ScrollBar 调整事件监听器AdjustmentListener

ScrollBar 组件在滑动滚动块时就会触发调整事件，为了监听调整事件，必须给 ScrollBar 组件对象添加一个调 整事件监听器
AdjustmentListener。该监听器只有一个方法，其一般格式如下

public void adjustmentValueChanged(AdjustmentEvent e)
{
      //调整滚动条发生
}

假设现有滚动条组件对象 scrollbar，调整事件使用如下。

scrollbar.addAdjustmentListener(new AdjustmentListener()
{
        public void adjustmentValueChanged(AdjustmentEvent e)
        {
               //调整滚动条 do someting
        }
});

实例如下：

package sup.orange.learn;

import java.awt.*;
import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

/**
 * Created by re-x on 10/27/14.
 */
public class AdjustmentEventDemo extends Frame {

    Scrollbar slider;
    TextField value;
    Label label;

    public AdjustmentEventDemo() {
        super();
        init();
    }

    public void init() {
        setLayout(new GridLayout(1, 3));
        slider = new Scrollbar(Scrollbar.HORIZONTAL, 0, 1, 0, 100);
        slider.addAdjustmentListener(new AdjustmentListener() {
            @Override
            public void adjustmentValueChanged(AdjustmentEvent e) {
                value.setText(Integer.toString(((Scrollbar)e.getSource()).getValue()));
            }
        });
        value = new TextField("0", 5);
        value.setEditable(false);
        label = new Label("0~100");
        label.setBackground(Color.cyan);
        add(label);
        add(slider);
        add(value);
        addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                setVisible(false);
                dispose();
                System.exit(0);
            }
        });

        setSize(300, 50);
        setVisible(true);
    }

    public static void main(String[] args) {
        new AdjustmentEventDemo();
    }
}