Google Tag Manager

2019/02/27

aterai

Limit the movable range of JSlider's value

Code

public static final int MAXI = 80;
public static final int MINI = 40;

private static class MetalDragLimitedSliderUI extends MetalSliderUI {
  @Override protected TrackListener createTrackListener(JSlider slider) {
    return new TrackListener() {
      @Override public void mouseDragged(MouseEvent e) {
        // case HORIZONTAL:
        int halfThumbWidth = thumbRect.width / 2;
        int thumbLeft = e.getX() - offset;
        int maxPos = xPositionForValue(MAXI) - halfThumbWidth;
        int minPos = xPositionForValue(MINI) - halfThumbWidth;
        if (thumbLeft > maxPos) {
          e.translatePoint(maxPos + offset - e.getX(), 0);
        } else if (thumbLeft < minPos) {
          e.translatePoint(minPos + offset - e.getX(), 0);
        }
        super.mouseDragged(e);
      }
    };
  }
}

private static JSlider makeSilder(String title) {
  JSlider slider = new JSlider(0, 100, 40);
  slider.setBorder(BorderFactory.createTitledBorder(title));
  slider.setMajorTickSpacing(10);
  slider.setPaintTicks(true);
  slider.setPaintLabels(true);
  Dictionary<?, ?> dictionary = slider.getLabelTable();
  if (Objects.nonNull(dictionary)) {
    Enumeration<?> elements = dictionary.elements();
    while (elements.hasMoreElements()) {
      JLabel label = (JLabel) elements.nextElement();
      int v = Integer.parseInt(label.getText());
      if (v > MAXI || v < MINI) {
        label.setForeground(Color.RED);
      }
    }
  }
  slider.getModel().addChangeListener(e -> {
    BoundedRangeModel m = (BoundedRangeModel) e.getSource();
    if (m.getValue() > MAXI) {
      m.setValue(MAXI);
    } else if (m.getValue() < MINI) {
      m.setValue(MINI);
    }
  });
  return slider;
}

References