Overview So far in this book, we've
Page 445 and 446: Figure 16.2 The starting point for
Page 447 and 448: if (iController->Engine().IsMyTurn(
Page 449 and 450: device, I will have to publish thes
Page 451 and 452: � If your request didn't get thro
Page 453 and 454: Communications is full of this kind
Page 455 and 456: The game will connect and you can s
Page 457 and 458: Figure 16.9 The controller contains
Page 459 and 460: iEngine->iOppFleet.SetShipType(aX,
Page 461 and 462: if(!iController->IsMyTurn()) iEikon
Page 463 and 464: Of course, the opponent's response
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fleet.SetHit(x,y); // update view i
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With this scheme, each chat message
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For a minimum level of skill, the c
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CONE maintains an outstanding reque
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Figure 17.2 It is also worth mentio
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some function that will later gener
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So the scheduler handles precisely
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CActive implements the Cancel() fun
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A RunL() function can stop the acti
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}; Figure 17.9 Member functions her
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Function Description Stop() Decreas
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17.3.1 Maintaining an Outstanding R
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Change visibility of app view text
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static CMultiPartHello* NewL(CActiv
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iTimer.After(iStatus, iDelay); SetA
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I prefer to hide active objects fro
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In active objects, higher priority
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Figure 18.1 Some simple server tran
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A new session has a handle that is
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Figure 18.4 Before any subsessions
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Figure 18.5 When the buffer is full
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Related servers can be run in the s
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� Request the window server to dr
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This is because, when a client thre
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Figure 18.8 18.4.1 Thread Basics Th
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GetDesLength() return this as their
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class RSessionBase : public RHandle
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RSubSessionBase - client-side sub-s
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Bootstrap code for a server should
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The CSharableSession class provides
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RMessage is not intended for deriva
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The GSDP server presented here has
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IMPORT_C TInt GetGdpProtocolInfo(TI
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with all four slots, even if you do
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}; RGsdpSession::Listen() calls CGs
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inline RGsdpSession() : iHandler(0)
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If, in the first step above, the ke
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The GSDP client API implements a sy
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� Function() gives me the request
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Basically, the setter stores its ar
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As we saw in Chapter 17, any API pr
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Many Symbian OS servers use polymor
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construct shutdown timer iShutdown=
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void CGsdpProtocolUpdater::RunL() {
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GSDP clients can select the protoco
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} }; } }; } version_no = 1; display
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} aFromPort, aData); If iLastError
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� The datagram arrives via a GDP
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AddPacket() is a method provided by
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iReceiveMessage.Complete(KErrNone);
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� The client program launches a n
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server.Close(); return died.Int();
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CGsdpScheduler::TServerStart start;
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aStart.SignalL(); CActiveScheduler:
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19.4 Summary In this chapter, we've
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Figure 20.1 Typically, a communicat
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This encapsulation is important, as
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else // Everything was OK, leave th
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suite of protocols: UDP, TCP, ICMP
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member of the GDP-SMS session objec
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This puts it into an initial state,
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void CGdpSmsSender::TSendMsgState::
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If, for some reason, the operation
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RSmsSocketReadStream readstream(iRe
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Bluetooth is composed of a hierarch
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Figure 20.10 shows two sequential o
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As with GDP-SMS, the SendL() functi
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Once connected, the sockets interfa
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err = iListenSocket.Listen(4); User
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iReceiver.iReadSocket.Read(iReceive
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Appendix 1: Example Projects Overvi
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AppForge development software integ
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Psion has a long history of using S
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Appendix 3: TOGS Guide and Referenc
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protected: TUid iDtor_ID_Key; }; CG
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eturn KErrNone; } TInt CGdpLoopback
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packet to the initiating partner: t
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inline RGsdpSession() : iHandler(0)
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Function Description MGsdpPacketHan
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RGCP TOGS is designed to support tu
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Packet structure RGCP uses GSDP as
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State Meaning responses are handled
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Figure A3.10 Here's CRgcpSession's
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void GsdpHandleL(const TDesC8& aDat
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virtual void RgcpHandleBound() = 0;
Page 637 and 638:
State Meaning Listening You have ch
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From To Occurs When other player, t
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Opcode Name Details want-second.Res
Page 643 and 644:
Appendix 4: Emulator Reference Over
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Figure A4.2 This source compatibili
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Figure A4.5 An emulator configurati
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Each Symbian OS .exe built for the
Page 651 and 652:
In different UIs, there can be addi
Page 653 and 654:
ARM data alignment rules are strict
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Key Description W Dump full window
Page 657 and 658:
event handling threads 569 events,
Page 659 and 660:
Application Programming Interfaces
Page 661 and 662:
Boolean data type 55 Boss Puzzle di
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CGsdpSession 650 CanReceivePacket()
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certificate file 472 Certificate Ge
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ServiceL error handling 646 CGsdpSe
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CObjectIx class 614 CodeWarrior deb
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context switching 27 performance is
Page 673 and 674:
CSession class 598, 614, 624 CShara
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text 501 fonts 495 GDI 507 line dra
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const rule, breaking 334 descriptio
Page 679 and 680:
DrawVerticalBorder() function 238 D
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ExternalizeL() function 261 testing
Page 683 and 684:
files 416 copying to emulator 773 s
Page 685 and 686:
G game datagram protocol see GDP pr
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drawing 237 zooming 245 GetZoom() f
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graphics interaction 370 pick corre
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Install() function CActiveScheduler
Page 693 and 694:
graphics interaction handling 370 O
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summary 485 MakeVisible() function
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multithreading 43 MVC 287 controlle
Page 699 and 700:
packets see datagrams palettes 516
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private key 472 privilege boundarie
Page 703 and 704:
ReceiveAllL() 697 ReceivePacket() f
Page 705 and 706:
Revo 23 RFCOMM 701 RFile class 46 v
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RWriteStream 425 streams 430 vs. RF
Page 709 and 710:
CGraphicsContext class 324 SetBrush
Page 711 and 712:
simple getter functions 60 single-p
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Static() function CCoeEnv class 357
Page 715 and 716:
ESOCK sockets server 526 ETEL telep
Page 717 and 718:
TDisplayMode 516 Telephony server 6
Page 719 and 720:
TParsePtr 418 TParsePtrC 418 TPckg
Page 721 and 722:
derivation relationships 75 Unicode
Page 723:
flicker-free redraw 354 invalid reg
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