从 JSlider 的值更改 JLabel 的值

发布于 2024-08-01 23:55:04 字数 595 浏览 6 评论 0原文

我有一个包含 JSlider 和 JLabel 的 JPanel。我想对其进行配置，以便当用户更改 JSlider 的值时，JLabel 会反映该新值。

我知道我可以使用 Slider 触发 ChangeEvents，但我不知道如何向 JLabel 添加 ChangeListener。这是我的代码片段。

scaleSlider.addChangeListener(new ChangeListener() {
    public void stateChanged(ChangeEvent event)
    {
        int currentTime = ((JSlider)event.getSource()).getValue();
        doSomething(currentTime);
        fireStateChanged(event);
    }

JLabel timeValue = new JLabel("Time: " + scaleSlider.getValue());
timeValue.add???

（我不知道现在要做什么来反映滑块中的变化）

我的方向正确吗？在此先感谢您的帮助。

原文

I have a single JPanel that contains a JSlider and a JLabel. I want to configure it so that when the JSlider's value is being changed by the user, that new value is reflected by the JLabel.

I understand that I can fire ChangeEvents with the Slider, but I don't know how to add a ChangeListener to the JLabel. Here's a snippet of my code.

scaleSlider.addChangeListener(new ChangeListener() {
    public void stateChanged(ChangeEvent event)
    {
        int currentTime = ((JSlider)event.getSource()).getValue();
        doSomething(currentTime);
        fireStateChanged(event);
    }

JLabel timeValue = new JLabel("Time: " + scaleSlider.getValue());
timeValue.add???

(I don't know what to do here now to reflect the changes in the slider)

Am I going in the right direction with this? Thanks in advance for your help.

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三生一梦 2024-08-08 23:55:04

您不会监听 JLabel 上的 ChangeEvents。您在 JSlider 上侦听 ChangeEvents，然后在 stateChanged() 方法中，您只需使用

label.setText("Time: " + scaleSlider.getValue());

也不需要从 ChangeLisetner 触发任何事件。

You don't listen for ChangeEvents on a JLabel. You listen for ChangeEvents on the JSlider and then in the stateChanged() method you simply use

label.setText("Time: " + scaleSlider.getValue());

No need to fire any event from the ChangeLisetner either.

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染火枫林 2024-08-08 23:55:04

您不需要向 JLabel 添加更改侦听器。如果您的 JLabel 是包含代码的类的成员字段，您可以在 JSlider 的更改侦听器中引用 JLabel，如下所示：

public class Test() {
    private JLabel label;

    private void setup() {
        label = new JLabel();
        JSlider scaleSlider = new JSlider();
        scaleSlider.addChangeListener(new ChangeListener() {

            public void stateChanged(ChangeEvent event) {
                int currentTime = ((JSlider)event.getSource()).getValue();
                label.setText(currentTime);
            }
        }
    }
}

您可以在任何内部类（甚至是匿名内部类）中引用任何外部类的字段您在scaleSlider上声明的ChangeListener。

You don't need to add a change listener to the JLabel. If your JLabel is a member field of the class that contains the code, you can refer to the JLabel within the JSlider's change listener, like so:

public class Test() {
    private JLabel label;

    private void setup() {
        label = new JLabel();
        JSlider scaleSlider = new JSlider();
        scaleSlider.addChangeListener(new ChangeListener() {

            public void stateChanged(ChangeEvent event) {
                int currentTime = ((JSlider)event.getSource()).getValue();
                label.setText(currentTime);
            }
        }
    }
}

You can refer to any outer class's field within any inner-class, even the anonymous inner-class ChangeListener you've declared on the scaleSlider.

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