Retrieving currently active access point（转）

ID	TSS000467	Creation date	November 22, 2006
Platform	S60 2nd Edition, S60 2nd Edition FP1, FP2, and FP3 S60 3rd Edition, S60 3rd Edition FP1	Devices
Category	Symbian C++	Subcategory

Keywords (APIs, classes, methods, functions):

Overview

Retrieving currently active access point

Description

There are several instances where the system will prompt the user with an access point selection dialog. For example,    - Initiating an HTTP connection
    - Downloading a file with Download Manager API
    - Opening a URL in Browser Control API
It is possible to reuse the active access point. A common use case would be opening an HTTP connection and starting a file download with Download Manager API. Reusing the access point prevents the AP selection dialog from being shown twice.

Solution

MConnectionMonitorObserver is an observer class that is provided to receive any event notifications like creation or deletion of a connection, IAP availability change etc. The client application must implement this interface in order to receive notifications.The steps involved are:
1) Derive the MConnectionMonitorObserver mixin class and implement the callback function EventL():

class CMyHTTPEngine : public MConnectionMonitorObserver
    {
    ...
 public:
    // from MConnectionObserver
    void EventL(const CConMonEvenBase& aConnEvent);
    ...
 private:
    RConnectionMonitor iConnMon;
    };
2) Register to get notifications on events before allowing the user to make an HTTP connection
    TInt err = iConnMon.ConnectL();
    iConnMon.NotifyEventL( *this );
    // … proceed to open HTTP connection

3) Handle received events and detect the ID of the active IAP
 CMyHTTPEngine::EventL(const CConMonEvenBase& aConnEvent)
    {
    TInt event = aConnEvent.EventType();
    TUint connId = aConnEvent.ConnectionId();  
    TUint iapId;
    TRequestStatus status;
     switch ( event )
        {
        case EConnMonCreateConnection: // New connection created
            {
            // Cast aConnEvent to CConnMonCreateConnection if needed
            iConnMon.GetUintAttribute(connId, 0, KIAPId, iapId, status);
       
            // Name of AP can be retrieved with
            // GetStringAttribute(connId, 0, KIAPName, ...)
            User::WaitForRequest( status );
            break;
            }
        case EConnMonCreateSubConnection: // Subconnection to an existing AP
            {
            TUint subConnId;
            // Cast aConnEvent to CConnMonCreateSubConnection if needed       
            const CConnMonCreateSubConnection
                subConnEvent = (CConnMonCreateSubConnection)aConnEvent;
            subConnId = subConnEvent.SubConnectionId();
            iConnMon.GetUintAttribute(connId, subConnId, KIAPId, iapId, status);
            // Name of AP can be retrieved with
            // GetStringAttribute(connId, subConnId, KIAPName, ...)
            User::WaitForRequest( status );
            break;
            }
        default:
            break;
        }
    // Close the monitor when event notifications are no longer required
    // iConnMon.Close();
    }
The observer can also be used for notifications on events like change in accessibility of an access point, deletion of an existing connection and changes in connection status.