Java Swing-MIDI钢琴第一步_Java_Swing

Java Swing-MIDI钢琴第一步

java swing

Java Swing-MIDI钢琴第一步,java,swing,Java,Swing,我只是在我创建这个项目的第一阶段，但我已经迷路了。在我的课堂上，我们主要关注AWT，但在这个项目中，我被告知要学习swing 现在，我正在试验布局，将按键放置在正常键盘的正确位置。我真的需要你帮我把布局弄清楚。如果有人能解释并提供代码，那就太棒了。谢谢代码：布局管理器实际上是为组件的二维定位而设计的对于钢琴来说，您希望黑键位于白键之上，因此在这种情况下，您可能希望使用空布局，以便可以控制每个组件的位置。这意味着您现在负责设置每个组件的大小/位置首先将黑键添加到面板，然后添加白键我给你一

我只是在我创建这个项目的第一阶段，但我已经迷路了。在我的课堂上，我们主要关注AWT，但在这个项目中，我被告知要学习swing

现在，我正在试验布局，将按键放置在正常键盘的正确位置。我真的需要你帮我把布局弄清楚。如果有人能解释并提供代码，那就太棒了。谢谢

代码：

布局管理器实际上是为组件的二维定位而设计的

对于钢琴来说，您希望黑键位于白键之上，因此在这种情况下，您可能希望使用空布局，以便可以控制每个组件的位置。这意味着您现在负责设置每个组件的大小/位置

首先将黑键添加到面板，然后添加白键

我给你一点提示。您的主面板将如下所示：

JPanel contentPane = new JPanel(null)
{
    @Override
    public Dimension getPreferredSize()
    {
        int count = getComponentCount();
        Component last = getComponent(count - 1);
        Rectangle bounds = last.getBounds();
        int width = 10 + bounds.x + bounds.width;
        int height = 10 + bounds.y + bounds.height;

        return new Dimension(width, height);
    }

    @Override
    public boolean isOptimizedDrawingEnabled()
    {
        return false;
    }
};

package experimental;

import static experimental.Experimental.KeyColor.BLACK;
import static experimental.Experimental.KeyColor.WHITE;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLayeredPane;
import javax.swing.SwingUtilities;

class Experimental {
  static final int WHITE_KEY_WIDTH = 48;
  static final int WHITE_KEY_HEIGHT = 300;
  static final int BLACK_KEY_WIDTH = 32;
  static final int BLACK_KEY_HEIGHT = 210;

  enum KeyColor { WHITE, BLACK };

  enum PitchClass {
    A("A", WHITE),
    A_SHARP("A#", BLACK),
    B("B", WHITE),
    C("C", WHITE),
    C_SHARP("C#", BLACK),
    D("D", WHITE),
    D_SHARP("D#", BLACK),
    E("E", WHITE),
    F("F", WHITE),
    F_SHARP("F#", BLACK),
    G("G", WHITE),
    G_SHARP("G#", BLACK),
    ;

    final String name;
    final KeyColor color;

    PitchClass(String name, KeyColor color) {
      this.name = name;
      this.color = color;
    }
  }

  public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {
      @Override
      public void run() {
        JFrame frame = new JFrame("Keyboard");
        JLayeredPane keyboard = new JLayeredPane();
        frame.add(keyboard);
        addKeys(keyboard);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(2000, 500);
        frame.setVisible(true);
      }

      private void addKeys(JLayeredPane keyboard) {
        int x = 0;
        int keyCount = 0;
        for (int octave = 1; ; ++octave) {
          for (PitchClass note : PitchClass.values()) {
            JButton key = new JButton(note.name);
            key.setOpaque(true);
            key.setActionCommand(String.format("%d/%s", octave, note.name));
            if (note.color == WHITE) {
              key.setBounds(x, 0, WHITE_KEY_WIDTH, WHITE_KEY_HEIGHT);
              keyboard.add(key, new Integer(0));
              x += WHITE_KEY_WIDTH;
            } else {
              key.setBounds(x - BLACK_KEY_WIDTH / 2, 0, BLACK_KEY_WIDTH, BLACK_KEY_HEIGHT);
              keyboard.add(key, new Integer(1));
            }
            key.addMouseListener(new MouseAdapter() {
              @Override
              public void mousePressed(MouseEvent e) {
                super.mousePressed(e); 
                if (e.getButton() == 1) {
                  System.out.println("Press: "+ ((JButton) e.getSource()).getActionCommand());
                }
              }
              @Override
              public void mouseReleased(MouseEvent e) {
                super.mouseReleased(e);
                if (e.getButton() == 1) {
                  System.out.println("Release: "+ ((JButton) e.getSource()).getActionCommand());
                }
              }
            });
            if (++keyCount == 40) return;
          }
        }
      }
    });
  }
}

由于白键是最后添加的，因此面板上的最后一个组件将是白键。因此，该组件用于确定面板的首选尺寸，以适合所有白键

isOptimizedDrawingEnabled（）

方法将被重写，因为组件将堆叠在另一个组件之上。这将确保黑键始终绘制在白键之上。

实际上，JLayeredPane设计用于实现您想要的功能：按指定的z顺序重叠小部件。大概是这样的：

JPanel contentPane = new JPanel(null)
{
    @Override
    public Dimension getPreferredSize()
    {
        int count = getComponentCount();
        Component last = getComponent(count - 1);
        Rectangle bounds = last.getBounds();
        int width = 10 + bounds.x + bounds.width;
        int height = 10 + bounds.y + bounds.height;

        return new Dimension(width, height);
    }

    @Override
    public boolean isOptimizedDrawingEnabled()
    {
        return false;
    }
};

package experimental;

import static experimental.Experimental.KeyColor.BLACK;
import static experimental.Experimental.KeyColor.WHITE;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLayeredPane;
import javax.swing.SwingUtilities;

class Experimental {
  static final int WHITE_KEY_WIDTH = 48;
  static final int WHITE_KEY_HEIGHT = 300;
  static final int BLACK_KEY_WIDTH = 32;
  static final int BLACK_KEY_HEIGHT = 210;

  enum KeyColor { WHITE, BLACK };

  enum PitchClass {
    A("A", WHITE),
    A_SHARP("A#", BLACK),
    B("B", WHITE),
    C("C", WHITE),
    C_SHARP("C#", BLACK),
    D("D", WHITE),
    D_SHARP("D#", BLACK),
    E("E", WHITE),
    F("F", WHITE),
    F_SHARP("F#", BLACK),
    G("G", WHITE),
    G_SHARP("G#", BLACK),
    ;

    final String name;
    final KeyColor color;

    PitchClass(String name, KeyColor color) {
      this.name = name;
      this.color = color;
    }
  }

  public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {
      @Override
      public void run() {
        JFrame frame = new JFrame("Keyboard");
        JLayeredPane keyboard = new JLayeredPane();
        frame.add(keyboard);
        addKeys(keyboard);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(2000, 500);
        frame.setVisible(true);
      }

      private void addKeys(JLayeredPane keyboard) {
        int x = 0;
        int keyCount = 0;
        for (int octave = 1; ; ++octave) {
          for (PitchClass note : PitchClass.values()) {
            JButton key = new JButton(note.name);
            key.setOpaque(true);
            key.setActionCommand(String.format("%d/%s", octave, note.name));
            if (note.color == WHITE) {
              key.setBounds(x, 0, WHITE_KEY_WIDTH, WHITE_KEY_HEIGHT);
              keyboard.add(key, new Integer(0));
              x += WHITE_KEY_WIDTH;
            } else {
              key.setBounds(x - BLACK_KEY_WIDTH / 2, 0, BLACK_KEY_WIDTH, BLACK_KEY_HEIGHT);
              keyboard.add(key, new Integer(1));
            }
            key.addMouseListener(new MouseAdapter() {
              @Override
              public void mousePressed(MouseEvent e) {
                super.mousePressed(e); 
                if (e.getButton() == 1) {
                  System.out.println("Press: "+ ((JButton) e.getSource()).getActionCommand());
                }
              }
              @Override
              public void mouseReleased(MouseEvent e) {
                super.mouseReleased(e);
                if (e.getButton() == 1) {
                  System.out.println("Release: "+ ((JButton) e.getSource()).getActionCommand());
                }
              }
            });
            if (++keyCount == 40) return;
          }
        }
      }
    });
  }
}