Discuss the technical principles of the Play Services GCM framework in the Java library
Discuss the technical principles of the Play Services GCM framework in the Java library
In mobile application development, Google Play Services GCM (Google Cloud Messaging) framework plays an important role in implementing message transmission and push notifications between mobile devices.The framework uses the Java library to provide the core function of communication, providing developers with a simple and reliable way to send asynchronous messages and real -time notifications.
The technical principles of the Play Services GCM framework mainly revolves around the following core components:
1. GCM registration service: Mobile applications need to register GCM services on the device to receive news from the cloud.Developers are registered by obtaining the device identifier provided by Google.The registered service is responsible for transmitting the logo of the device to the GCM server and stored the returned token on the device for use.
The following example code demonstrates how to register the device through the GCM registration service:
import com.google.android.gms.gcm.GoogleCloudMessaging;
import com.google.android.gms.iid.InstanceID;
public class GCMRegistrationService extends IntentService {
public GCMRegistrationService() {
super("GCMRegistrationService");
}
@Override
protected void onHandleIntent(Intent intent) {
try {
InstanceID instanceID = InstanceID.getInstance(this);
String token = instanceID.getToken(getString(R.string.gcm_defaultSenderId),
GoogleCloudMessaging.INSTANCE_ID_SCOPE, null);
Log.d("GCMRegistrationService", "Registration Token: " + token);
// Send the token to your application server for storage
sendRegistrationToServer(token);
} catch (IOException e) {
e.printStackTrace();
}
}
private void sendRegistrationToServer(String token) {
// Send the token to your server logic
}
}
2. Downstream Messaging: Through the GCM framework, developers can send real -time news to the registered device.Developers need to send the effective load and device logo of the message to the GCM server.Once the GCM server receives the message, it will be responsible for sending the message to the target device.
The following example code demonstrates how to use GCM to send an instant message to the device:
import com.google.android.gms.gcm.GoogleCloudMessaging;
public class GCMSendMessageService extends IntentService {
public GCMSendMessageService() {
super("GCMSendMessageService");
}
@Override
protected void onHandleIntent(Intent intent) {
String deviceId = intent.getStringExtra("DEVICE_ID");
String messagePayload = intent.getStringExtra("MESSAGE_PAYLOAD");
try {
GoogleCloudMessaging gcm = GoogleCloudMessaging.getInstance(this);
gcm.send(getString(R.string.gcm_defaultSenderId) + "@gcm.googleapis.com",
deviceId, System.currentTimeMillis() + 60000, messagePayload, null);
} catch (IOException e) {
e.printStackTrace();
}
}
}
3. GCM push notification (Upstream MESSAGING): In addition to real -time communication, the GCM framework also supports the application server to send push notifications to the device.The application server needs to send the valid load and device logo of the notification to the GCM server.The GCM server will be responsible for passing notifications to the application of the target device.
The following example code demonstrates how to use GCM to send push notifications to the device:
import com.google.android.gms.gcm.GoogleCloudMessaging;
public class GCMSendNotificationService extends IntentService {
public GCMSendNotificationService() {
super("GCMSendNotificationService");
}
@Override
protected void onHandleIntent(Intent intent) {
String deviceId = intent.getStringExtra("DEVICE_ID");
String notificationPayload = intent.getStringExtra("NOTIFICATION_PAYLOAD");
try {
GoogleCloudMessaging gcm = GoogleCloudMessaging.getInstance(this);
gcm.send(getString(R.string.gcm_defaultSenderId) + "@gcm.googleapis.com",
deviceId, System.currentTimeMillis() + 60000,
getNotificationMessage(notificationPayload), null);
} catch (IOException e) {
e.printStackTrace();
}
}
private Bundle getNotificationMessage(String notificationPayload) {
Bundle message = new Bundle();
// Add notification related key values pairs to Bundles
return message;
}
}
In summary, the Play Services GCM framework provides an efficient and reliable message transmission and push notification mechanism through core components such as GCM registration services, GCM instant messaging, and GCM push notifications.Developers can use these functions to build optimized mobile applications.
