java - doClick 在循环结束之前不释放按键

Question

我正在用 Java 制作一个钢琴应用程序。这是功能之一，

public void playOnce(int time) {
    play();
    doClick(time);
    stop();
}

public void play() {
    channel[0].noteOn(note, 60);
}

public void stop() {
    channel[0].noteOff(note);
}

如果有必要，我将提供一个最小的工作示例，但我想确保这不是一个明显的问题。问题是 playOnce 在 while 循环中被调用。 playOnce 属于 Key 类，每个 Key 都有不同的音符。在 while 循环的每次迭代中，都会在不同的键上调用 playOnce。一旦所有的键都被弹奏完毕，它就会停止。

doClick 方法正确按下了按键，但直到所有按键都被按下后才会释放。事实上，在弹奏琴键时，您无法执行任何操作，甚至不能按暂停按钮。对于这个问题，我想我可以将整个循环放在不同的线程中，但我认为这种解决方案不会允许释放 key 。

编辑:是的，我发现我需要一个新线程来使其他操作正常工作，但我仍然需要修复 doClick()。这可能比我想象的更复杂，所以这是一个工作示例，

Main.java

import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.text.DecimalFormat;

import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLayeredPane;
import javax.swing.JPanel;
import javax.swing.JSpinner;
import javax.swing.JTextArea;
import javax.swing.SpinnerNumberModel;

public class Main implements ActionListener {

    final int WHITE_KEY_WIDTH, WHITE_KEY_HEIGHT, BLACK_KEY_WIDTH,
            BLACK_KEY_HEIGHT;
    final int WIDTH;
    final JFileChooser fc;
    {
        WHITE_KEY_WIDTH = Key.WHITE_KEY_WIDTH;
        BLACK_KEY_WIDTH = Key.BLACK_KEY_WIDTH;
        WHITE_KEY_HEIGHT = Key.WHITE_KEY_HEIGHT;
        BLACK_KEY_HEIGHT = Key.BLACK_KEY_HEIGHT;
        WIDTH = 3 * (WHITE_KEY_WIDTH * 7) + WHITE_KEY_WIDTH;
        fc = new JFileChooser();
    }

    public static Key keys[] = new Key[48];
    private static int index = 0;
    private String prevText = "";

    JTextArea shabadEditor = null;
    JSpinner tempoControl;
    JFrame frame;
    File curFile;

    public static void main(String[] args) {
        new Main();
    }

    public Main() {
        frame = new JFrame();

        JPanel mainPanel = new JPanel();
        JPanel controlPanel = new JPanel();
        JLayeredPane pianoPanel = new JLayeredPane();

        mainPanel.setLayout(new GridBagLayout());

        JButton playButton = new JButton("Play");
        JButton pauseButton = new JButton("Pause");

        playButton.addActionListener(this);
        playButton.setActionCommand("play");

        pauseButton.addActionListener(this);
        pauseButton.setActionCommand("pause");

        SpinnerNumberModel model = new SpinnerNumberModel(1, 0, 2, .1);
        tempoControl = new JSpinner(model);
        JSpinner.NumberEditor editor = (JSpinner.NumberEditor) tempoControl
                .getEditor();
        DecimalFormat format = editor.getFormat();
        format.setMinimumFractionDigits(1);
        Dimension d = tempoControl.getPreferredSize();
        d.width = 40;
        tempoControl.setPreferredSize(d);

        GridBagConstraints c = new GridBagConstraints();
        // Construct each top level component
        controlPanel.add(playButton);
        controlPanel.add(pauseButton);
        controlPanel.add(tempoControl);
        shabadEditor = new JTextArea(20, 78);
        constructKeyboard(pianoPanel);

        // Add the piano panel and shabad editor to the window
        c.gridx = 0;
        c.gridy = 0;
        c.weightx = 1.0;
        c.anchor = GridBagConstraints.NORTHWEST;
        mainPanel.add(controlPanel, c);

        c.gridx = 0;
        c.gridy = 1;
        c.weightx = 1.0;
        // c.weighty = 1.0;
        c.anchor = GridBagConstraints.NORTHWEST;
        pianoPanel
                .setPreferredSize(new Dimension(WIDTH - 18, WHITE_KEY_HEIGHT));
        mainPanel.add(pianoPanel, c);

        c.gridx = 0;
        c.gridy = 2;
        c.weightx = 1.0;
        c.weighty = 1.0;
        c.anchor = GridBagConstraints.NORTHWEST;
        mainPanel.add(shabadEditor, c);
        frame.add(mainPanel);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(WIDTH, WHITE_KEY_HEIGHT * 3 + 30);
        frame.setLocation(250, 60);
        frame.setVisible(true);
    }

    void constructKeyboard(Container panel) {
        int i = 0;
        int j = 0;

        for (int k = 0; k < 3; k++) {
            addWhiteKey(panel, i++);
            addBlackKey(panel, j++);
            addWhiteKey(panel, i++);
            addBlackKey(panel, j++);
            addWhiteKey(panel, i++);
            addWhiteKey(panel, i++);
            j++;
            addBlackKey(panel, j++);
            addWhiteKey(panel, i++);
            addBlackKey(panel, j++);
            addWhiteKey(panel, i++);
            addBlackKey(panel, j++);
            j++;
            addWhiteKey(panel, i++);
        }
    }

    void addWhiteKey(Container panel, int i) {
        WhiteKey b = new WhiteKey();
        b.setLocation(i++ * WHITE_KEY_WIDTH, 0);
        panel.add(b, 0, -1);
        keys[index++] = b;
    }

    void addBlackKey(Container panel, int factor) {
        BlackKey b = new BlackKey();
        b.setLocation(WHITE_KEY_WIDTH - BLACK_KEY_WIDTH / 2 + factor
                * WHITE_KEY_WIDTH, 0);
        panel.add(b, 1, -1);
        keys[index++] = b;
    }

    @Override
    public void actionPerformed(ActionEvent arg0) {
        String action = arg0.getActionCommand();

        if (action.equals("play")) {
            System.out.println("working");
            for (int i = 0; i < 10; i++) {
                keys[i].playOnce(500);
            }
        }
    }
}

Key.java

import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.sound.midi.MidiChannel;
import javax.sound.midi.MidiSystem;
import javax.sound.midi.MidiUnavailableException;
import javax.sound.midi.Synthesizer;
import javax.swing.JButton;

public class Key extends JButton implements MouseListener {

    private static final long serialVersionUID = 1L;

    public static final int WHITE_KEY_HEIGHT = 200;
    public static final int WHITE_KEY_WIDTH = 40;
    public static final int BLACK_KEY_WIDTH = 20;
    public static final int BLACK_KEY_HEIGHT = 120;

    private static int noteCount = 40;
    public int note;

    private static Synthesizer synth = null;

    static {
        try {
            synth = MidiSystem.getSynthesizer();
            synth.open();
        } catch (MidiUnavailableException e) {
            e.printStackTrace();
        }
    }
    MidiChannel channel[];

    public Key() {
        note = noteCount++;

        // Instrument[] instruments = synth.getAvailableInstruments();
        // for (Instrument instrument : instruments) {
        // System.out.println(instrument.getName());
        // System.out.println(instrument.getPatch().getBank());
        // System.out.println(instrument.getPatch().getProgram());
        // }

        channel = synth.getChannels();
        channel[0].programChange(20);
        addMouseListener(this);
    }

    public void playOnce(int time) {
        play();
        doClick(time);
        stop();
    }

    public void play() {
        channel[0].noteOn(note, 60);
    }

    public void stop() {
        channel[0].noteOff(note);
    }

    @Override
    public void mouseClicked(MouseEvent e) {
        System.out.println(this.note);
    }

    @Override
    public void mouseEntered(MouseEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mouseExited(MouseEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mousePressed(MouseEvent e) {
        play();

    }

    @Override
    public void mouseReleased(MouseEvent e) {
        stop();
    }

}

BlackKey.java

import java.awt.Color;

public class BlackKey extends Key {

    private static final long serialVersionUID = 1L;

    public BlackKey() {
        super();
        setBackground(Color.BLACK);
        setSize(BLACK_KEY_WIDTH, BLACK_KEY_HEIGHT);
    }
}

WhiteKey.java

import java.awt.Color;

public class WhiteKey extends Key {

    private static final long serialVersionUID = 1L;

    public WhiteKey() {
        super();
        setBackground(Color.WHITE);
        setSize(WHITE_KEY_WIDTH, WHITE_KEY_HEIGHT);
    }

}

编辑:在对线程进行了一些工作之后，这就是我所拥有的

通过将 for 循环放在另一个线程中，可以在正确的时间释放按键:

@Override
    public void actionPerformed(ActionEvent arg0) {
        String action = arg0.getActionCommand();

        if (action.equals("play")) {
            System.out.println("working");
            new Thread(new Runnable() {
                public void run() {
                    for (int i = 0; i < 20; i++) {
                        keys[i].playOnce(100);
                    }
                }
            }).start();
        }
    }
}

现在的问题是键盘出现故障。键盘是使用分层 Pane 创建的，由于某种原因，当释放按键时，本应位于底部的层会出现在顶部。当我将鼠标悬停在它们上方时，故障就消失了。有什么想法吗？

EDIT2:我修复了故障。我只需添加

     try {
        Thread.sleep(10);
    } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

doClick()之后；

Answer 1

您的方法的问题是您阻塞了事件线程。该线程负责用户输入、绘画和窗口更新。我现在的猜测是，doClick 的超时在事件线程内进行检查(似乎合乎逻辑)，因此在您的 actionPerformed 方法退出之前它不会被释放(因此事件线程可以继续其事件处理)。

此问题的解决方案是(正如您已经提到的)将您的 for 循环移动到另一个线程并使用 SwingUtilities.invokeLater 调用 doClick .