franky47
commented
4 years ago Indeed, calling MIDI_CREATE_INSTANCE here will not help, since the MIDI interface will be destroyed after start_midi returns, so it needs to be stored somewhere. Also, since version 5, the interface also needs a Transport object, to translate raw MIDI data into packets or serial streams. This is usually what the macro takes care of, but we'll see how it works internally and how to adapt it to your case.
There are two places you could store these objects. Either in global scope, or encapsulated in the class as members. It depends how your class object will be created and used, but by the looks of it this class has a run method that never returns, effectively encapsulating the setup / loop functions of Arduino into the class object, so either way will have the same effect.
In global scope, we'll have to use extern, so that inclusions of Test.h in several compilation units (.cpp/.ino files) don't generate multiple objects (however this is unlikely in the case of Arduino):
// Test.h
#pragma once
#include <MIDI.h>
// Define your transport
extern MIDI_NAMESPACE::SerialMIDI<HardwareSerial> serialMIDI;
// Define the MIDI interface
extern MIDI_NAMESPACE::MidiInterface<MIDI_NAMESPACE::SerialMIDI<HardwareSerial>>;
class Test
{
public:
void start_midi()
{
MIDI.begin();
}
void nostop_reading_midi()
{
// Add the rest of the code around here
MIDI.read();
}
};
// main-sketch.ino --
#include <Test.h>
// Here we actually create the MIDI interface, that we previously declared, and bind it to Serial1.
MIDI_CREATE_INSTANCE(HardwareSerial, Serial1, MIDI);To encapsulate the interface as a class member:
// Test.h
#pragma once
#include <MIDI.h>
class Test
{
private:
// Let's define some shorthand types:
using MidiTransport = MIDI_NAMESPACE::SerialMIDI<HardwareSerial>;
using MidiInterface = MIDI_NAMESPACE::MidiInterface<MidiTransport>;
MidiTransport midiTransport;
MidiInterface midiInterface;
public:
// In the constructor, which creates the member objects,
// we bind the Serial1 port to the transport, and the
// transport to the MIDI interface:
Test()
: midiTransport(Serial1)
, midiInterface((MidiTransport&)midiTransport)
{
}
void start_midi()
{
midiInterface.begin();
}
void nostop_reading_midi()
{
// Add the rest of the code around here
midiInterface.read();
}
};
// main-sketch.ino --
#include <Test.h>
// No need to create the MIDI objects here,
// they will be created as part of the `test` object:
Test test;
void setup()
{
test.start_midi();
}
void loop()
{
test.nostop_reading_midi();
}
SandroGrassia
Kprellz
SunboX
lathoub
Hi, I'm trying to use MIDI.h inside a class, and use MIDI' s functions in separated methods of this class; for example:
class Test.h:
Of course this code generates errors, because MIDI was not declared in nostop_reading_midi(void)... Can you please me give me any help? Thank you! PS: I apologize ... cannot find the way to get the right visualization of indentation!!