Question

我正在尝试推送通知应用。我一直关注Ravi Tamada的博客http://www.androidhive.info/2012/10/android-push-notifications-using-google-cloud-messaging-gcm-php-and-mysql/我不明白其中一个班级的流程。

课程如下..

 public class InitialActivity extends Activity {
// label to display gcm messages
TextView lblMessage;

// Asyntask
AsyncTask<Void, Void, Void> mRegisterTask;

// Alert dialog manager
AlertDialogManager alert = new AlertDialogManager();

// Connection detector
ConnectionDetector cd;

public static String name;
public static String email;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main_pn);

    cd = new ConnectionDetector(getApplicationContext());

    // Check if Internet present
    if (!cd.isConnectingToInternet()) {
        // Internet Connection is not present
        alert.showAlertDialog(InitialActivity.this,
                "Internet Connection Error",
                "Please connect to working Internet connection", false);
        // stop executing code by return
        return;
    }

    // Getting name, email from intent
    Intent i = getIntent();

    name = i.getStringExtra("name");
    email = i.getStringExtra("email");      

    // Make sure the device has the proper dependencies.
    GCMRegistrar.checkDevice(this);

    // Make sure the manifest was properly set - comment out this line
    // while developing the app, then uncomment it when it's ready.
    GCMRegistrar.checkManifest(this);

    lblMessage = (TextView) findViewById(R.id.lblMessage);

    registerReceiver(mHandleMessageReceiver, new IntentFilter(
            DISPLAY_MESSAGE_ACTION));

    // Get GCM registration id
    final String regId = GCMRegistrar.getRegistrationId(this);

    // Check if regid already presents
    if (regId.equals("")) {
        // Registration is not present, register now with GCM   
        lblMessage.append("inside first if condition where regid = null" + "\n\n"); 
        GCMRegistrar.register(this, SENDER_ID);
    } else {
        // Device is already registered on GCM
        if (GCMRegistrar.isRegisteredOnServer(this)) {
            // Skips registration.              
            Toast.makeText(getApplicationContext(), "Already registered with GCM", Toast.LENGTH_LONG).show();
        } else {
            // Try to register again, but not in the UI thread.
            // It's also necessary to cancel the thread onDestroy(),
            // hence the use of AsyncTask instead of a raw thread.
            lblMessage.append("inside 2nd if condition where regid != null and GCMRegistrar.isRegisteredOnServer(this) = false " + "\n");   
            final Context context = this;
            mRegisterTask = new AsyncTask<Void, Void, Void>() {

                @Override
                protected Void doInBackground(Void... params) {
                    // Register on our server
                    // On server creates a new user
                    lblMessage.append("inside doinbackground" + "\n\n");
                    ServerUtilities.register(context, name, email, regId);
                    return null;
                }

                @Override
                protected void onPostExecute(Void result) {
                    mRegisterTask = null;
                }

            };
            mRegisterTask.execute(null, null, null);
        }
    }
}       

/**
 * Receiving push messages
 * */
private final BroadcastReceiver mHandleMessageReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        lblMessage.append("inside BroadcastReceiver mHandleMessageReceiver " + "\n\n"); 
        String newMessage = intent.getExtras().getString(EXTRA_MESSAGE);
        // Waking up mobile if it is sleeping
        WakeLocker.acquire(getApplicationContext());

        /**
         * Take appropriate action on this message
         * depending upon your app requirement
         * For now i am just displaying it on the screen
         * */

        // Showing received message
        lblMessage.append(newMessage + "\n\n");         
        Toast.makeText(getApplicationContext(), "New Message: " + newMessage, Toast.LENGTH_LONG).show();
        // From Demo Server: successfully added device!
        // Releasing wake lock
        WakeLocker.release();
    }
};

@Override
protected void onDestroy() {
    if (mRegisterTask != null) {
        mRegisterTask.cancel(true);
    }
    try {
        lblMessage.append("onDestroy " + "\n"); 
        unregisterReceiver(mHandleMessageReceiver);
        GCMRegistrar.onDestroy(this);
    } catch (Exception e) {
        Log.e("UnRegister Receiver Error", "> " + e.getMessage());
    }
    super.onDestroy();
}

}

现在它的输出如下..

程序进入广播接收机3次..这是怎么发生的？我将相同的代码应用到另一个应用程序，但代码只进入广播接收器一次..所以发生了什么？

Answer 1

评论说明了一切。查看开头的代码，您将检查互联网连接。第二，一旦检查，您将注册接收器以接收GCM消息。首先，您将尝试从GCM服务器获取设备的注册ID。如果没有注册（您将获得＆＃34;＆＃34;），请尝试在GCM服务器中注册您的设备，这对于获取GCM消息非常重要。一旦注册了该应用项目（您无法获得任何ID），请尝试在您的服务器中注册，因为您的服务器需要具有您移动设备的唯一注册ID才能发送GCM消息。 Receiver将接收来自GCM的消息。这就是整个代码所说的。对于分步代码，抱歉。你至少需要付出一些努力。

试图了解程序的流程

1 个答案: