How to play midi sound with the phone speaker?

Stupid question.

But I’m totally new to this area.
Is there someone could give me some clue to find out the solution?

After I read the API Doc and MidiTest example in JuceProjucer.
I’m very confused.The midi input output devices list always empty.
Is it the output device can be the phone speaker?
If I want to play midi sound use the phone speaker ,what should I do?
Please help me,thanks.

MIDI events are just notes. You need a synthesizer to actually synthesize the midi notes.

Thanks,is there any example code?
like a simple Midi Player that can play midi file?