概要

KotlinSwingコンポーネントを使用するサンプルと、Javaからの変換に関するメモです。

実行環境

$ curl -s "https://get.sdkman.io" | bash 
$ sdk install kotlin
$ kotlinc -version
info: kotlinc-jvm 1.1.4-3 (JRE 1.8.0_141-b15)
$ kotlinc hello.kt -include-runtime -d hello.jar && "$JAVA_HOME/bin/java" -jar hello.jar

Swing + Kotlin サンプル

JTable

  • Class<?>Class<Any>Class<Object>Class<*>Class<out Any>に変換した方が良いかもしれない
    • IntelliJの自動変換ではClass<*>
  • Object#getClass()o.javaClass
  • オーバーライドの方法、@Overrideoverride
  • 配列、二次元配列
  • apply
  • switchwhen
  • DefaultTableModel#getColumnClass(...)メソッドをオーバーライドして、Boolean::class.javaを返してもセルレンダラーにJCheckBoxは適用されない
    • IntelliJの自動変換ではBoolean::class.javaになるが、java.lang.Boolean::class.javaに修正する必要がある

Java

import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;

public class JTableExample {
  public JComponent makeUI() {
    String[] cn = {"String", "Integer", "Boolean"};
    Object[][] data = {
      {"aaa", 12, true}, {"bbb", 5, false},
      {"CCC", 92, true}, {"DDD", 0, false}
    };
    TableModel m = new DefaultTableModel(data, cn) {
      @Override public Class<?> getColumnClass(int col) {
        return getValueAt(0, col).getClass();
      }
    };
    JTable table = new JTable(m);
    table.setAutoCreateRowSorter(true);

    JPanel p = new JPanel(new BorderLayout());
    p.add(new JScrollPane(table));
    return p;
  }
  public static void main(String... args) {
    EventQueue.invokeLater(() -> {
      JFrame f = new JFrame();
      f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      f.add(new JTableExample().makeUI());
      f.setSize(320, 240);
      f.setLocationRelativeTo(null);
      f.setVisible(true);
    });
  }
}

Kotlin

import java.awt.*
import javax.swing.*
import javax.swing.table.*

fun makeUI(): JComponent {
  val cn = arrayOf("String", "Integer", "Boolean")
  val data = arrayOf(
    arrayOf("aaa", 12, true), arrayOf("bbb", 5, false),
    arrayOf("CCC", 92, true), arrayOf("DDD", 0, false))
  val m = object: DefaultTableModel(data, cn) {
    override fun getColumnClass(col: Int): Class<Any> {
      return getValueAt(0, col).javaClass
    }
  }
  // val m = object: DefaultTableModel(data, cn) {
  //   override fun getColumnClass(col: Int): Class<*> {
  //     return when (col) {
  //       0 -> String::class.java
  //       1 -> Integer::class.java
  //       // XXX: 2 -> Boolean::class.java
  //       2 -> java.lang.Boolean::class.java
  //       else -> Object::class.java
  //     }
  //   }
  // }
  val table = JTable(m).apply {
    autoCreateRowSorter = true
  }
  return JPanel(BorderLayout(5, 5)).apply {
    add(JScrollPane(table))
  }
}
fun main(args: Array<String>) {
  EventQueue.invokeLater {
    JFrame("kotlin swing").apply {
      defaultCloseOperation = JFrame.EXIT_ON_CLOSE
      add(makeUI())
      size = Dimension(320, 240)
      setLocationRelativeTo(null)
      setVisible(true)
    }
  }
}

JTree

Java

import java.awt.*;
import java.util.*;
import javax.swing.*;

public class JTreeExample {
  public JComponent makeUI() {
    JTree tree = new JTree();

    JButton b1 = new JButton("expand");
    b1.addActionListener(e -> expandAll(tree));

    JButton b2 = new JButton("collapse");
    b2.addActionListener(e -> collapseAll(tree));

    JPanel pp = new JPanel(new GridLayout(1, 0, 5, 5));
    Arrays.asList(b1, b2).forEach(pp::add);
    JPanel p = new JPanel(new BorderLayout(5, 5));
    p.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
    p.add(new JScrollPane(tree));
    p.add(pp, BorderLayout.SOUTH);
    return p;
  }
  protected static void expandAll(JTree tree) {
    int row = 0;
    while (row < tree.getRowCount()) {
      tree.expandRow(row);
      row++;
    }
  }
  protected static void collapseAll(JTree tree) {
    int row = tree.getRowCount() - 1;
    while (row >= 0) {
      tree.collapseRow(row);
      row--;
    }
  }
  public static void main(String[] args) {
    EventQueue.invokeLater(() -> {
      JFrame f = new JFrame();
      f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      f.add(new JTreeExample().makeUI());
      f.setSize(320, 240);
      f.setLocationRelativeTo(null);
      f.setVisible(true);
    });
  }
}

Kotlin

import java.awt.*
import javax.swing.*

fun makeUI(): JComponent {
  val tree = JTree()
  val p = JPanel(GridLayout(1, 0, 5, 5)).apply {
    add(JButton("expand").apply {
      addActionListener { expandAll(tree) }
    })
    add(JButton("collapse").apply {
      addActionListener { collapseAll(tree) }
    })
  }
  return JPanel(BorderLayout(5, 5)).apply {
    setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5))
    add(JScrollPane(tree))
    add(p, BorderLayout.SOUTH)
  }
}
fun expandAll(tree: JTree) {
  var row = 0
  while (row < tree.getRowCount()) {
    tree.expandRow(row)
    row++
  }
}
fun collapseAll(tree : JTree) {
  var row = tree.getRowCount() - 1
  while (row >= 0) {
    tree.collapseRow(row)
    row--
  }
}
fun main(args: Array<String>) {
  EventQueue.invokeLater {
    JFrame("kotlin swing").apply {
      defaultCloseOperation = JFrame.EXIT_ON_CLOSE
      add(makeUI())
      size = Dimension(320, 240)
      setLocationRelativeTo(null)
      setVisible(true)
    }
  }
}

JCheckBox

  • Smart Cast、キャストでifのネストが深くなるのを避けたい
    • イベント発生元がAbstractButtonなのは自明なのでasを使用する
      • val b = e.getSource() as AbstractButton
    • 以下のような場合は、applyでも回避可能

Java

import java.awt.*;
import javax.swing.*;

public class JCheckBoxExample {
  public JComponent makeUI() {
    JCheckBox cb = new JCheckBox("Always On Top", true);
    cb.addActionListener(e -> {
      AbstractButton b = (AbstractButton) e.getSource();
      Container c = b.getTopLevelAncestor();
      if (c instanceof Window) {
        ((Window) c).setAlwaysOnTop(b.isSelected());
      }
    });
    JPanel p = new JPanel(new BorderLayout());
    p.add(cb, BorderLayout.NORTH);
    return p;
  }
  public static void main(String[] args) {
    EventQueue.invokeLater(() -> {
      JFrame f = new JFrame();
      f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      f.add(new JCheckBoxExample().makeUI());
      f.setSize(320, 240);
      f.setLocationRelativeTo(null);
      f.setVisible(true);
    });
  }
}

Kotlin

import java.awt.*
import javax.swing.*

fun makeUI(): JComponent {
  val cb = JCheckBox("Always On Top", true).apply {
//     addActionListener { e ->
//       val c = e.getSource()
//       if (c is AbstractButton) {
//         val w = c.getTopLevelAncestor()
//         if (w is Window) {
//           w.setAlwaysOnTop(c.isSelected())
//         }
//       }
    addActionListener { e ->
      val b = e.getSource() as AbstractButton
      val w = b.getTopLevelAncestor()
      if (w is Window) {
        w.setAlwaysOnTop(b.isSelected())
      }
    }
//     addActionListener {
//       val w = getTopLevelAncestor()
//       if (w is Window) {
//           w.setAlwaysOnTop(isSelected())
//       }
//     }
  }
  return JPanel(BorderLayout()).apply {
    add(cb, BorderLayout.NORTH)
  }
}

fun main(args: Array<String>) {
  EventQueue.invokeLater {
    JFrame("kotlin swing").apply {
      defaultCloseOperation = JFrame.EXIT_ON_CLOSE
      add(makeUI())
      size = Dimension(320, 240)
      setLocationRelativeTo(null)
      setVisible(true)
    }
  }
}

インターフェイス、匿名内部クラス、throws

  • addTreeWillExpandListener(object: TreeWillExpandListener() { ...と記述するとerror: this class does not have a constructorとエラーになる
  • インターフェイスから匿名内部クラスのインスタンスを生成する場合は()は不要で、addTreeWillExpandListener(object: TreeWillExpandListener { ...と記述する

Java

import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.plaf.IconUIResource;
import javax.swing.tree.*;

public class ThrowsExample {
  public JComponent makeUI() {
    JPanel p = new JPanel(new GridLayout(1, 0, 5, 5));
    p.add(new JScrollPane(new JTree()));
    p.add(new JScrollPane(makeTree()));
    p.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
    return p;
  }
  private static JTree makeTree() {
    Icon icon = new EmptyIcon();
    UIManager.put("Tree.expandedIcon",  new IconUIResource(icon));
    UIManager.put("Tree.collapsedIcon", new IconUIResource(icon));

    JTree tree = new JTree();
    tree.setEditable(true);
    tree.setBorder(BorderFactory.createEmptyBorder(4, 4, 4, 4));
    int row = 0;
    while (row < tree.getRowCount()) {
      tree.expandRow(row++);
    }
    tree.addTreeWillExpandListener(new TreeWillExpandListener() {
      @Override public void treeWillExpand(TreeExpansionEvent e)
          throws ExpandVetoException {
        //throw new ExpandVetoException(e, "Tree expansion cancelled");
      }
      @Override public void treeWillCollapse(TreeExpansionEvent e)
          throws ExpandVetoException {
        throw new ExpandVetoException(e, "Tree collapse cancelled");
      }
    });
    return tree;
  }
  public static void main(String[] args) {
    EventQueue.invokeLater(() -> {
      JFrame f = new JFrame();
      f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
      f.getContentPane().add(new ThrowsExample().makeUI());
      f.setSize(320, 240);
      f.setLocationRelativeTo(null);
      f.setVisible(true);
    });
  }
}

class EmptyIcon implements Icon {
  @Override public void paintIcon(Component c, Graphics g, int x, int y) {
    /* Empty icon */
  }
  @Override public int getIconWidth() {
    return 0;
  }
  @Override public int getIconHeight() {
    return 0;
  }
}

Kotlin

import java.awt.*
import javax.swing.*
import javax.swing.event.*
import javax.swing.plaf.IconUIResource
import javax.swing.tree.*

fun makeUI(): JComponent {
  val emptyIcon = EmptyIcon()
  UIManager.put("Tree.expandedIcon",  IconUIResource(emptyIcon))
  UIManager.put("Tree.collapsedIcon", IconUIResource(emptyIcon))

  val tree = JTree().apply {
    setEditable(true)
    border = BorderFactory.createEmptyBorder(4, 4, 4, 4)
    addTreeWillExpandListener(object: TreeWillExpandListener {
      @Throws(ExpandVetoException::class)
      override fun treeWillExpand(e: TreeExpansionEvent) {
        //throw ExpandVetoException(e, "Tree expansion cancelled")
      }
      @Throws(ExpandVetoException::class)
      override fun treeWillCollapse(e: TreeExpansionEvent) {
        throw ExpandVetoException(e, "Tree collapse cancelled")
      }
    })
  }

  var row = 0;
  while (row < tree.getRowCount()) {
    tree.expandRow(row++);
  }

  return JPanel(GridLayout(1, 0)).apply {
    setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5))
    add(JScrollPane(JTree()))
    add(JScrollPane(tree))
  }
}

class EmptyIcon: Icon {
    override fun paintIcon(c: Component, g: Graphics , x: Int, y: Int) {
      /* Empty icon */
    }
    override fun getIconWidth():  Int = 0
    override fun getIconHeight(): Int = 0
}

fun main(args: Array<String>) {
  EventQueue.invokeLater {
    JFrame("kotlin swing").apply {
      defaultCloseOperation = WindowConstants.EXIT_ON_CLOSE
      add(makeUI())
      size = Dimension(320, 240)
      setLocationRelativeTo(null)
      setVisible(true)
    }
  }
}

Optional

  • Optional#orElse(...)は、let {...} ?: ...に変換
    • Integer stepSize = Optional.ofNullable(stepSizeMap.get(calendarField)).orElse(1);
    • val stepSize = stepSizeMap.get(calendarField).let { it } ?: 1
  • 例えばSpinnerDateModel#getNextValue(...)メソッドをoverride fun getNextValue(): Object = Calendar.getInstance().apply { ...のように変換すると、error: type mismatch: inferred type is Date! but Object was expectedとエラーになる
  • override fun getNextValue(): Any = Calendar.getInstance().apply { ...Anyを使用するようオーバーライドする必要がある
  • Date!は、DateもしくはDate?の意味

Java

import java.awt.*;
import java.text.*;
import java.util.*;
import javax.swing.*;
import javax.swing.text.*;

public class OptionalExample {
  private JComponent makeUI() {
    SimpleDateFormat format = new SimpleDateFormat(
        "mm:ss, SSS", Locale.getDefault());
    DefaultFormatterFactory factory = new DefaultFormatterFactory(
        new DateFormatter(format));

    Calendar calendar = Calendar.getInstance();
    calendar.set(Calendar.HOUR_OF_DAY, 0);
    calendar.clear(Calendar.MINUTE);
    calendar.clear(Calendar.SECOND);
    calendar.clear(Calendar.MILLISECOND);
    Date d = calendar.getTime();

    JSpinner sp1 = new JSpinner(new SpinnerDateModel(
        d, null, null, Calendar.SECOND));
    JSpinner.DefaultEditor ed1 = (JSpinner.DefaultEditor) sp1.getEditor();
    ed1.getTextField().setFormatterFactory(factory);

    HashMap<Integer, Integer> stepSizeMap = new HashMap<>();
    stepSizeMap.put(Calendar.HOUR_OF_DAY, 1);
    stepSizeMap.put(Calendar.MINUTE,      1);
    stepSizeMap.put(Calendar.SECOND,      30);
    stepSizeMap.put(Calendar.MILLISECOND, 500);

    JSpinner sp2 = new JSpinner(new SpinnerDateModel(
        d, null, null, Calendar.SECOND) {
      @Override public Object getPreviousValue() {
        Calendar cal = Calendar.getInstance();
        cal.setTime(getDate());
        Integer calendarField = getCalendarField();
        Integer stepSize = Optional.ofNullable(
            stepSizeMap.get(calendarField)).orElse(1);
        cal.add(calendarField, -stepSize);
        return cal.getTime();
      }
      @Override public Object getNextValue() {
        Calendar cal = Calendar.getInstance();
        cal.setTime(getDate());
        Integer calendarField = getCalendarField();
        Integer stepSize = Optional.ofNullable(
            stepSizeMap.get(calendarField)).orElse(1);
        cal.add(calendarField, stepSize);
        return cal.getTime();
      }
    });
    JSpinner.DefaultEditor ed2 = (JSpinner.DefaultEditor) sp2.getEditor();
    ed2.getTextField().setFormatterFactory(factory);

    JPanel p = new JPanel();
    p.add(sp1);
    p.add(sp2);
    return p;
  }
  public static void main(String... args) {
    EventQueue.invokeLater(() -> {
      JFrame f = new JFrame();
      f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
      f.getContentPane().add(new OptionalExample().makeUI());
      f.setSize(320, 240);
      f.setLocationRelativeTo(null);
      f.setVisible(true);
    });
  }
}

Kotlin

import java.awt.*
import java.text.*
import java.util.*
import javax.swing.*
import javax.swing.text.*

fun makeUI(): JComponent {
  val format = SimpleDateFormat("mm:ss, SSS", Locale.getDefault())
  val factory = DefaultFormatterFactory(DateFormatter(format))

  val calendar = Calendar.getInstance().apply {
    set(Calendar.HOUR_OF_DAY, 0)
    clear(Calendar.MINUTE)
    clear(Calendar.SECOND)
    clear(Calendar.MILLISECOND)
  }
  val d = calendar.getTime()

  val sp1 = JSpinner(SpinnerDateModel(d, null, null, Calendar.SECOND))
  val ed1 = sp1.getEditor()
  if (ed1 is JSpinner.DefaultEditor) {
    ed1.getTextField().setFormatterFactory(factory)
  }

  val stepSizeMap: HashMap<Int, Int> = hashMapOf(
      Calendar.HOUR_OF_DAY to 1,
      Calendar.MINUTE      to 1,
      Calendar.SECOND      to 30,
      Calendar.MILLISECOND to 500)

  val sp2 = JSpinner(object: SpinnerDateModel(d, null, null, Calendar.SECOND) {
    override fun getPreviousValue(): Any = Calendar.getInstance().apply {
      time = getDate()
      val stepSize = stepSizeMap.get(calendarField).let { it } ?: 1
      add(calendarField, -stepSize)
    }.getTime()
    override fun getNextValue(): Any = Calendar.getInstance().apply {
        setTime(getDate())
        val stepSize = stepSizeMap.get(calendarField).let { it } ?: 1
        add(calendarField, stepSize)
    }.getTime()
  })
  val ed2 = sp2.getEditor()
  if (ed2 is JSpinner.DefaultEditor) {
    ed2.getTextField().setFormatterFactory(factory)
  }

  return JPanel().apply {
    add(sp1)
    add(sp2)
  }
}

fun main(args: Array<String>) {
  EventQueue.invokeLater {
    JFrame("kotlin swing").apply {
      defaultCloseOperation = WindowConstants.EXIT_ON_CLOSE
      add(makeUI())
      size = Dimension(320, 240)
      setLocationRelativeTo(null)
      setVisible(true)
    }
  }
}

演算子の優先順位


  • extends, implements
    • IntelliJの自動変換では勝手にopenは付けないようなので、以下のようなエラーが出る場合は、internal class CheckBoxesPanel : JPanel() {open class CheckBoxesPanel : JPanel() {に修正する
      MainPanel.kt:81:37: error: this type is final, so it cannot be inherited from
      internal class CheckBoxesRenderer : CheckBoxesPanel(), TableCellRenderer {
      
  • IntelliJの自動変換ではstatic変数がうまく変換できない?
    • 手動でenum classにして回避
      companion object {
        protected val TITLES = arrayOf("r", "w", "x")
      }
      //...
      MainPanel.kt:45:5: error: property must be initialized or be abstract
          var buttons: Array<JCheckBox>
          ^
      MainPanel.kt:55:19: error: type mismatch: inferred type is Array<JCheckBox?> but Array<JCheckBox> was expected
              buttons = arrayOfNulls<JCheckBox>(TITLES.size)
      

Java

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.plaf.*;
import javax.swing.table.*;

public final class MainPanel {
  public JComponent makeUI() {
    String[] columnNames = {"user", "rwx"};
    Object[][] data = {
      {"owner", 7}, {"group", 6}, {"other", 5}
    };
    TableModel model = new DefaultTableModel(data, columnNames) {
      @Override public Class<?> getColumnClass(int column) {
        return getValueAt(0, column).getClass();
      }
    };
    JTable table = new JTable(model) {
      @Override public void updateUI() {
        super.updateUI();
        getColumnModel().getColumn(1).setCellRenderer(new CheckBoxesRenderer());
        getColumnModel().getColumn(1).setCellEditor(new CheckBoxesEditor());
      }
    };
    table.putClientProperty("terminateEditOnFocusLost", Boolean.TRUE);

    JPanel p = new JPanel(new BorderLayout());
    p.add(new JScrollPane(table));
    return p;
  }
  public static void main(String[] args) {
    EventQueue.invokeLater(() -> {
      JFrame frame = new JFrame();
      frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
      frame.getContentPane().add(new MainPanel().makeUI());
      frame.setSize(320, 240);
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
    });
  }
}

class CheckBoxesPanel extends JPanel {
  protected static final String[] TITLES = {"r", "w", "x"};
  public JCheckBox[] buttons;
  @Override public void updateUI() {
    super.updateUI();
    setOpaque(false);
    setBackground(new Color(0x0, true));
    setLayout(new BoxLayout(this, BoxLayout.X_AXIS));
    initButtons();
  }
  private void initButtons() {
    buttons = new JCheckBox[TITLES.length];
    for (int i = 0; i < buttons.length; i++) {
      JCheckBox b = new JCheckBox(TITLES[i]);
      b.setOpaque(false);
      b.setFocusable(false);
      b.setRolloverEnabled(false);
      b.setBackground(new Color(0x0, true));
      buttons[i] = b;
      add(b);
      add(Box.createHorizontalStrut(5));
    }
  }
  protected void updateButtons(Object v) {
    removeAll();
    initButtons();
    Integer i = v instanceof Integer ? (Integer) v : 0;
    buttons[0].setSelected((i & (1 << 2)) != 0);
    buttons[1].setSelected((i & (1 << 1)) != 0);
    buttons[2].setSelected((i & (1 << 0)) != 0);
  }
}

class CheckBoxesRenderer extends CheckBoxesPanel implements TableCellRenderer {
  @Override public void updateUI() {
    super.updateUI();
    setName("Table.cellRenderer");
  }
  @Override public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
    updateButtons(value);
    return this;
  }
}

class CheckBoxesEditor extends AbstractCellEditor implements TableCellEditor {
  private final CheckBoxesPanel panel = new CheckBoxesPanel() {
    @Override public void updateUI() {
      super.updateUI();
      EventQueue.invokeLater(() -> {
        ActionMap am = getActionMap();
        for (int i = 0; i < buttons.length; i++) {
          String title = TITLES[i];
          am.put(title, new AbstractAction(title) {
            @Override public void actionPerformed(ActionEvent e) {
              Arrays.stream(buttons)
              .filter(b -> b.getText().equals(title))
              .findFirst()
              .ifPresent(JCheckBox::doClick);
              fireEditingStopped();
            }
          });
        }
        InputMap im = getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_R, 0), TITLES[0]);
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_W, 0), TITLES[1]);
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_X, 0), TITLES[2]);
      });
    }
  };
  @Override public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column) {
    panel.updateButtons(value);
    return panel;
  }
  @Override public Object getCellEditorValue() {
    int i = 0;
    i = panel.buttons[0].isSelected() ? 1 << 2 | i : i;
    i = panel.buttons[1].isSelected() ? 1 << 1 | i : i;
    i = panel.buttons[2].isSelected() ? 1 << 0 | i : i;
    return i;
  }
}

Kotlin

import java.awt.*
import java.awt.event.*
import java.util.*
import javax.swing.*
import javax.swing.event.*
import javax.swing.plaf.*
import javax.swing.table.*

fun makeUI(): JComponent {
  val columnNames = arrayOf("user", "rwx")
  val data = arrayOf(arrayOf<Any>("owner", 7), arrayOf<Any>("group", 6), arrayOf<Any>("other", 5))
  val model = object : DefaultTableModel(data, columnNames) {
    override fun getColumnClass(column: Int): Class<*> {
      return getValueAt(0, column).javaClass
    }
  }
  val table = object : JTable(model) {
    override fun updateUI() {
      super.updateUI()
      getColumnModel().getColumn(1).setCellRenderer(CheckBoxesRenderer())
      getColumnModel().getColumn(1).setCellEditor(CheckBoxesEditor())
    }
  }
  table.putClientProperty("terminateEditOnFocusLost", java.lang.Boolean.TRUE)
  return JPanel(BorderLayout(5, 5)).apply {
    add(JScrollPane(table))
  }
}

fun main(args: Array<String>) {
  EventQueue.invokeLater {
    JFrame("kotlin swing").apply {
      defaultCloseOperation = JFrame.EXIT_ON_CLOSE
      add(makeUI())
      size = Dimension(320, 240)
      setLocationRelativeTo(null)
      setVisible(true)
    }
  }
}

open class CheckBoxesPanel() : JPanel() {
  public val buttons = arrayOf(JCheckBox(Permission.READ.toString()), JCheckBox(Permission.WRITE.toString()), JCheckBox(Permission.EXECUTE.toString()))

  override fun updateUI() {
    super.updateUI()
    setOpaque(false)
    setBackground(Color(0x0, true))
    setLayout(BoxLayout(this, BoxLayout.X_AXIS))
    EventQueue.invokeLater({ initButtons() })
  }

  private fun initButtons() {
    for (b in buttons) {
      b.setOpaque(false)
      b.setFocusable(false)
      b.setRolloverEnabled(false)
      b.setBackground(Color(0x0, true))
      add(b)
      add(Box.createHorizontalStrut(5))
    }
  }

  public fun updateButtons(v: Any) {
    removeAll()
    initButtons()
    val i = v as ? Int ? : 0
    buttons[0].setSelected(i and (1 shl 2) != 0)
    buttons[1].setSelected(i and (1 shl 1) != 0)
    buttons[2].setSelected(i and (1 shl 0) != 0)
  }
}

enum class Permission(var str: String) {
  READ("r"), WRITE("w"), EXECUTE("x");
  override fun toString() = str
}

internal class CheckBoxesRenderer : CheckBoxesPanel(), TableCellRenderer {
  override fun updateUI() {
    super.updateUI()
    setName("Table.cellRenderer")
  }
  override fun getTableCellRendererComponent(table: JTable, value: Any, isSelected: Boolean, hasFocus: Boolean, row: Int, column: Int): Component {
    updateButtons(value)
    return this
  }
}

internal class CheckBoxesEditor : AbstractCellEditor(), TableCellEditor {
  private val panel = object : CheckBoxesPanel() {
    override fun updateUI() {
      super.updateUI()
      EventQueue.invokeLater({
        val am = getActionMap()
        for (i in buttons.indices) {
          val title = buttons[i].getText()
          am.put(title, object : AbstractAction(title) {
            override fun actionPerformed(e: ActionEvent) {
              Arrays.stream(buttons)
                .filter({ b -> b.getText() == title })
                .findFirst()
                .ifPresent({ it.doClick() })
              fireEditingStopped()
            }
          })
        }
        val im = getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW)
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_R, 0), Permission.READ.toString())
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_W, 0), Permission.WRITE.toString())
        im.put(KeyStroke.getKeyStroke(KeyEvent.VK_X, 0), Permission.EXECUTE.toString())
      })
    }
  }

  override fun getTableCellEditorComponent(table: JTable, value: Any, isSelected: Boolean, row: Int, column: Int): Component {
    panel.updateButtons(value)
    return panel
  }

  override fun getCellEditorValue(): Any {
    var i = 0
    i = if (panel.buttons[0].isSelected()) 1 shl 2 or i else i
    i = if (panel.buttons[1].isSelected()) 1 shl 1 or i else i
    i = if (panel.buttons[2].isSelected()) 1 shl 0 or i else i
    return i
  }
}

Arrays.asList(...)

  • IntelliJの自動変換ではArrays.asList(...)の型パラメータを自動的に変換してくれない
    • Arrays.<Component>asList(...)と型パラメータを明示しても省略される
    • for (c in Arrays.asList(...)) {に変換されてerror: none of the following functions can be called with the arguments supplied:になる
    • for (c: Component in Arrays.asList<Component>(...)) {、またはfor (c in listOf<Component>(...)) {などに手動で修正(for (c: Component in Arrays<Component>.asList(...)) {も可能?)
  • 型引数
    • JavaKotlinでは型引数を付ける位置が異なるので注意
  • KotlinJava風にfor (c in Arrays.<Component>asList(...)) {を使用すると、hello.kt:97:26: error: expecting an elementとエラーになる

Java

Box box = Box.createVerticalBox();
for (Component c: Arrays.<Component>asList(textField1, textField2, combo3, combo4)) {
  box.add(c);
  box.add(Box.createVerticalStrut(5));
}
// for (Component c: Arrays.asList(...)) { でも同じ変換結果になる

Kotlin(自動変換)

val box = Box.createVerticalBox()
for (c in Arrays.asList(textField1, textField2, combo3, combo4)) {
  box.add(c)
  box.add(Box.createVerticalStrut(5))
}
// hello.kt:100:17: error: none of the following functions can be called with the arguments supplied:
// public open fun add(p0: Component!): Component! defined in javax.swing.Box
// public open fun add(p0: PopupMenu!): Unit defined in javax.swing.Box
//             box.add(c)
//                 ^

Kotlin(手動修正)

val box = Box.createVerticalBox()
for (c in Arrays.asList<Component>(textField1, textField2, combo3, combo4)) {
  box.add(c);
  box.add(Box.createVerticalStrut(5));
}
// or:
// for (c in listOf<Component>(textField1, textField2, combo3, combo4)) {
// for (c in Arrays<Component>.asList(textField1, textField2, combo3, combo4)) {

JTree, ActionListener

  • IntelliJの自動変換ではActionListenerなどの関数型インターフェースのラムダ式をうまく変換できない場合がある
    • AbstractCellEditor#stopCellEditing()booleanを返すのでerror: type mismatch: inferred type is (???) -> Boolean but ActionListener? was expectedとエラーになる
  • SAM Conversions - Calling Java from Kotlin - Kotlin Programming Language

Java

protected ActionListener handler;
//...
handler = e -> stopCellEditing();

Kotlin(自動変換)

protected var handler: ActionListener? = null
//...
handler = { e -> stopCellEditing() }
// error: type mismatch: inferred type is (???) -> Boolean but ActionListener? was expected
//             handler = { e -> stopCellEditing() }
// error: cannot infer a type for this parameter. Please specify it explicitly.
//             handler = { e -> stopCellEditing() }
// error: modifier 'override' is not applicable to 'local function'
//               override fun actionPerformed(e: ActionEvent) : Unit {

Kotlin(手動修正)

protected var handler: ActionListener? = null
//...
handler = ActionListener { stopCellEditing() }
// or:
handler = object: ActionListener {
  override fun actionPerformed(e: ActionEvent) : Unit { // Unitは無くても可
    stopCellEditing()
  }
}
  • IntelliJの自動変換で、以下のようなエラーになる場合は、ObjectAnyに手動変換する
    error: class 'CheckBoxNodeRenderer' is not abstract and does not implement abstract member public abstract fun getTreeCellRendererComponent(p0: JTree!, p1: Any!, p2: Boolean, p3: Boolean, p4: Boolean, p5: Int, p6: Boolean): Component! defined in javax.swing.tree.TreeCellRenderer
    internal class CheckBoxNodeRenderer : TreeCellRenderer {
  • getterのみオーバーライド

Java

class CheckBoxNodeEditor extends AbstractCellEditor implements TreeCellEditor {
  @Override public Object getCellEditorValue() {
    return new CheckBoxNode(checkBox.getText(), checkBox.isSelected());
  }
  //...

Kotlin(自動変換)

val cellEditorValue: Any
  override get() = CheckBoxNode(checkBox.getText(), checkBox.isSelected())
//error: modifier 'override' is not applicable to 'getter'
//       override get() = CheckBoxNode(checkBox.getText(), checkBox.isSelected())

Kotlin(手動修正)

  override fun getCellEditorValue(): Any {
    return CheckBoxNode(checkBox.getText(), checkBox.isSelected())
  }

Java

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.tree.*;

public class LeafCheckBoxTreeTest {
  private JComponent makeUI() {
    JTree tree = new JTree();
    tree.setEditable(true);
    tree.setCellRenderer(new CheckBoxNodeRenderer());
    tree.setCellEditor(new CheckBoxNodeEditor());
    tree.setRowHeight(18);

    boolean b = true;
    TreeModel model = tree.getModel();
    DefaultMutableTreeNode root = (DefaultMutableTreeNode) model.getRoot();
    Enumeration<?> e = root.breadthFirstEnumeration();
    while (e.hasMoreElements()) {
      DefaultMutableTreeNode node = (DefaultMutableTreeNode) e.nextElement();
      String s = Objects.toString(node.getUserObject(), "");
      node.setUserObject(new CheckBoxNode(s, b));
      b ^= true;
    }
    return new JScrollPane(tree);
  }
  public static void main(String[] args) {
    EventQueue.invokeLater(() -> {
      UIManager.put("swing.boldMetal", Boolean.FALSE);
      JFrame f = new JFrame();
      f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
      f.getContentPane().add(new LeafCheckBoxTreeTest().makeUI());
      f.setSize(320, 240);
      f.setLocationRelativeTo(null);
      f.setVisible(true);
    });
  }
}

class CheckBoxNodeRenderer implements TreeCellRenderer {
  private final JCheckBox checkBox = new JCheckBox();
  private final DefaultTreeCellRenderer renderer = new DefaultTreeCellRenderer();
  @Override public Component getTreeCellRendererComponent(
      JTree tree, Object value, boolean selected, boolean expanded,
      boolean leaf, int row, boolean hasFocus) {
    if (leaf && value instanceof DefaultMutableTreeNode) {
      checkBox.setEnabled(tree.isEnabled());
      checkBox.setFont(tree.getFont());
      checkBox.setOpaque(false);
      checkBox.setFocusable(false);
      Object userObject = ((DefaultMutableTreeNode) value).getUserObject();
      if (userObject instanceof CheckBoxNode) {
        CheckBoxNode node = (CheckBoxNode) userObject;
        checkBox.setText(node.text);
        checkBox.setSelected(node.selected);
      }
      return checkBox;
    }
    return renderer.getTreeCellRendererComponent(
        tree, value, selected, expanded, leaf, row, hasFocus);
  }
}

class CheckBoxNodeEditor extends AbstractCellEditor implements TreeCellEditor {
  private final JCheckBox checkBox = new JCheckBox() {
    protected transient ActionListener handler;
    @Override public void updateUI() {
      removeActionListener(handler);
      super.updateUI();
      setOpaque(false);
      setFocusable(false);
      handler = e -> stopCellEditing();
      addActionListener(handler);
    }
  };
  @Override public Component getTreeCellEditorComponent(
      JTree tree, Object value, boolean selected, boolean expanded,
      boolean leaf, int row) {
    if (leaf && value instanceof DefaultMutableTreeNode) {
      Object userObject = ((DefaultMutableTreeNode) value).getUserObject();
      if (userObject instanceof CheckBoxNode) {
        checkBox.setSelected(((CheckBoxNode) userObject).selected);
      } else {
        checkBox.setSelected(false);
      }
      checkBox.setText(value.toString());
    }
    return checkBox;
  }
  @Override public Object getCellEditorValue() {
    return new CheckBoxNode(checkBox.getText(), checkBox.isSelected());
  }
  @Override public boolean isCellEditable(EventObject e) {
    if (e instanceof MouseEvent && e.getSource() instanceof JTree) {
      MouseEvent me = (MouseEvent) e;
      JTree tree = (JTree) me.getComponent();
      TreePath path = tree.getPathForLocation(me.getX(), me.getY());
      Object o = path.getLastPathComponent();
      if (o instanceof TreeNode) {
        return ((TreeNode) o).isLeaf();
      }
    }
    return false;
  }
}

class CheckBoxNode {
  public final String text;
  public final boolean selected;
  protected CheckBoxNode(String text, boolean selected) {
    this.text = text;
    this.selected = selected;
  }
  @Override public String toString() {
    return text;
  }
}

Kotlin

import java.awt.*
import java.awt.event.*
import java.util.*
import javax.swing.*
import javax.swing.event.*
import javax.swing.tree.*

private fun makeUI(): JComponent {
  val tree = JTree()
  tree.setEditable(true)
  tree.setCellRenderer(CheckBoxNodeRenderer())
  tree.setCellEditor(CheckBoxNodeEditor())
  tree.setRowHeight(18)

  var b = true
  val model = tree.getModel()
  val root = model.getRoot() as DefaultMutableTreeNode
  val e = root.breadthFirstEnumeration()
  while (e.hasMoreElements()) {
    val node = e.nextElement() as DefaultMutableTreeNode
    val s = Objects.toString(node.getUserObject(), "")
    node.setUserObject(CheckBoxNode(s, b))
    b = b xor true
  }
  return JScrollPane(tree)
}

fun main(args: Array<String>) {
  EventQueue.invokeLater {
    UIManager.put("swing.boldMetal", false)
    JFrame("kotlin swing").apply {
      defaultCloseOperation = JFrame.EXIT_ON_CLOSE
      add(makeUI())
      size = Dimension(320, 240)
      setLocationRelativeTo(null)
      setVisible(true)
    }
  }
}

internal class CheckBoxNodeRenderer : TreeCellRenderer {
  private val checkBox = JCheckBox()
  private val renderer = DefaultTreeCellRenderer()
  override fun getTreeCellRendererComponent(
    tree: JTree, value: Any, selected: Boolean, expanded: Boolean,
    leaf: Boolean, row: Int, hasFocus: Boolean): Component {
    if (leaf && value is DefaultMutableTreeNode) {
      checkBox.setEnabled(tree.isEnabled())
      checkBox.setFont(tree.getFont())
      checkBox.setOpaque(false)
      checkBox.setFocusable(false)
      val userObject = value.getUserObject()
      if (userObject is CheckBoxNode) {
        val node = userObject // as CheckBoxNode
        checkBox.setText(node.text)
        checkBox.setSelected(node.selected)
      }
      return checkBox
    }
    return renderer.getTreeCellRendererComponent(
      tree, value, selected, expanded, leaf, row, hasFocus)
  }
}

internal class CheckBoxNodeEditor : AbstractCellEditor(), TreeCellEditor {
  private val checkBox = object : JCheckBox() {
    protected var handler: ActionListener? = null
    override fun updateUI() {
      removeActionListener(handler)
      super.updateUI()
      setOpaque(false)
      setFocusable(false)
      // handler = object: ActionListener {
      //   override fun actionPerformed(e: ActionEvent) : Unit {
      //     stopCellEditing()
      //   }
      // }
      handler = ActionListener { stopCellEditing() }
      addActionListener(handler)
    }
  }

  override fun getTreeCellEditorComponent(
      tree: JTree, value: Any, selected: Boolean, expanded: Boolean,
      leaf: Boolean, row: Int): Component {
    if (leaf && value is DefaultMutableTreeNode) {
      val userObject = value.getUserObject()
      if (userObject is CheckBoxNode) {
        checkBox.setSelected(userObject.selected)
      } else {
        checkBox.setSelected(false)
      }
      checkBox.setText(value.toString())
    }
    return checkBox
  }

  override fun getCellEditorValue(): Any {
    return CheckBoxNode(checkBox.getText(), checkBox.isSelected())
  }

  override fun isCellEditable(e: EventObject): Boolean {
    if (e is MouseEvent && e.getSource() is JTree) {
      val tree = e.getComponent() as JTree
      val path = tree.getPathForLocation(e.getX(), e.getY())
      val o = path.getLastPathComponent()
      if (o is TreeNode) {
        return o.isLeaf()
      }
    }
    return false
  }
}

internal class CheckBoxNode public constructor(val text: String, val selected: Boolean) {
  override fun toString(): String {
    return text
  }
}

メソッド参照

  • IntelliJの自動変換ではメソッド参照の変換が苦手?

Java

public static Stream<TreeNode> children(TreeNode node) {
  Class<TreeNode> clz = TreeNode.class;
  return Collections.list((Enumeration<?>) node.children())
    .stream().filter(clz::isInstance).map(clz::cast);
}

Kotlin(自動変換)

fun children(node: TreeNode): Stream<TreeNode> {
  val clz = TreeNode::class.java
  return Collections.list(node.children() as Enumeration<*>)
    .stream().filter(???({ clz!!.isInstance() })).map(clz!!.cast)
}

Kotlin(手動修正)

fun children(node: TreeNode): Stream<TreeNode> {
  val clz = TreeNode::class.java
  return Collections.list(node.children() as Enumeration<*>)
    .stream().filter(clz::isInstance).map(clz::cast)
    // .filterIsInstance(clz).stream()
}

Kotlin(手動修正): filterIsInstanceが便利

fun children(node: TreeNode): List<TreeNode> {
  return (node.children() as Enumeration<*>)
    .toList().filterIsInstance(TreeNode::class.java)
}
  • Container#add(Component)メソッドは戻り値としてComponentを返す
    • Javaの場合、終端処理のforEach(p::add)では戻り値を無視してContainer#add(Component)をメソッド参照することが可能
    • Kotlinの場合、forEach(p::add)とすると、addメソッドで引数がComponent!、戻り値がUnitになるメソッドを探すためメソッド参照で以下のようなエラーになる
hello.kt:38:66: error: none of the following functions can be called with the arguments supplied:
public open fun add(p0: Component!): Component! defined in javax.swing.JPanel
public open fun add(p0: Component!, p1: Any!): Unit defined in javax.swing.JPanel
public open fun add(p0: Component!, p1: Any!, p2: Int): Unit defined in javax.swing.JPanel
public open fun add(p0: Component!, p1: Int): Component! defined in javax.swing.JPanel
public open fun add(p0: PopupMenu!): Unit defined in javax.swing.JPanel
public open fun add(p0: String!, p1: Component!): Component! defined in javax.swing.JPanel
    listOf(button1, button2, button3, button4).forEach(p::add)
                                                          ^

Java

JPanel p = new JPanel(new GridLayout(0, 1, 2, 2));
Arrays.asList(button1, button2).forEach(p::add);

Kotlin(自動変換)

val p = JPanel(GridLayout(0, 1, 2, 2))
Arrays.asList(button1, button2).forEach( ?? ? ({ p.add() }))

Kotlin(手動修正)

val p = JPanel(GridLayout(0, 1, 2, 2))
listOf(button1, button2).forEach({ b -> p.add(b) })
//or listOf(button1, button2).map(p::add)

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