Play Services GCM's technical work principle in the Java class library

Play Services GCM is a message transmission system used on Android devices, which allows developers to send push notifications to users of applications.This article will in -depth analysis of Play Services GCM's technical work principle in the Java class library and provide Java code examples. Before starting, let's learn about the basic principles of Play Services GCM.GCM (Google Cloud Messaging) based on Google -based cloud services, using GCM can send messages to Android devices through Google's server.GCM uses the Google Play service framework on the device to process the distribution of messages, which is why it is called Play Services GCM. Play Services GCM Java class library provides a set of APIs that can be used in applications.Through these APIs, applications can send messages to the GCM server and receive push notifications from the server.The following is a detailed analysis of the technical work principle of Play Services GCM in the Java class library: 1. Configure the Google Play service: First, developers need to add the dependencies of the Google Play service library to the application built.gradle file.You can use the API key provided by Google for identity verification so that the application can communicate with the GCM server. 2. Registration device: When the application runs for the first time, it will use the API in the Play Services GCM Library to register the device.This will send the unique identifier of the device to the GCM server (usually the registered ID of the device). GoogleCloudMessaging gcm = GoogleCloudMessaging.getInstance(context); String registrationId = gcm.register(SENDER_ID); 3. Send message: To send messages to specific devices, applications need to know the registration ID of the device.Using the API of Play Services GCM Library, the application can build a message object and specify the registration ID of the message content and device to be sent. Message message = new Message.Builder() .addData("title", "New Message") .addData("message", "Hello, world!") .build(); Result result = gcm.send(message, registrationId, numRetries); 4. Receive message: On the device, the application needs to implement a BroadcastReceiver receiver to receive a push notification from the GCM server.When the device receives a new message, the receiver will trigger and pass the message to the application processing.The following is the code of a sample receiver: public class MyGcmReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { Bundle extras = intent.getExtras(); if (extras != null && !extras.isEmpty()) { String message = extras.getString("message"); // Process the receiving message } } } By registering the receiver in the AndroidManifest.xml file, you can notify the system to use this receiver to process GCM messages. <receiver android:name=".MyGcmReceiver" /> The above is the basic working principle of Play Services GCM in the Java class library.By using these APIs, applications can communicate with the GCM server, send and receive messages.This allows developers to easily implement the application of the application of the application and enhance the user experience. In summary, Play Services GCM's technical work principle in the Java class library is very simple and clear.Through registered devices, sending messages and receiving messages, applications can use the functions provided by Play Services GCM to implement push notifications.