我有一个扩展 JPanel 的类（时间轴）。时间轴面板包含许多手动定位的 JLabel（绿色和橙色元素）（“null-Layout”）。时间轴顶部是一些用于在月份之间切换的按钮。有时当我在月份之间切换时，swing 不会绘制 JLabels，但总是绘制网格背景。
我已经尝试过许多“神奇”的方法（重绘、重新验证、无效、验证、updateUI）。
成功绘制时间轴：
失败的绘画：
一个简短的例子：
public interface IDateSelectorRegistrar {
void addListener(DateSelectorListener listener);
void removeListener(DateSelectorListener listener);
}
public interface DateSelectorListener {
void dateChanged(Timestamp from, Timestamp to);
}
public interface ITimelineModel {
Timespan[] getTimespans(Timestamp from, Timestamp to);
}
public class Timespan {
private String title;
private Timestamp to;
private Timestamp from;
public Timespan(String title, Timestamp from, Timestamp to) {
this.title = title;
this.from = from;
this.to = to;
}
// setters and getters
}
public class TimelineLabel extends JLabel {
public TimelineLabel(Timespan timespan) {
super(timespan.getTitle());
}
@Override
protected void paintComponent(Graphics g) {
// paint colored background
super.paintComponent(g);
}
}
public class Timeline extends JPanel {
public Timeline(final ITimelineModel model, IDateSelectorRegistrar registrar) {
registrar.addListener(new DateSelectorListener() {
public void dateChanged(Timestamp from, Timestamp to) {
Timeline.this.removeAll();
Timespan[] timespans = model.getTimespans(from, to);
for(Timespan timespan : timespans) {
TimelineLabel label = new TimelineLabel(timespan);
Timeline.this.add(label);
// label positioning because of Timestamp object data
}
// repaint of timeline
Timeline.this.invalidate();
Timeline.this.repaint();
}
});
}
@Override
protected void paintComponent(Graphics g) {
// paint background grid
super.paintComponent(g);
}
}
