Sending a notification from a service in Android

问题:

I have a service running, and would like to send a notification. Too bad, the notification object requires a Context, like an Activity, and not a Service.

Do you know any way to by pass that ? I tried to create an Activity for each notification but it seems ugly, and I can't find a way to launch an Activity without any View.

回答1:

Both Activity and Service actually extend Context so you can simply use this as your Context within your Service.

NotificationManager notificationManager =
    (NotificationManager) getSystemService(Service.NOTIFICATION_SERVICE);
Notification notification = new Notification(/* your notification */);
PendingIntent pendingIntent = /* your intent */;
notification.setLatestEventInfo(this, /* your content */, pendingIntent);
notificationManager.notify(/* id */, notification);

回答2:

This type of Notification is deprecated as seen from documents:

@java.lang.Deprecated
public Notification(int icon, java.lang.CharSequence tickerText, long when) { /* compiled code */ }

public Notification(android.os.Parcel parcel) { /* compiled code */ }

@java.lang.Deprecated
public void setLatestEventInfo(android.content.Context context, java.lang.CharSequence contentTitle, java.lang.CharSequence contentText, android.app.PendingIntent contentIntent) { /* compiled code */ }

Better way
You can send a notification like this:

// prepare intent which is triggered if the
// notification is selected

Intent intent = new Intent(this, NotificationReceiver.class);
PendingIntent pIntent = PendingIntent.getActivity(this, 0, intent, 0);

// build notification
// the addAction re-use the same intent to keep the example short
Notification n  = new Notification.Builder(this)
        .setContentTitle("New mail from " + "[e-mail]")
        .setContentText("Subject")
        .setSmallIcon(R.drawable.icon)
        .setContentIntent(pIntent)
        .setAutoCancel(true)
        .addAction(R.drawable.icon, "Call", pIntent)
        .addAction(R.drawable.icon, "More", pIntent)
        .addAction(R.drawable.icon, "And more", pIntent).build();


NotificationManager notificationManager = 
  (NotificationManager) getSystemService(NOTIFICATION_SERVICE);

notificationManager.notify(0, n); 

Best way
Code above needs minimum API level 11 (Android 3.0).
If your minimum API level is lower than 11, you should you use support library's NotificationCompat class like this.

So if your minimum target API level is 4+ (Android 1.6+) use this:

    import android.support.v4.app.NotificationCompat;
    -------------
    NotificationCompat.Builder builder =
            new NotificationCompat.Builder(this)
                    .setSmallIcon(R.drawable.mylogo)
                    .setContentTitle("My Notification Title")
                    .setContentText("Something interesting happened");
    int NOTIFICATION_ID = 12345;

    Intent targetIntent = new Intent(this, MyFavoriteActivity.class);
    PendingIntent contentIntent = PendingIntent.getActivity(this, 0, targetIntent, PendingIntent.FLAG_UPDATE_CURRENT);
    builder.setContentIntent(contentIntent);
    NotificationManager nManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    nManager.notify(NOTIFICATION_ID, builder.build());

回答3:

@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
public void PushNotification()
{
    NotificationManager nm = (NotificationManager)context.getSystemService(NOTIFICATION_SERVICE);
    Notification.Builder builder = new Notification.Builder(context);
    Intent notificationIntent = new Intent(context, MainActivity.class);
    PendingIntent contentIntent = PendingIntent.getActivity(context,0,notificationIntent,0);

    //set
    builder.setContentIntent(contentIntent);
    builder.setSmallIcon(R.drawable.cal_icon);
    builder.setContentText("Contents");
    builder.setContentTitle("title");
    builder.setAutoCancel(true);
    builder.setDefaults(Notification.DEFAULT_ALL);

    Notification notification = builder.build();
    nm.notify((int)System.currentTimeMillis(),notification);
}

回答4:

Well, I'm not sure if my solution is best practice. Using the NotificationBuilder my code looks like that:

private void showNotification() {
    Intent notificationIntent = new Intent(this, MainActivity.class);

    PendingIntent contentIntent = PendingIntent.getActivity(
                this, 0, notificationIntent, PendingIntent.FLAG_UPDATE_CURRENT);
    builder.setContentIntent(contentIntent);
    NotificationManager notificationManager =
            (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    notificationManager.notify(NOTIFICATION_ID, builder.build());
    }

Manifest:

    <activity
        android:name=".MainActivity"
        android:launchMode="singleInstance"
    </activity>

and here the Service:

    <service
        android:name=".services.ProtectionService"
        android:launchMode="singleTask">
    </service>

I don't know if there really is a singleTask at Service but this works properly at my application...

回答5:

If none of these work, try getBaseContext(), instead of context or this.