如何在Android Nougat及以上版本中创建Notification.contentView？

Question

I use Notification.contentView to replicate notification views:

View notificationView = notification.contentView.apply(context, parent);

Unfortunately as of version N, Notification.contentView may be null and deprecated, so how can I create Notification.contentView manually?

Generally I create notification this way:

NotificationCompat.Builder builder = new NotificationCompat.Builder(this, NOTIFICATION_CHANNEL_ID);
builder.setAutoCancel(true)
        .setColor(ContextCompat.getColor(this, R.color.colorAccent))
        .setContentTitle(title)
        .setContentText(text)
        .setDefaults(Notification.DEFAULT_ALL)
        .setWhen(when)
        .setSmallIcon(smallIcon);

Then if I create the contentView manually, what can I do to map all the above settings?
Important note: I don't call setCustomContentView, I want to reproduce a contentView for the standard notification.

Answer 1

Notification.contentView()

• YES From android N , this field may be null

• The notification view is determined by the inputs to Notification.Builder; a custom RemoteViews can optionally be supplied with Notification.Builder.setCustomContentView(RemoteViews)

SAMPLE CODE

    NotificationManager mNotificationManager =
            (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

    String NOTIFICATION_CHANNEL_ID = "Nilesh_channel";

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        NotificationChannel notificationChannel = new NotificationChannel(NOTIFICATION_CHANNEL_ID, "Your Notifications",
                NotificationManager.IMPORTANCE_HIGH);

        notificationChannel.setDescription("");
        notificationChannel.enableLights(true);
        notificationChannel.enableVibration(true);
        mNotificationManager.createNotificationChannel(notificationChannel);
    }

    NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this, NOTIFICATION_CHANNEL_ID);

    RemoteViews notificationView = new RemoteViews(getPackageName(), R.layout.custom_layout);

    notificationBuilder.setAutoCancel(true)
            .setColor(ContextCompat.getColor(this, R.color.colorAccent))
            .setContentTitle(getString(R.string.app_name))
            .setContentText("")
            .setDefaults(Notification.DEFAULT_ALL)
            .setWhen(System.currentTimeMillis())
            .setSmallIcon(R.drawable.ic_launcher_background)
            .setCustomContentView(notificationView) // set here your RemoteViews
            .setAutoCancel(true);

OUTPUT

Answer 2

Answer my own question:
Create contentView by Notification.Builder :

builder.createContentView();

Create contentView by Notification :

Notification.Builder.recoverBuilder(context, notification).createContentView();

Since Notification.Builder.createContentView() was introduced in api level 24, so the above code can only be called from Nougat 7.0 or newer devices; For a lower version phones, it's always safe to reference non-null Notification.contentView directly, it's created automatically by the android system after builder.build() was called.