IdTCPClient on Android: Connecting to non-active network

[rlebeau]

I tried this:
IdTCPClient1.Socket.Binding.SetBinding(NetworkData.LocalIP,APort);

You don't need to call SetBinding() manually, Indy handles the binding for you, using the values of the BoundIP and BoundPort properties.

What function is the Port in this case? Does this have any effect on setting the socket, and if so, what Port am I supposed to use?

It is the local Port that the client binds to before connecting to the remote server. A TCP connection is uniquely identified by the combination of the socket's protocol, client's bound IP/Port, and the server's bound IP/Port.

Then,
SetSockOpt(ALevel: TIdSocketOptionLevel;  AOptName: TIdSocketOption; AOptVal: Integer);

Those are three integers I am supposed to supply. I have no idea what these mean.

Read the Linux man documentation for the setsockopt() function, and the SO_BINDTODEVICE socket option in particular:

https://linux.die.net/man/2/setsockopt

https://linux.die.net/man/7/socket

Also, after hours digging through the Android API (24) help, I cannot find any way to retrieve an integer which I could use to call SetSockOpt() with.

Android runs on top of Linux. Indy accesses Linux's socket APIs directly, it does not use Android's APIs.

Going through the source of Indy, it ends with an GStack.SetSocketOption(Handle, ALevel, AOptName, AOptVal); overload; virtual; abstract;
of which I cannot find the actual source code to see what it does...

On Android, it is implemented in the Lib\System\IdStackVCLPosix.pas source file.

PS: After I assign the "IdTCPClient1.IOHandler := IdSSLIOHandlerSocketOpenSSL1;" , calls to the IdTCPClient1.Socket.Binding.SetBinding will be passed on to IdSSLIOHandlerSocketOpenSSL1 where required?

Yes. Connect() handles that for you.