weatherinfo.cpp

symbian下的几个小例子。。很值得学习

// weatherinfo.cpp
//
// Copyright (c) Symbian Software Ltd 1999 - 2007.  All rights reserved.
//


/*===========================================================================
     This file contains the active object for collecting the weather info
     from the network.

     The sequence of events to collect the temparature is started by the
     GetTemperature() method and issueing the host resolve.  When that is complete
     RunL() is invoked and the next network call in the sequence and is called and so on
     until temperature is retrieved. 
============================================================================*/

#include "weatherinfo.h"

CWeatherInfo* CWeatherInfo::NewL(MWeatherObserver& aObserver)
    {    
    CWeatherInfo* self = new(ELeave) CWeatherInfo(aObserver);
    CActiveScheduler::Add(self);
    return self;
    }

// This isn't a UI object, but is performing background network retrieval so
// doesn't need user input priority...or does it?
CWeatherInfo::CWeatherInfo(MWeatherObserver& aObserver) 
    : CActive(CActive::EPriorityStandard), iObserver(aObserver)
{}


void CWeatherInfo::GetTemperature(const TDesC& aCity)
    {
// if we are already in the middle of getting the temperature, then
// return.
    if (IsActive())
        return;
       
    iCommState=EInitializing;

    TInt res =iSocketSrv.Connect();
    if (res != KErrNone)
        {
        Cleanup(res);  
        return;
        }
   
    iCityCode.Copy(aCity);
/*-------------------------------------------------------------------------------------
   Use the RConnection API to start the network connection if not already started.
------------------------------------------------------------------------------------- */
    res = iConnection.Open(iSocketSrv);
    if (res != KErrNone)
        {
        Cleanup(res);
        return;
        }
    res = iConnection.Start();
    if (res != KErrNone)
        {
        Cleanup(res);
        return;
        }
/*------------------------------------------------------------------------------------
    Open the socket.
------------------------------------------------------------------------------------*/
        iSocket.Open(iSocketSrv,KAfInet,KSockStream,KProtocolInetTcp,iConnection);  
        if (res != KErrNone)
            {
            Cleanup(res); 	  
            return;
            }
      
/* Resolve name, rest handled by RunL() */
 
        res = iResolver.Open(iSocketSrv, KAfInet, KProtocolInetTcp,iConnection);
        if (res != KErrNone)
            {
            Cleanup(res);  
            return;
            }
        iCommState=EResolvingName;
       
        _LIT(KWeatherServerName,"rainmaker.wunderground.com");
        iResolver.GetByName(KWeatherServerName, iNameEntry, iStatus);
        SetActive();       
        }

CWeatherInfo::~CWeatherInfo()
    {
    // Make sure we're cancelled
    Cancel();
    }

void CWeatherInfo::RunL()
    {
    if (iStatus != KErrNone)
        {
        Cleanup(iStatus.Int());  
        }
    else
        {
        switch(iCommState)
            {
            case  EResolvingName:
                {
                TInetAddr destAddr;
                destAddr=iNameEntry().iAddr;
                destAddr.SetPort(3000);

                // Connect to the remote host
                iCommState=EConnecting;
                iSocket.Connect(destAddr,iStatus);
                SetActive();
                break;
                }
            case EConnecting:
                {
                _LIT(KCRLF,"\xD\xA");

                TBuf8<300> getBuff;
                getBuff.Copy(KCRLF);
                getBuff.Append(iCityCode);
                getBuff.Append(KCRLF);
                
                iCommState=ESending;
                iSocket.Send(getBuff,0,iStatus);
                SetActive();
                break;
                }
            case ESending:
                {
              // Start receiving
              
                iCommState=EReceiving;
             
                iSocket.RecvOneOrMore(iNetBuff,0,iStatus,iLen);
                SetActive();
                break;             
                }
           case EReceiving:
                {
/*------------------------------------------------------------------- 
   The rainmaker.wunderground.com line with the temperature starts 
   after a line filled with '='s. 
-------------------------------------------------------------------*/
                _LIT8(KFileTok,"=\xA");
                TInt pos = iNetBuff.FindF(KFileTok);
                TBuf<100> temp;
                if (pos != KErrNotFound)
                    {
                    temp.Copy(iNetBuff.Mid(pos+2,10));
                    temp.Trim();
                    iObserver.TemperatureReport(iCityCode,temp);  
                    Cleanup(KErrNone);
                    } 
                else
                    {                 
                    iSocket.RecvOneOrMore(iNetBuff,0,iStatus,iLen);
                    SetActive();
                    }
                break;
                }  
            default:
                ASSERT(EFalse);	//	Should never get here
            }            
        }
    }

void CWeatherInfo::DoCancel()
    {
    iSocket.CancelAll();
    Cleanup(KErrCancel);
    }

void CWeatherInfo::Cleanup(TInt aError)
    {
    iSocket.Close();
    iResolver.Close();	
    iConnection.Close();
    iSocketSrv.Close();

    TBuf<50> errStr;
    if (aError!=KErrNone)
        {
        switch (iCommState)
            {
            case EInitializing:
                {
                _LIT(KErrStr,"Error initializing communications");
                errStr.Copy(KErrStr);
                break;
                }
            case EResolvingName:
                {
                _LIT(KErrStr,"Error resolving name");
                errStr.Copy(KErrStr);
                break;
                }
            case EConnecting:
                {
                _LIT(KErrStr,"Error connecting to server");
                errStr.Copy(KErrStr);
                break;
                }
            case ESending:
                {
                _LIT(KErrStr,"Error sending request");
                errStr.Copy(KErrStr);
                break;
                }   
            case EReceiving:
                {
                _LIT(KErrStr,"Error receiving data");
                errStr.Copy(KErrStr);
                break;
                }
            default:
                {
                _LIT(KErrStr,"Unknown error");
                errStr.Copy(KErrStr);
                break;
                }
            }
        iObserver.TemperatureError(errStr,aError);
        }
    }