Notificaton通知栏显示不出来

今天在写一个demo时，通知栏死活显示不出来，通过各种百度，终于解决了。

解决方法：

= "channel_01";
            String name="我是渠道名字";

            //启动浏览器
            Intent contentIntent = new Intent();
            contentIntent.setData(Uri.parse("http://www.baidu.com"));//Url 就是你要打开的网址
            contentIntent.setAction(Intent.ACTION_VIEW);

            //点击通知栏做的事
            PendingIntent  pendingIntent = PendingIntent.getActivity(this, 1, contentIntent, PendingIntent.FLAG_CANCEL_CURRENT);

            //获取系统通知服务
            NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
            Notification notification = null;
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                NotificationChannel mChannel = new NotificationChannel(id, name, NotificationManager.IMPORTANCE_LOW);
                Toast.makeText(this, mChannel.toString(), Toast.LENGTH_SHORT).show();
                notificationManager.createNotificationChannel(mChannel);
                notification = new Notification.Builder(this)
                        .setContentTitle("新消息1")
                        .setContentText("Hello world")
                        .setSmallIcon(R.mipmap.ic_launcher)
                        .setChannelId(id)
                        .setContentIntent(pendingIntent)//设置pendingIntent,点击通知时就会用到
                        .build();
            } else {
                notification = new NotificationCompat.Builder(this)
                        .setContentTitle("新消息2")
                        .setContentText("Hello world")
                        .setSmallIcon(R.mipmap.ic_launcher)
                        .setOngoing(true)
                        .setChannelId(id)
                        .setContentIntent(pendingIntent) //设置pendingIntent,点击通知时就会用到
                        .build();
            }

            notificationManager.notify(0, notification);

谢谢阅读