How to properly update a notification post api 11?

问题:

• Before Notification.Builder came into existence the way to update a notification that was already in the notification tray was to call setLatestEventInfo() and then send the notification back through the NotificationManager.notify() call with an ID that matches the first notify() call you made.

• Now setLatestEventInfo() is deprecated with the message: Use Notification.Builder instead. But I cannot find any documentation about how to properly update a notification using Notification.Builder.

• Are you just suppose to recreate a new Notification instance every time you need to update the notification? Then simply pass that to NotificationManager.notify() with the ID you used before?

• It seems to work but I wanted to see if anyone had any official verification that this is the new "way to do this"?

There real reason I am asking this is because in Android 4.1.1 Jelly Bean, the notification now flashes everytime notify() is called. When updating a progress bar with setProgress() this looks really bad and makes it hard to tap on the notification. This was not the case in 4.1 or previous versions. So I want to make sure I am doing this correctly before I file a bug.

回答1:

I resolved this issue by calling setWhen(0) on my Notification.Builder. It seems Android's default value for this argument doesn't suit updating bits of the notification view without the entire notification fading out / in.

Notification.Builder builder = new Notification.Builder(c)
                .setContentTitle("Notification Title")
                .setSmallIcon(R.drawable.ic_notification_icon)
                .setProgress(max_progress,current_progress,false)
                .setWhen(0);
                notification = builder.getNotification();

mNotificationManager.notify(NOTIFICATION_ID, notification);

Update:

As WolframRittmeyer stated, using when=0 is not an elegant way. I formed a solution like following:

if(mNotif == null) {
//either setting mNotif first time
//or was lost when app went to background/low memory
    mNotif = createNewNotification();
}
else {
    long oldWhen = mNotif.when;
    mNotif = createNewNotification();
    mNotif.when = oldWhen;
}
mNotificationManager.notify(NOTIFICATION_ID, mNotif);

回答2:

What you are doing is correct, you're just missing the flags you can set. I don't know your particular notification implementation but you might consider using:

setOngoing(boolean ongoing)

or

setOnlyAlertOnce(boolean onlyAlertOnce)

回答3:

I'm guessing (since I had the same trouble just now) that you are using a RemoteView in your notification. I managed to update the notification without it flashing like this:

RemoteViews views;
if( this.mNotification == null) {
    views = new RemoteViews(getPackageName(), R.layout.notification);
    this.mNotification = new Notification.Builder(this)
        .setContent(views)
        .setSmallIcon(R.drawable.status_icon)
        .setContentIntent(mNotificationAction)
        .setOngoing(true)
        .setOnlyAlertOnce(true)
        .getNotification();
} else {
    views = this.mNotification.contentView;
}

Thanks to @seanmonstar for answering Refresh progress bar in notification bar.

回答4:

The solution described here works well: Updating an ongoing notification quietly

The key is to use to reuse the builder and setOnlyAlertOnce(true):

if (firstTime) {
  mBuilder.setSmallIcon(R.drawable.icon)
  .setContentTitle("My Notification") 
  .setOnlyAlertOnce(true); 
  firstTime = false;
} 
mBuilder.setContentText(message)
.setProgress(100, progress, true);

mNotificationManager.notify(mNotificationId, mBuilder.build());