Swing/RoundedDropDownList の変更点

---
category: swing
folder: RoundedDropDownList
title: JComboBoxのドロップダウンリストに角丸のBorderを設定する
tags: [JComboBox, BasicComboPopup, JPopupMenu, Border]
author: aterai
pubdate: 2016-01-11T00:02:17+09:00
description: JComboBoxからBasicComboPopupを取得し、これに角丸のBorderを設定します。
image: https://lh3.googleusercontent.com/-hO6OrwNE6O4/VpJu21j7FbI/AAAAAAAAOLA/mUBgzYUJpes/s800-Ic42/RoundedDropDownList.png
---
* Summary [#summary]
`JComboBox`から`BasicComboPopup`を取得し、これに角丸の`Border`を設定します。

#download(https://lh3.googleusercontent.com/-hO6OrwNE6O4/VpJu21j7FbI/AAAAAAAAOLA/mUBgzYUJpes/s800-Ic42/RoundedDropDownList.png)

* Source Code Examples [#sourcecode]
#code(link){{
JComboBox<String> combo1 = new JComboBox<String>(makeModel()) {
  private transient PopupMenuListener listener;
  @Override public void updateUI() {
    removePopupMenuListener(listener);
    UIManager.put("ComboBox.border", new RoundedCornerBorder());
    super.updateUI();
    setUI(new BasicComboBoxUI());
    listener = new HeavyWeightContainerListener();
    addPopupMenuListener(listener);
    Object o = getAccessibleContext().getAccessibleChild(0);
    if (o instanceof JComponent) {
      JComponent c = (JComponent) o;
      c.setBorder(new RoundedCornerBorder());
      c.setForeground(FOREGROUND);
      c.setBackground(BACKGROUND);
    }
  }
};
}}

* Description [#explanation]
* Description [#description]
- 上:
-- `UIManager.put(...)`で`JComboBox`の背景色などを変更して`BasicComboBoxUI`を設定
- 中:
-- 上の`JComboBox`から`getAccessibleContext().getAccessibleChild(0)`で`BasicComboPopup`を取得し角丸の`Border`を設定
-- `JComboBox`に`PopupMenuListener`を追加しドロップダウンリストが`JFrame`の外側にはみ出す(`HeavyWeightContainer`の`JWindow`に`JPopupMenu`が配置されている)場合は、`JWindow`の背景を透明化して角丸部分を非表示に設定
- 下:
-- 中の`JComboBox`と同様に`BasicComboPopup`を取得して下辺のみ角丸の`Border`を設定
--- `JComboBox`自体には上辺のみ角丸の`Border`を設定
-- `ArrowButton`を変更

* Reference [#reference]
- [[JComboBoxの角を丸める>Swing/RoundedComboBox]]
- [https://stackoverflow.com/questions/34503780/rounded-corner-for-jcombobox/34534091#34534091 java - Rounded Corner for JComboBox - Stack Overflow]

* Comment [#comment]
#comment
#comment