如何关闭 MIDI 设备？

Question

如何在 java 中关闭 MIDI 设备？我已尝试重新初始化 MidiHandler 对象，但设备保持打开状态，直到程序终止。此外，如果我在程序处于运行时拔下我的 MIDI 控制器，它在重新连接后不会发送音符，即使在重新初始化后也是如此。我必须再次终止并重新启动该程序，以使其正常工作。我对使用 MIDI 很陌生，所以我可能从根本上误解了整个概念。这是我目前所拥有的：

public class MidiHandler {
MidiDevice device;
MidiDevice.Info[] infos = MidiSystem.getMidiDeviceInfo();

public MidiHandler() {

    for (int i = 0; i < infos.length; i++) {
        try {
            this.device = MidiSystem.getMidiDevice(this.infos[i]);
            // does the device have any transmitters?
            // if it does, add it to the device list
            System.out.println(this.infos[i]);

            // get all transmitters
            List<Transmitter> transmitters = this.device.getTransmitters();
            // and for each transmitter

            for (int j = 0; j < transmitters.size(); j++) {
                // create a new receiver
                transmitters.get(j).setReceiver(
                // using my own MidiInputReceiver
                        new MidiInputReceiver(this.device.getDeviceInfo()
                                .toString()));
            }

            Transmitter trans = this.device.getTransmitter();
            trans.setReceiver(new MidiInputReceiver(this.device.getDeviceInfo()
                    .toString()));
            this.device.open();
        } catch (MidiUnavailableException e) {
        }
    }

}

public void close() {

}

public String getInfos() {
    String infos = "";
    for(int i = 0; i < this.infos.length; i++) {
        infos += "\n" + this.infos[i] + " ";
    }
    return infos;
}

// tried to write my own class. I thought the send method handles an
// MidiEvents sent to it
public class MidiInputReceiver implements Receiver {
    Synthesizer synth;
    MidiChannel[] mc;
    Instrument[] instr;
    int instrument;
    int channel;

    public MidiInputReceiver(String name) {
        try
        {
            patcher p = new patcher();
            this.instrument = p.getInstrument();
            this.channel = p.getChannel();
            this.synth = MidiSystem.getSynthesizer();
            this.synth.open();
            this.mc = synth.getChannels();
            instr = synth.getDefaultSoundbank().getInstruments();
            this.synth.loadInstrument(instr[1]);
            mc[this.channel].programChange(0, this.instrument);
        }
        catch (MidiUnavailableException e)
        {
            e.printStackTrace();
            System.exit(1);
        }
    }

    public void send(MidiMessage msg, long timeStamp) {
        /*
         * Use to display midi message
         */ 
        for(int i = 0; i < msg.getMessage().length; i++) {
            System.out.print("[" + msg.getMessage()[i] + "] ");

        }
        System.out.println();

        if (msg.getMessage()[0] == -112) {
            mc[this.channel].noteOn(msg.getMessage()[1], msg.getMessage()[2]+1000);
        }

        if (msg.getMessage()[0] == -128) {
            mc[this.channel].noteOff(msg.getMessage()[1], msg.getMessage()[2]+1000);
        }

    }

    public void close() {
    }
}

主要 class 只是实例化一个 MidiHandler 并且工作正常，除了上述问题。

Answer 1

你检查过了吗Oracle MIDI-messages？

Closing Connections

Once you're done with a connection, you can free up its resources by invoking the close method for each transmitter and receiver that you've obtained. The Transmitter and Receiver interfaces each have a close method. Note that invoking Transmitter.setReceiver doesn't close the transmitter's current receiver. The receiver is left open, and it can still receive messages from any other transmitter that's connected to it.

If you're also done with the devices, you can similarly make them available to other application programs by invoking MidiDevice.close(). Closing a device automatically closes all its transmitters and receivers.

Answer 2

您可以拨打MidiDevice::close()

explicit closing is done by calling close()

但是MIDI设备扩展Autocloseable，所以，根据API，你必须关闭Transmitter或Receiver。

在API中：

The device is closed after the last Receiver or Transmitter has been closed. On the other hand, calling getReceiver or getTransmitter on the device instance directly does not open the device implicitly. Closing these Transmitters and Receivers does not close the device implicitly.

如何关闭 MIDI 设备？

How to close a midi device?

java

midi

javax.sound.midi