一、问题表现

手机升级到Android 9.0测试的App的时候发现通知栏不显示了，之前Android 8.0显示还好好的，仔细研究了下，发现Android 8.0以后更新了API启用了以前创建通知栏方法。所以一般使用的时候还是最好使用新的API。

二、兼容方法

 /**
     * 开柜记录消息提醒
     *
     * @param context
     * @param title
     * @param msg
     */
    public static void showOpenHistoryNotice(Context context, String title, String msg) {
        NotificationManager manager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            // 创建
            NotificationChannel channel = new NotificationChannel(String.valueOf(id), "通知", NotificationManager.IMPORTANCE_DEFAULT);
            channel.enableLights(true);
            channel.setLightColor(ContextCompat.getColor(context, R.color.c_ff6633));
            channel.setShowBadge(true);
            channel.setDescription("互救吧");
            manager.createNotificationChannel(channel);
        }

        Intent clickIntent = new Intent(context, HomeMsgActivity.class);
        NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(context, String.valueOf(id));
        mBuilder.setContentTitle(title)
                .setContentText(msg)
                .setLargeIcon(BitmapFactory.decodeResource(context.getResources(), R.drawable.icon))
                .setOnlyAlertOnce(true)
                .setDefaults(Notification.DEFAULT_ALL)
                .setWhen(System.currentTimeMillis())
                .setSmallIcon(R.drawable.logo_white)
                .setColor(ContextCompat.getColor(context, R.color.c_ff6633));
        clickIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        PendingIntent clickPendingIntent = PendingIntent.getActivity(context, 0, clickIntent, PendingIntent.FLAG_CANCEL_CURRENT);
        // 点击删除
        Intent cancelIntent = new Intent(context, NoticeCancelBroadcastReceiver.class);
        cancelIntent.setAction("notice_cancel");
        cancelIntent.putExtra("id", id);
        PendingIntent cancelPendingIntent = PendingIntent.getBroadcast(context, 0, cancelIntent, PendingIntent.FLAG_ONE_SHOT);
        mBuilder.setContentIntent(clickPendingIntent);
        mBuilder.setDeleteIntent(cancelPendingIntent);
        mBuilder.setAutoCancel(true);
        manager.notify(id, mBuilder.build());

    }

Android 8.0以上添加NotificationChannel, id是通知栏id,在创建的时候最好直接使用，不然的话好像不会显示
PendingIntent 添加了点击和取消按钮

三、通知栏取消

通知栏取消只要注册一个静态广播就行了

/**
 * @author Wudi
 * @date 2018/9/17
 */
public class NoticeCancelBroadcastReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        String acton = intent.getAction();
        if (acton.equals("notice_cancel")) {
            int id = intent.getIntExtra("id", -1);
            if (id != -1) {
                NotificationManager notificationManager =
                        (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
                notificationManager.cancel(id);
            }
        }
    }
}