问题
Two log showing
1: Use of stream types is deprecated for operations other than volume control
2: See the documentation of setSound() for what to use instead with android.media.AudioAttributes to qualify your playback use case
回答1:
From the developer documentation:
When you target Android 8.0 (API level 26), you must implement one or more notification channels to display notifications to your users.
int NOTIFICATION_ID = 234;
NotificationManager notificationManager = (NotificationManager) ctx.getSystemService(Context.NOTIFICATION_SERVICE);
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
String CHANNEL_ID = "my_channel_01";
CharSequence name = "my_channel";
String Description = "This is my channel";
int importance = NotificationManager.IMPORTANCE_HIGH;
NotificationChannel mChannel = new NotificationChannel(CHANNEL_ID, name, importance);
mChannel.setDescription(Description);
mChannel.enableLights(true);
mChannel.setLightColor(Color.RED);
mChannel.enableVibration(true);
mChannel.setVibrationPattern(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400});
mChannel.setShowBadge(false);
notificationManager.createNotificationChannel(mChannel);
}
NotificationCompat.Builder builder = new NotificationCompat.Builder(ctx, CHANNEL_ID)
.setSmallIcon(R.mipmap.ic_launcher)
.setContentTitle(title)
.setContentText(message);
Intent resultIntent = new Intent(ctx, MainActivity.class);
TaskStackBuilder stackBuilder = TaskStackBuilder.create(ctx);
stackBuilder.addParentStack(MainActivity.class);
stackBuilder.addNextIntent(resultIntent);
PendingIntent resultPendingIntent = stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);
builder.setContentIntent(resultPendingIntent);
notificationManager.notify(NOTIFICATION_ID, builder.build());
One interesting thing to note: If a channel already exists, calling createNotificationChannel has no effect, so you can create all channels whenever you start your application.
回答2:
Gulzar Bhat's answer is working perfectly if your minimum API is Oreo. If your minimum is lower however, you have to wrap the NotificationChannel code in a platform level check. After that you can still use the id, which will be ignored pre Oreo:
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
int importance = NotificationManager.IMPORTANCE_LOW;
NotificationChannel notificationChannel = new NotificationChannel(NOTIFICATION_CHANNEL_ID, NOTIFICATION_CHANNEL_NAME, importance);
notificationChannel.enableLights(true);
notificationChannel.setLightColor(Color.RED);
notificationChannel.enableVibration(true);
notificationChannel.setVibrationPattern(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400});
notificationManager.createNotificationChannel(notificationChannel);
}
NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(context, NOTIFICATION_CHANNEL_ID);
NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.notify((int)(System.currentTimeMillis()/1000), mBuilder.build());
回答3:
You can solve this in two ways but for both of them you need to create a notification channel with an specific channel id.
NotificationManager mNotificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
String id = "my_channel_01";
int importance = NotificationManager.IMPORTANCE_LOW;
NotificationChannel mChannel = new NotificationChannel(id, name,importance);
mChannel.enableLights(true);
mNotificationManager.createNotificationChannel(mChannel);
First way is to set channel for notification in constructor:
Notification notification = new Notification.Builder(MainActivity.this , id).setContentTitle("Title");
mNotificationManager.notify("your_notification_id", notification);
Second way is to set the channel by Notificiation.Builder.setChannelId()
Notification notification = new Notification.Builder(MainActivity.this).setContentTitle("Title").
setChannelId(id);
mNotificationManager.notify("your_notification_id", notification);
Hope this helps
回答4:
First create the notification channel:
public static final String NOTIFICATION_CHANNEL_ID = "4655";
//Notification Channel
CharSequence channelName = NOTIFICATION_CHANNEL_NAME;
int importance = NotificationManager.IMPORTANCE_LOW;
NotificationChannel notificationChannel = new NotificationChannel(NOTIFICATION_CHANNEL_ID, NOTIFICATION_CHANNEL_NAME, importance);
notificationChannel.enableLights(true);
notificationChannel.setLightColor(Color.RED);
notificationChannel.enableVibration(true);
notificationChannel.setVibrationPattern(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400});
NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.createNotificationChannel(notificationChannel);
then use the channel id in the constructor:
final NotificationCompat.Builder builder = new NotificationCompat.Builder(context, NOTIFICATION_CHANNEL_ID)
.setDefaults(Notification.DEFAULT_ALL)
.setSmallIcon(R.drawable.ic_timers)
.setVibrate(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400})
.setSound(null)
.setContent(contentView)
.setPriority(NotificationCompat.PRIORITY_DEFAULT)
.setLargeIcon(picture)
.setTicker(sTimer)
.setContentIntent(timerListIntent)
.setAutoCancel(false);
回答5:
This issue is related to the old FCM version.
Update your dependency to
com.google.firebase:firebase-messaging:15.0.2
or higher.
This will fix the error
failed to post notification on channel null
when your app receives notifications in the background because now Firebase provides a default notification channel with basic settings.
But you also can specify the default Notification Channel for FCM in the manifest.
<meta-data
android:name="com.google.firebase.messaging.default_notification_channel_id"
android:value="@string/default_notification_channel_id"/>
To learn more here
回答6:
I had a similar problem but starting an service as a background activity, in the service this code worked:
public static final int PRIMARY_FOREGROUND_NOTIF_SERVICE_ID = 1001;
@Override
public void onCreate() {
super.onCreate();
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
String id = "_channel_01";
int importance = NotificationManager.IMPORTANCE_LOW;
NotificationChannel mChannel = new NotificationChannel(id, "notification", importance);
mChannel.enableLights(true);
Notification notification = new Notification.Builder(getApplicationContext(), id)
.setSmallIcon(R.drawable.ic_launcher)
.setContentTitle("My chat")
.setContentText("Listening for incoming messages")
.build();
NotificationManager mNotificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
if (mNotificationManager != null) {
mNotificationManager.createNotificationChannel(mChannel);
mNotificationManager.notify(PRIMARY_FOREGROUND_NOTIF_SERVICE_ID, notification);
}
startForeground(PRIMARY_FOREGROUND_NOTIF_SERVICE_ID, notification);
}
}
It's not the best solution but just to start the service in the background It does work
回答7:
If you get this error should be paid attention to 2 items and them order:
NotificationChannel mChannel = new NotificationChannel(id, name, importance);builder = new NotificationCompat.Builder(this, id);
Also NotificationManager notifManager and NotificationChannel mChannel are created only once.
There are required setters for Notification:
builder.setContentTitle() // required
.setSmallIcon() // required
.setContentText() // required
See the example in On Android 8.1 API 27 notification does not display.
回答8:
String CHANNEL_ID = "my_channel";
NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this,CHANNEL_ID);
来源：https://stackoverflow.com/questions/45711925/failed-to-post-notification-on-channel-null-target-api-is-26