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For protocols such as Bluetooth, which are fast and free, this is too heavyweight. It produces the oddity that, when playing Battleships over Bluetooth, you don't see a response to your move until the other player has decided what move to take. That's OK over SMS, but over Bluetooth it feels odd. It would be possible to add either another layer, or a fairly compatible modification, to RGCP: � This could allow responses to be sent immediately, without waiting for a piggyback packet. � Given the possibility of an immediate response, requires an immediate response in some situations and, if one does not arrive, resend automatically. I have provisionally called this protocol QRGCP (Q = quick), but haven't implemented it. CRgcpSession could use better construction encapsulation. Rather than providing a C++ constructor to be followed by either ConstructL()or RestoreL(), it would be better to provide two public NewL()s, one with construct semantics and the other with restore semantics. The Battleships Protocol BSP, the Battleships Protocol, builds on RGCP to allow players to play the two-player game. Within the span of a single conversation (or 'session'), multiple Battleships games may be played. Outside a session, you cannot play a game. A session is set up by one partner initiating and the other listening. Partners specify whether they want to move first, or move second, or don't care. The decision is arbitrated in favor of the initiating partner (who will go first if they so requested, or if neither party cares, or if the other partner asked to go second). Normal play consists of a sequence of move requests. The game may be finished by being won by one partner (and therefore lost by the other) or by being abandoned by the player whose turn it is to move. If the game is finished in either of these ways, the session remains active and another game can be started. This time, the player who lost or abandoned gets preference for the first move. The RGCP session may be terminated, at any time, which of course terminates any game currently in progress. Protocol Overview Here's a brief look at the details of BSP. States The possible states of a Battleships application are State Meaning Blank No conversation is established. The game is in an arbitrary state (either a neutral state if the program has just started, or the state at the end of the last game if a conversation has been terminated). Initiating You have chosen whom to play against and initiated a conversation with them. You have also specified your first-move preferences. The game is initialized to a neutral position.
State Meaning Listening You have chosen to play and are waiting to accept a conversation initiated by someone else. You have also specified your first-move preferences. The game is initialized to a neutral position. Starting You are bound in a session and have sent a start request to the other player specifying your first-move preferences. The game is initialized in a neutral position. Accepting You are bound in a session and are expecting to receive a start request from the other player. You have specified your first-move preferences and the game is in a neutral position. My-turn A game is in progress, and it's your turn to move. Opp-turn A game is in progress, and it's your opponent's turn to move. Finished The game has been won, lost, or abandoned (which amounts to substates of finished). Restarting You are going to restart the game, but you don't yet have your first-move preferences. State transitions The transitions in Figure A3.11 are described in more detail below: Figure A3.11 From To Occurs When Blank Initiating Player specifies first-move preferences and the address of player to connect to. An RGCP initiate-
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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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Update view iAppView->DrawNow(); }
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} // Finish CleanupStack::PopAndDes
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external stream and de-serialize wh
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RwriteStream Functions RReadStream
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You'll remember that I used this, w
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Technique Application descriptor wh
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Let's consider the file format of t
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� create, write, and close the ap
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Figure 13.10 The main document is a
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through the DBMS. For more on using
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Figure 13.13 There is a small class
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� Where an application's .ini fil
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The first step of the process is to
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END SOURCE 1 icon2mask.bmp SOURCE c
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id=EHelloGuiCmd0; flags=EEikToolBar
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Figure 14.4 abld build winscw udeb
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For the purpose of this book, we'll
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#include RESOURCE AIF_DATA { capti
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1 file(s) copied. When this has fin
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The way the Certificate Generator w
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The body of this file should be obv
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Don't expect the installed applicat
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� Every application should fill t
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� Use bold style for active text
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Overview This chapter discusses wri
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Class Description CExampleApplicati
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Class Description Figure 15.3 conta
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aDeviceRect.Center().iY - boxInPixe
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} fontSpec)); The key function here
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The second case will cause problems
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I'm careful to draw every pixel: I
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SetZoomOutL() works the other way r
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ealistic print code would take acco
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Figure 15.7 The base class for bitm
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lit them efficiently from a shared
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#define KRgbYellow TRgb(0x00ffff) #
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world colors mapped down onto black
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Figure 15.8 The GUI used in the Psi
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In terms of applications, the appli
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Overview So far in this book, we've
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Figure 16.2 The starting point for
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if (iController->Engine().IsMyTurn(
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device, I will have to publish thes
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� If your request didn't get thro
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Communications is full of this kind
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The game will connect and you can s
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Figure 16.9 The controller contains
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iEngine->iOppFleet.SetShipType(aX,
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if(!iController->IsMyTurn()) iEikon
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Of course, the opponent's response
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wrong with it. And it may not alway
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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
Page 585 and 586: member of the GDP-SMS session objec
Page 587 and 588: This puts it into an initial state,
Page 589 and 590: void CGdpSmsSender::TSendMsgState::
Page 591 and 592: If, for some reason, the operation
Page 593 and 594: RSmsSocketReadStream readstream(iRe
Page 595 and 596: Bluetooth is composed of a hierarch
Page 597 and 598: Figure 20.10 shows two sequential o
Page 599 and 600: As with GDP-SMS, the SendL() functi
Page 601 and 602: Once connected, the sockets interfa
Page 603 and 604: err = iListenSocket.Listen(4); User
Page 605 and 606: iReceiver.iReadSocket.Read(iReceive
Page 607 and 608: Appendix 1: Example Projects Overvi
Page 609 and 610: AppForge development software integ
Page 611 and 612: Psion has a long history of using S
Page 613 and 614: Appendix 3: TOGS Guide and Referenc
Page 615 and 616: protected: TUid iDtor_ID_Key; }; CG
Page 617 and 618: eturn KErrNone; } TInt CGdpLoopback
Page 619 and 620: packet to the initiating partner: t
Page 621 and 622: inline RGsdpSession() : iHandler(0)
Page 623 and 624: Function Description MGsdpPacketHan
Page 625 and 626: RGCP TOGS is designed to support tu
Page 627 and 628: Packet structure RGCP uses GSDP as
Page 629 and 630: State Meaning responses are handled
Page 631 and 632: Figure A3.10 Here's CRgcpSession's
Page 633 and 634: void GsdpHandleL(const TDesC8& aDat
Page 635: virtual void RgcpHandleBound() = 0;
Page 639 and 640: From To Occurs When other player, t
Page 641 and 642: Opcode Name Details want-second.Res
Page 643 and 644: Appendix 4: Emulator Reference Over
Page 645 and 646: Figure A4.2 This source compatibili
Page 647 and 648: Figure A4.5 An emulator configurati
Page 649 and 650: 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
Page 655 and 656: 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
Page 663 and 664: CGsdpSession 650 CanReceivePacket()
Page 665 and 666: certificate file 472 Certificate Ge
Page 667 and 668: ServiceL error handling 646 CGsdpSe
Page 669 and 670: CObjectIx class 614 CodeWarrior deb
Page 671 and 672: context switching 27 performance is
Page 673 and 674: CSession class 598, 614, 624 CShara
Page 675 and 676: text 501 fonts 495 GDI 507 line dra
Page 677 and 678: const rule, breaking 334 descriptio
Page 679 and 680: DrawVerticalBorder() function 238 D
Page 681 and 682: 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
Page 687 and 688:
drawing 237 zooming 245 GetZoom() f
Page 689 and 690:
graphics interaction 370 pick corre
Page 691 and 692:
Install() function CActiveScheduler
Page 693 and 694:
graphics interaction handling 370 O
Page 695 and 696:
summary 485 MakeVisible() function
Page 697 and 698:
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
Page 707 and 708:
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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