public class MainActivity extends WearableActivity {
    private TextView mTextView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTextView = (TextView) findViewById(R.id.text);
        int notificationId = 001;
        // The channel ID of the notification.
        String id = "my_channel_01";
        // Build intent for notification content
        Intent viewIntent = new Intent(this, MainActivity.class);
        viewIntent.putExtra("EXTRA_EVENT_ID", 1);
        PendingIntent viewPendingIntent =
                PendingIntent.getActivity(this, 0, viewIntent, 0);
        createNotificationChannel();
        // Notification channel ID is ignored for Android 7.1.1
        // (API level 25) and lower.
        NotificationCompat.Builder notificationBuilder =
                new NotificationCompat.Builder(this, id)
                        .setSmallIcon(R.drawable.common_google_signin_btn_icon_dark)
                        .setContentTitle("Hello World")
                        .setContentText("eventLocation")
                        .setContentIntent(viewPendingIntent);
        // Get an instance of the NotificationManager service
        NotificationManagerCompat notificationManager =
                NotificationManagerCompat.from(this);
        // Issue the notification with notification manager.
        notificationManager.notify(notificationId, notificationBuilder.build());
        // Enables Always-on
        setAmbientEnabled();
    }
    private void createNotificationChannel() {
        // Create the NotificationChannel, but only on API 26+ because
        // the NotificationChannel class is new and not in the support library
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            CharSequence name = "Test";
            String description = "Notification for Wear OS";
            int importance = NotificationManager.IMPORTANCE_DEFAULT;
            NotificationChannel channel = new NotificationChannel("1", name, importance);
            channel.setDescription(description);
            // Register the channel with the system; you can't change the importance
            // or other notification behaviors after this
            NotificationManager notificationManager = getSystemService(NotificationManager.class);
            notificationManager.createNotificationChannel(channel);
        }
    }
}

private void createNotificationChannel() {
    // 仅在API 26+上创建NotificationChannel，因为
    // NotificationChannel类是新的，不在支持库中
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        String id = "my_channel_01";
        CharSequence name = "Test";
        String description = "Notification for Wear OS";
        int importance = NotificationManager.IMPORTANCE_DEFAULT;
        NotificationChannel channel = new NotificationChannel(id, name, importance);
        channel.setDescription(description);
        // 将通道注册到系统中；在此之后无法更改重要性
        // 或其他通知行为
        NotificationManager notificationManager = getSystemService(NotificationManager.class);
        notificationManager.createNotificationChannel(channel);
    }
}