“Unexpected change in background of header of custom JComboBox in Swing”

huangapple
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英文:

Unexpected change in background of header of custome jcombobox in swing

问题

我尝试为我的菜单侧边栏创建一个自定义的下拉框（jcombobox）。
我的下拉框中的项是JButton，因为我发现这样更容易插入和对齐图标和文本。
但我的问题是，当我选择一个下拉项时，标题的颜色意外地更改为组件的默认颜色。

  1. public class MyComboBoxRenderer extends JLabel implements ListCellRenderer<Object> {
  2. 	private String _title;
  3. 	private JButton header;
  4. 	public MyComboBoxRenderer(String title) {
  5. 		_title = title;
  6. 	}
  8. 	@Override
  9. 	public Component getListCellRendererComponent(JList<?> list, Object value,
  10. 			int index, boolean isSelected, boolean hasFocus) {
  11. 		JButton item = new JButton();
  12. 		item.setOpaque(true);
  13. 		item.setBorderPainted(false);
  14. 		item.setFocusPainted(false);
  15. 		item.setBackground(isSelected ? Frame.LIGHTER_COLOR : Frame.LIGHT_COLOR ); 
  16. 		ImageIcon dot = new ImageIcon("image/icon/orange_dot.png");
  17. 		if (index == -1){
  18. 			item.setText(_title);
  19. 			header=item;
  20. 			return item; 
  21. 		}
  22. 		else{
  23. 			item.setIcon(dot);
  24. 			item.setIconTextGap(30);
  25. 			item.setText(value.toString());
  26. 			return item;
  27. 		}
  28. 		
  29. 	}
  30. 	
  31. 	public JButton getHeader(){
  32. 		return header;
  33. 	}
  34. }
  1. public static class MyComboBoxUI extends BasicComboBoxUI {
  2. 	final JButton button = new JButton(EXPAND_ARROW);
  4. 	protected void installDefaults() {
  5. 		super.installDefaults();
  6. 	}
  8. 	@Override
  9. 	protected JButton createArrowButton() {
  10. 		button.setContentAreaFilled(false);
  11. 		button.setBorder(null);
  12. 		return button;
  13. 	}
  15. 	@Override
  16. 	public void configureArrowButton() {
  17. 		super.configureArrowButton();
  18. 	}
  20. 	public JButton getArrowButton(){
  21. 		return button;
  22. 	}
  23. }
  1. public class ComboBox extends JComboBox {
  2. 	public boolean isExpanded = false;
  3. 	private MyComboBoxRenderer renderer;
  4. 	public ComboBox() {
  5. 		super();
  6. 		this.setUI(new MyComboBoxUI());
  7. 	}
  8. 	public ComboBox(String[] list) {
  9. 		super(list);
  10. 		renderer = new MyComboBoxRenderer("Lists Of Vocab");
  11. 		this.setUI(new MyComboBoxUI());
  12. 		this.setFont(Frame.I_FONT);
  13. 		this.setForeground(Frame.FONT_COLOR);
  14. 		this.setBackground(Frame.LIGHT_COLOR);
  15. 		this.setRenderer(renderer);
  16. 		MyComboBoxUI ui = (MyComboBoxUI) this.getUI();
  17. 		JButton arrowButton = ui.getArrowButton();
  18. 		arrowButton.addActionListener((ActionEvent e) -> {
  19. 			isExpanded = !isExpanded;
  20. 			if(isExpanded == true){
  21. 				arrowButton.setIcon(COLLAPSE_ARROW);
  22. 			}
  23. 			else{
  24. 				arrowButton.setIcon(EXPAND_ARROW);
  25. 			}
  26. 		});
  27. 	}
  28. 	public MyComboBoxRenderer getRenderer(){
  29. 		return renderer;
  30. 	}
  31. }

我将这个下拉框添加到了侧边栏中：

  1. private void addCheckBoxToSideBar(){
  2. 	ComboBox lists = new ComboBox(listNames);
  3. 	lists.setAlignmentX(Component.LEFT_ALIGNMENT); // 必须设置
  4. 	lists.addItemListener(new ItemListener(){
  5. 		@Override
  6. 		public void itemStateChanged(ItemEvent e) {
  7. 			if (e.getStateChange() == ItemEvent.SELECTED) {
  8. 				CardLayout cl = (CardLayout)(mainPane.getLayout());
  9. 				cl.show(mainPane, (String)e.getItem());
  10. 			}
  11. 		}
  12. 	});
  14. 	sideBar.add(lists);
  15. }

这是初始状态：

初始状态图片

但当我点击选择一个项时，它会变成默认颜色：

选择项后图片

以下是我尝试但未成功的方法：

  • 在itemStateChanged中设置标题的背景颜色
  • 获取BasicComboBoxEditor的JTextfield

我想知道是否更新UI引起了这个问题，但我对此不太了解。

英文:

I try to make a custom jcombobox for my menu sidebar
my jcombobox has JButton as items because I found it easy to insert and align icon and text.
But my problem is when I choose a item in dropdown, the color of the header changes unexpectedly to the default color of component.

  1. public class MyComboBoxRenderer extends JLabel implements ListCellRenderer&lt;Object&gt; {
  2. 	private String _title;
  3. 	private JButton header;
  4. 	public MyComboBoxRenderer(String title) {
  5. 		_title = title;
  6. 	}
  8. 	@Override
  9. 	public Component getListCellRendererComponent(JList&lt;?&gt; list, Object value,
  10. 			int index, boolean isSelected, boolean hasFocus) {
  11. 		JButton item = new JButton();
  12. 		item.setOpaque(true);
  13. 		item.setBorderPainted(false);
  14. 		item.setFocusPainted(false);
  15. 		item.setBackground(isSelected ? Frame.LIGHTER_COLOR : Frame.LIGHT_COLOR ); 
  16. 		ImageIcon dot = new ImageIcon(&quot;image/icon/orange_dot.png&quot;);
  17. 		if (index == -1){
  18. 			item.setText(_title);
  19. 			header=item;
  20. 			return item; 
  21. 		}
  22. 		else{
  23. 			item.setIcon(dot);
  24. 			item.setIconTextGap(30);
  25. 			item.setText(value.toString());
  26. 			return item;
  27. 		}
  28. 		
  29. 	}
  30. 	
  31. 	public JButton getHeader(){
  32. 		return header;
  33. 	}
  34. }
  1. public static class MyComboBoxUI extends BasicComboBoxUI {
  2. 		final JButton button= new JButton(EXPAND_ARROW);
  3.         protected void installDefaults() {
  4.             super.installDefaults();
  5.         }
  7.         @Override
  8.         protected JButton createArrowButton() {
  9.             button.setContentAreaFilled(false);
  10.             button.setBorder(null);
  11.             return button;
  12.         }
  14.         @Override
  15.         public void configureArrowButton() {
  16.             super.configureArrowButton();
  17.         }
  18.         
  19.         public JButton getArrowButton(){
  20. 			return button;
  21. 		}
  22. 	}
  1. public class ComboBox extends JComboBox{
  2. 	public boolean isExpanded = false;
  3. 	private MyComboBoxRenderer renderer;
  4. 	public ComboBox(){
  5. 		super();
  6. 		this.setUI(new MyComboBoxUI());
  7. 	}
  8. 	public ComboBox(String[] list){
  9. 		super(list);
  10. 		renderer = new MyComboBoxRenderer(&quot;Lists Of Vocab&quot;);
  11. 		this.setUI(new MyComboBoxUI());
  12. 		this.setFont(Frame.I_FONT);
  13. 		this.setForeground(Frame.FONT_COLOR);
  14. 		this.setBackground(Frame.LIGHT_COLOR);
  15. 		this.setRenderer(renderer);
  16. 		MyComboBoxUI ui = (MyComboBoxUI) this.getUI();
  17. 		JButton arrowButton = ui.getArrowButton();
  18. 		arrowButton.addActionListener((ActionEvent e)-&gt;{
  19. 			isExpanded = !isExpanded;
  20. 			if(isExpanded == true){
  21. 				arrowButton.setIcon(COLLAPSE_ARROW);
  22. 			}
  23. 			else{
  24. 				arrowButton.setIcon(EXPAND_ARROW);
  25. 			}
  26. 		});
  27. 	}
  28. 	public MyComboBoxRenderer getRenderer(){
  29. 		return renderer;
  30. 	}

I add this combobox to the sideBar

  1.     private void addCheckBoxToSideBar(){
  2.     	ComboBox lists = new ComboBox(listNames);
  3.     	lists.setAlignmentX(Component.LEFT_ALIGNMENT); // have to have
  4.     	lists.addItemListener(new ItemListener(){
  5. 			@Override
  6.             public void itemStateChanged(ItemEvent e) {
  7.             if (e.getStateChange() == ItemEvent.SELECTED) {
  8.             	CardLayout cl = (CardLayout)(mainPane.getLayout());
  9.                 cl.show(mainPane, (String)e.getItem());[enter image description here][1]
  10.             }
  11.         }
  12.     });
  14.     	sideBar.add(lists);
  15.     }

This is first:

https://i.stack.imgur.com/ctVnT.png

But when I click to choose an item, it changes to default color:

https://i.stack.imgur.com/KkhhO.png

Those are what I tried but they didn't work:

  • to set the background of the header in the itemStateChanged
  • get the JTextfield of BasicComboBoxEditor of it

I wonder whether updating UI causes this problem but I don't understand much about it.

答案1

得分: 0

在你的 MyComboBoxUI 中，尝试覆盖这个方法：

  1. @Override
  2. public void paintCurrentValueBackground(Graphics g, Rectangle bounds, boolean hasFocus) {
  3.     Color t = g.getColor();
  4.     g.setColor(your_color);
  5.     g.fillRect(bounds.x, bounds.y, bounds.width, bounds.height);
  6.     g.setColor(t);
  7. }
英文:

In your MyComboBoxUI, try overriding this method :

  1. @Override
  2. public void paintCurrentValueBackground(Graphics g,Rectangle bounds,boolean hasFocus)
  3. {
  4.  Color t = g.getColor();
  5.  g.setColor(your_color);
  6.  g.fillRect(bounds.x,bounds.y,bounds.width,bounds.height);
  7.  g.setColor(t);
  8. }

huangapple
  • 本文由 发表于 2020年8月1日 11:28:44
  • 转载请务必保留本文链接：https://go.coder-hub.com/63201468.html
  • background
  • java
  • jbutton
  • jcombobox
  • swing
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