Exploring the Android MIDI API for Real-Time Music Control

Are you an Android developer with an interest in music? Or a musician hoping to create your own real-time music control app? The Android MIDI API, introduced in Android 6.0 (Marshmallow), provides developers a structured way to control and manipulate MIDI data. This article provides a comprehensive guide on how to use Android MIDI API for real-time music control.

Understanding MIDI

MIDI, which stands for Musical Instrument Digital Interface, is a protocol developed in the 1980s to allow electronic musical instruments, computers, and other related devices to communicate with each other. MIDI does not transmit an actual sound but sends information about the music, like pitch, velocity, and duration.

Android MIDI API allows developers to communicate with MIDI devices through USB, Bluetooth LE, and virtual MIDI devices.

Getting Started with Android MIDI API

To start using the Android MIDI API, you need to have at least Android 6.0 (API level 23) and Android Studio 2.2 or higher. Also, you need to add the MIDI feature to your manifest file:

<uses-feature android:name="android.software.midi" android:required="true" />

Key Components of the Android MIDI API

The Android MIDI API includes several key components used for MIDI communication:

• MidiManager: This class manages and enumerates MIDI devices.
• MidiDevice: It represents a MIDI device. Devices can have one or more MidiInputPort and MidiOutputPort.
• MidiInputPort: This is a port that can receive MIDI data.
• MidiOutputPort: This is a port that can send MIDI data.
• MidiReceiver: This is the destination to which MIDI data can be sent.
• MidiSender: This is the source of MIDI data.

Implementing the Android MIDI API

Once you’ve set up your environment, you can implement Android MIDI API. Here’s a basic outline of the steps:

1. Accessing the MidiManager

First, you need to get an instance of the MidiManager. The following code shows how to do this:

MidiManager midiManager = (MidiManager) getSystemService(Context.MIDI_SERVICE);

2. Enumerating MIDI Devices

Next, the MidiManager can be used to list available MIDI devices, as shown below:

MidiDeviceInfo[] infos = midiManager.getDevices();

3. Connecting to a MIDI Device

Once you have selected a device, you can open it with the openDevice method:

midiManager.openDevice(deviceInfo, new MidiManager.OnDeviceOpenedListener() {
    @Override
    public void onDeviceOpened(MidiDevice device) {
        if (device == null) {
            Log.e(TAG, "Could not open device");
        } else {
            // Use device
        }
    }
}, new Handler(Looper.getMainLooper()));

4. Sending and Receiving MIDI Data

After opening a device, you can get its MIDI input and output ports to send and receive MIDI data. Here is an example of sending a note-on message:

MidiOutputPort outputPort = device.openOutputPort(0);
byte[] buffer = new byte[32];
int numBytes = 0;
buffer[numBytes++] = (byte) (0x90 + (channel - 1)); // note on
buffer[numBytes++] = (byte) note; // pitch
buffer[numBytes++] = (byte) velocity; // velocity
outputPort.send(buffer, 0, numBytes);

Conclusion

Using the Android MIDI API, developers can create music applications that interact with MIDI devices in real time. While the API may seem complex at first, understanding its basic components and how they interact can make the process much easier. With this guide, you can start developing your own MIDI applications and contribute to the growing field of digital music.