How does the Android socket work?

In Android, Socket is a network communication protocol that operates based on the TCP/IP protocol stack.

Specifically, in Android, sockets are implemented using the Transmission Control Protocol (TCP). TCP is a reliable communication protocol that establishes a connection between a client and server to ensure the reliable transmission of data. In Android, the Socket class provides a simple yet powerful way to implement TCP/IP network communication.

The working principle of sockets in Android is as follows:

1. Establishing a connection: The client creates a Socket object using the Socket class and specifies the IP address and port number of the server. Next, the client establishes a connection with the server by calling the connect() method.
2. Data transmission: Once the connection is established, data can be transferred between the client and server using input and output streams. The client sends data to the server through the output stream of the Socket, and the server receives data through the input stream of the Socket.
3. Data processing: Clients and servers have the ability to handle the received data according to their own needs, such as converting data into strings, parsing into JSON objects, etc.
4. Disconnect: When communication is finished, the client and server can each call the close() method of the Socket to end the connection.

It is important to note that socket communication in Android is based on a blocking IO model, which means that the program will be blocked when conducting network communication until data transmission is completed or an error occurs. To avoid blocking the main thread, socket communication is usually done in a separate thread. Additionally, Android also provides a non-blocking socket communication method, which can be implemented using Java’s NIO (New Input/Output) library.