If you need to use a long connection in development, especially websocket, we usually use Android-webSocket, or okHTTP for links. But of all the options I prefer to use Socketio. The most intuitive feature of Socketio is message classification, which makes message management more convenient. Here I briefly explain how socketio can be used on Android. If you are a server, please find other information to learn.

1. First, we need to introduce the relevant socket. IO development dependencies

Implementation 'IO. Sockets: the socket. IO - client: 1.0.0'Copy the code

2. Next we add network permissions to the project

<uses-permission android:name="android.permission.INTERNET"/>
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3. Next we create the socket. IO link

Creating a Socket object

private Socket mSocket;
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The mSocket is then initialized

try { IO.Options opts = new IO.Options(); opts.query = "loginUserNum=" + 78; MSocket = IO. Socket (" http://192.168.0.162:9099 ", opts); } catch (URISyntaxException e) {e.printStackTrace(); }Copy the code

Opts is an identification received by the background when establishing a link. It identifies which client is establishing a long connection with the background

4. Start linking

mSocket.connect();
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5. Link callback listener successfully

mSocket.on("connect", new Emitter.Listener() { @Override public void call(Object... Args) {runOnUiThread(new Runnable() {@override public void run() {tv_lj.settext (); }}); }});Copy the code

The callbacks here are child threads, so be aware that if you need to change the UI, you must go into the main thread to make the changes.

6. Message receive callback listening

mSocket.on("text", new Emitter.Listener() { @Override public void call(final Object... args) { runOnUiThread(new Runnable() { @Override public void run() { tv_content.setText(args[0].toString()); }}); }});Copy the code

7. Send messages

Msocket. emit("text"," finally sent ");Copy the code

8. Link destruction

Finally, don’t forget to destroy the link

@Override
public void onDestroy() {
    super.onDestroy();
    mSocket.off();
    mSocket.disconnect();
}
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9. Configure the network

Now you find that the connection is still not successful, don’t worry, we need to add a configuration

Create the XML package under res and create network_security_config.xml as follows

<? The XML version = "1.0" encoding = "utf-8"? > <network-security-config> <base-config cleartextTrafficPermitted="true" /> </network-security-config>Copy the code

It is then configured under the Application node in the manifest file, androidmanifest.xml

android:networkSecurityConfig="@xml/network_security_config"
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At this point our socket. IO link is complete. We can use this set of code for autonomous IM instant messaging, heartbeat setup and so on.

Each socket. IO message can be assigned a message type to ensure that we set up multiple socket. IO callbacks to listen for different messages and achieve message classification. At the same time, socket. IO also supports multi-platform access, which can realize the purpose of using a set of framework for multiple platforms.