正如您所注意到的,没有公共 api 可以访问 DefaultSwatchChooserPanel 中的最近颜色,即使面板本身也无法访问。
因为您需要一些逻辑/bean 来保存和重置最近的颜色(加上扩展的鼠标交互),所以滚动您自己的方式是要走的路。有关一些指导,请查看样本面板的实现(咳嗽...... c&p 你需要什么并修改你不需要的)。基本上,像
// a bean that keeps track of the colors
public static class ColorTracker extends AbstractBean {
private List<Color> colors = new ArrayList<>();
public void addColor(Color color) {
List<Color> old = getColors();
colors.add(0, color);
firePropertyChange("colors", old, getColors());
}
public void setColors(List<Color> colors) {
List<Color> old = getColors();
this.colors = new ArrayList<>(colors);
firePropertyChange("colors", old, getColors());
}
public List<Color> getColors() {
return new ArrayList<>(colors);
}
}
// a custom SwatchChooserPanel which takes and listens to the tracker changes
public class MySwatchChooserPanel ... {
ColorTracker tracker;
public void setColorTracker(....) {
// uninstall old tracker
....
// install new tracker
this.tracker = tracker;
if (tracker != null)
tracker.addPropertyChangeListener(.... );
updateRecentSwatchPanel()
}
/**
* A method updating the recent colors in the swatchPanel
* This is called whenever necessary, specifically after building the panel,
* on changes of the tracker, from the mouseListener
*/
protected void updateRecentSwatchPanel() {
if (recentSwatchPanel == null) return;
recentSwatchPanel.setMostRecentColors(tracker != null ? tracker.getColors() : null);
}
// the mouseListener which updates the tracker and triggers the doubleClickAction
// if available
class MainSwatchListener extends MouseAdapter implements Serializable {
@Override
public void mousePressed(MouseEvent e) {
if (!isEnabled())
return;
if (e.getClickCount() == 2) {
handleDoubleClick(e);
return;
}
Color color = swatchPanel.getColorForLocation(e.getX(), e.getY());
setSelectedColor(color);
if (tracker != null) {
tracker.addColor(color);
} else {
recentSwatchPanel.setMostRecentColor(color);
}
}
/**
* @param e
*/
private void handleDoubleClick(MouseEvent e) {
if (action != null) {
action.actionPerformed(null);
}
}
}
}
// client code can install the custom panel on a JFileChooser, passing in a tracker
private JColorChooser createChooser(ColorTracker tracker) {
JColorChooser chooser = new JColorChooser();
List<AbstractColorChooserPanel> choosers =
new ArrayList<>(Arrays.asList(chooser.getChooserPanels()));
choosers.remove(0);
MySwatchChooserPanel swatch = new MySwatchChooserPanel();
swatch.setColorTracker(tracker);
swatch.setAction(doubleClickAction);
choosers.add(0, swatch);
chooser.setChooserPanels(choosers.toArray(new AbstractColorChooserPanel[0]));
return chooser;
}
至于 doubleClick 处理:增强 swatchChooser 以执行操作并根据需要从 mouseListener 调用该操作。