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[英]Java MIDI - ControllerEventListener (How to change the instrument)
[英]Cannot change the MIDI instrument in Java
我已經粘貼了這個小的Java程序:我有8種音調(C,D,E,...,A,B,C),因此我可以支配窮人的鋼琴。
package net.coderodde.music;
import java.awt.Canvas;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.sound.midi.Instrument;
import javax.sound.midi.MidiChannel;
import javax.sound.midi.MidiSystem;
import javax.sound.midi.MidiUnavailableException;
import javax.sound.midi.Soundbank;
import javax.sound.midi.Synthesizer;
import javax.swing.JFrame;
public class KeyboardPiano {
private static final String APP_TITLE = "Keyboard Piano";
private final JFrame frame = new JFrame(APP_TITLE);
private final Canvas canvas = new Canvas();
private Synthesizer synthesizer;
private final MidiChannel[] midiChannels;
private final Instrument[] instruments;
private int instrumentIndex = 40;
KeyboardPiano() {
try {
synthesizer = MidiSystem.getSynthesizer();
synthesizer.open();
} catch (MidiUnavailableException ex) {
ex.printStackTrace();
System.exit(1);
}
this.midiChannels = synthesizer.getChannels();
Soundbank bank = synthesizer.getDefaultSoundbank();
synthesizer.loadAllInstruments(bank);
System.out.println("[STATE] MIDI channels: " + midiChannels.length);
this.instruments = synthesizer.getAvailableInstruments();
System.out.println("[STATE] Instruments: " + instruments.length);
synthesizer.loadAllInstruments(synthesizer.getDefaultSoundbank());
boolean b = synthesizer.loadInstrument(instruments[53]);
System.out.println(b);
}
private void init() {
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(canvas);
frame.setSize(100, 100);
frame.setResizable(false);
canvas.addKeyListener(new KeyboardPianoListener());
canvas.setFocusable(true);
canvas.requestFocus();
}
private void show() {
frame.setVisible(true);
}
public static void main(String[] args) {
KeyboardPiano keyboardPiano = new KeyboardPiano();
keyboardPiano.init();
keyboardPiano.show();
}
private final class KeyboardPianoListener implements KeyListener {
@Override
public void keyTyped(KeyEvent e) {
int keyCode = e.getExtendedKeyCode();
int noteNumber = -1;
switch (keyCode) {
case KeyEvent.VK_1: {
noteNumber = 60;
break;
}
case KeyEvent.VK_2: {
noteNumber = 62;
break;
}
case KeyEvent.VK_3: {
noteNumber = 64;
break;
}
case KeyEvent.VK_4: {
noteNumber = 65;
break;
}
case KeyEvent.VK_5: {
noteNumber = 67;
break;
}
case KeyEvent.VK_6: {
noteNumber = 69;
break;
}
case KeyEvent.VK_7: {
noteNumber = 71;
break;
}
case KeyEvent.VK_8: {
noteNumber = 72;
break;
}
case KeyEvent.VK_A: {
System.out.println("dec");
instrumentIndex = Math.max(0, instrumentIndex - 1);
synthesizer.loadInstrument(instruments[instrumentIndex]);
break;
}
case KeyEvent.VK_S: {
System.out.println("inc");
instrumentIndex = Math.min(instruments.length - 1,
instrumentIndex + 1);
synthesizer.loadInstrument(instruments[instrumentIndex]);
break;
}
}
if (noteNumber != -1) {
midiChannels[0].noteOn(noteNumber, 600);
}
}
@Override
public void keyPressed(KeyEvent e) {
}
@Override
public void keyReleased(KeyEvent e) {
}
}
}
在鍵偵聽器中,每當用戶鍵入A或S時,程序都應該更改樂器, 但不會發生 。 那么,我在這里想念什么?
loadInstrument()
不會執行您想要的操作。
要更改樂器,您需要發送一個programChange()
消息。
輸入字符后會觸發事件KEY_TYPED 。
您可以使用keyTyped()
在keyTyped()
檢索輸入的字符,或者在keyPressed()
移動代碼e.getKeyChar()
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