[Android] I can't find a solution. 'Notification pop up' is required

[GWAK]

@akenaton

Dear akenaton,
Good morning.

I’m talking about Android mode version.

In Android mode 3.0
'mBuilder.setChannelId (CHANNEL_ID); 'Error.

However, in Android mode 4.0
'mBuilder.setChannelId (CHANNEL_ID); ’
It works.

This solved ‘Notification’.

But there was a problem.
Text is broken after Android Mode 4.0
help me.

Is there an Android Mode 4.1 problem(characters are broken.) / solution?

‘Foreign language is not expressed.’ Even if you change the font, the characters are broken. ex) Korean, Japanese, Chinese, etc. [problem] println() does not work. Is there a solution? Help. I need your help.