Play Services GCM Technical Principles Analysis

Play Services GCM Technical Principles Analysis Play Services GCM (Google Cloud Messaging) is a cloud push service provided by Google, which allows developers to send messages and notifications to Android devices.This article will analyze Play Services GCM technical principles and provide Java code examples. 1. What is Play Services GCM? Play Services GCM is a cloud -based message transmission framework. Through the services provided by Google, a message push between the server and Android devices.It allows developers to send messages and notifications to devices registered with GCM services in order to interact with users in real time. 2. Play Services GCM working principle 1. Register GCM service On Android devices, developers need to use Google Play service SDK to register GCM service.After registration, the device will get a unique identifier (that is, register token) to send messages on the server. 2. Send a message to the GCM server Developers need to send the message to the GCM server.The message can be a combination of notifications, data or two.Each message contains a registered token of a target device. 3. The GCM server puts the message route to the target device After the GCM server receives the message, the message routing to the target device.After the device receives the message, it can customize the processing logic, such as displaying notifications or executing specific operations. 4. Send confirmation information to the GCM server After the device receives the message, send confirmation information to the GCM server.In this way, the GCM server knows that the news has been successfully delivered. 5. Optional ACK (Answe) message If the developer wants to pass the two -way message with the server, it can be implemented by sending ACK messages to the GCM server.ACK message carries custom data and sends it to the target device. 3. Java code example The following is an example of Java code using Play Services GCM: 1. Register GCM service GoogleCloudMessaging gcm = GoogleCloudMessaging.getInstance(context); String registrationToken = gcm.register(SERVER_APP_ID); 2. Send a message to the GCM server JSONObject message = new JSONObject(); message.put("title", "Hello"); message.put("body", "This is a GCM message"); String jsonString = message.toString(); HttpPost httpPost = new HttpPost(GCM_SERVER_URL); httpPost.setHeader("Authorization", "key=" + SERVER_API_KEY); httpPost.setHeader("Content-Type", "application/json"); httpPost.setEntity(new StringEntity(jsonString)); HttpClient client = new DefaultHttpClient(); HttpResponse response = client.execute(httpPost); 3. The processing of the device after receiving the message @Override public void onMessageReceived(String from, Bundle data) { String title = data.getString("title"); String body = data.getString("body"); // Show notification or process other logic } Please note that the above code example is only the basic usage of GCM, not a complete implementation.In practical applications, appropriate error processing and network connection code need to be added. in conclusion Play Services GCM technology uses the cloud push service provided by Google to enable developers to send messages and notifications to Android devices.This article analyzes the working principle of Play Services GCM and provides related Java code examples.I hope this article can help readers better understand and use Play Services GCM.