android O以后版本 自定义Notification

最近在使用通知的时候，发现方法执行后，没有弹出通知，而是提示下面的错误：

Developer warning for package "com.example.test" Failed to post notification on channel "null" See log for more details.

经上网查证，是在Android O后 引入了一个叫NotificationChannel的类， 我们在sdk版本为26的时候，如果不加这个东西，就不能发通知。

所以务必在26以及之后的版本中添加 channelId。

    private void sendNotification() {

        Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.baidu.com"));
        PendingIntent pendingIntent = PendingIntent.getActivity(MainActivity.this,0,intent,0);

        NotificationManager manager = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);

        NotificationCompat.Builder builder = new NotificationCompat.Builder(MainActivity.this,"channel_1112");//一定要添加channelId,否则会报错Fail to post notification on channel "null"

        builder.setSmallIcon(R.mipmap.ic_launcher);  //此条件必须设置，不然不能显示
        RemoteViews view = new RemoteViews(getPackageName(), R.layout.notify_custom_layout); //自定义布局
        builder.setContent(view);

        if(Build.VERSION.SDK_INT >= 26)
        {
            //当sdk版本大于26
            String id = "channel_1112";
            String description = "143";
            int importance = NotificationManager.IMPORTANCE_LOW;
            NotificationChannel channel = new NotificationChannel(id, description, importance);
                     channel.enableLights(true);
                     channel.enableVibration(true);
            if (manager != null) {
                manager.createNotificationChannel(channel);
            }
            manager.notify(1, builder.build());

/*                     //使用系统样式
                     Notification notification = new Notification.Builder(MainActivity.this, id)
                    .setCategory(Notification.CATEGORY_MESSAGE)
                    .setSmallIcon(R.mipmap.ic_launcher)
                    .setContentTitle("This is a content title")
                    .setContentText("This is a content text")
                    .setContentIntent(pendingIntent)
                    .setAutoCancel(true)
                    .setWhen(System.currentTimeMillis())
                    .setDefaults(Notification.DEFAULT_ALL)
                    .setPriority(Notification.PRIORITY_MAX)
                    .setFullScreenIntent(pendingIntent, true)
                    .build();
            manager.notify(1, notification);*/

        }
        else
        {
            //当sdk版本小于26
            Notification notification = new NotificationCompat.Builder(MainActivity.this)
                    .setContentTitle("This is content title")
                    .setContentText("This is content text")
                    .setContentIntent(pendingIntent)
                    .setSmallIcon(R.mipmap.ic_launcher)
                    .build();
            manager.notify(1,notification);
        }
}