java 如何在滑块移动时调用动作侦听器，而不仅仅是在松开鼠标时？
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How do I call an actionlistener while the slider is moving, not just when I let go of the mouse?
提问by user525479
class AngleSlider implements ChangeListener {
public void stateChanged(ChangeEvent e) {
JSlider source = (JSlider) e.getSource();
if (!source.getValueIsAdjusting()) {
double dAngle = (double)source.getValue();
pnlCannon.dCannonAngle=Math.toRadians(dAngle);
pnlCannon.repaint();
}
}
}
This is our current event listener. Is there a different listener required to do what I want?
这是我们当前的事件监听器。是否需要不同的听众来做我想做的事？
回答by dacwe
No, you will only need to removethe getValueIsAdjusting()check. So, this will repaint your cannon when you move your mouse:
不，你只需要删除的getValueIsAdjusting()检查。因此，当您移动鼠标时，这将重新绘制您的大炮：
class AngleSlider implements ChangeListener {
public void stateChanged(ChangeEvent e) {
JSlider source = (JSlider) e.getSource();
double dAngle = (double)source.getValue();
pnlCannon.dCannonAngle=Math.toRadians(dAngle);
pnlCannon.repaint();
}
}
This is another example that shows the same, it will print the value of the slider as you move it:
这是另一个显示相同内容的示例，它会在您移动滑块时打印滑块的值：
public static void main(String[] args) {
JFrame frame = new JFrame("Test");
JSlider slider = new JSlider();
slider.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent ce) {
System.out.println(((JSlider) ce.getSource()).getValue());
}
});
frame.add(slider);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 300);
frame.setVisible(true);
}
回答by MikelRascher
The !source.getValueIsAdjusting()is preventing the update code form executing.
的!source.getValueIsAdjusting()是防止在更新代码的形式执行。
Why do you think that condition is necessary?
为什么你认为这个条件是必要的？
