scrollbardemo.java

Java 程序设计源码 只提供了部分

import java.awt.event.ActionListener;
import java.awt.GridBagLayout;
import java.awt.GridBagConstraints;
import java.awt.BorderLayout;
import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;

import javax.swing.JFrame;
import javax.swing.JScrollBar;
import javax.swing.JPanel;
import javax.swing.JLabel;
import javax.swing.JTextField;
import java.awt.Component;


public class ScrollBarDemo extends JFrame
    implements AdjustmentListener {
  private JScrollBar  vScb = new JScrollBar(JScrollBar.VERTICAL, 0, 0, 0 ,100);
  private JScrollBar hScb = new JScrollBar(JScrollBar.HORIZONTAL, 0, 0, 0, 100);
  private JPanel panel = new JPanel();
  private GridBagLayout layout = new GridBagLayout();
  private GridBagConstraints constraints = new GridBagConstraints();
  private JLabel jlbVScrollBar = new JLabel("垂直滚动条的值",JLabel.CENTER);
  private JLabel jlbHScrollBar = new JLabel("水平滚动条的值",JLabel.CENTER);
  private JTextField jtfVScrollBar = new JTextField();
  private JTextField jtfHScrollBar = new JTextField();

  public ScrollBarDemo() {
    super("ScrollBar");
    setSize(260, 200);
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    this.getContentPane().setLayout(new BorderLayout());
  }

  private void addComponent(JPanel panel, GridBagLayout layout, GridBagConstraints
                        gbc, Component com, int row, int column, int numRows,
                        int numColumns, int Weightx, int Weighty) {
    gbc.gridx = row;
    gbc.gridy = column;
    gbc.gridwidth = numRows;
    gbc.gridheight = numColumns;
    gbc.weightx = Weightx;
    gbc.weighty = Weighty;

    layout.setConstraints(com, gbc);

    panel.add(com);
  }

  public void setLayout() {
    panel.setLayout(layout);
    constraints.anchor = GridBagConstraints.CENTER;
    constraints.fill = GridBagConstraints.HORIZONTAL;

    addComponent(panel, layout, constraints, jlbHScrollBar, 0, 0, 1, 1, 20, 0);
    addComponent(panel, layout, constraints, jtfHScrollBar, 1, 0, 1, 1, 80, 100);
    addComponent(panel, layout, constraints, jlbVScrollBar, 0, 1, 1, 1, 20, 0);
    addComponent(panel, layout, constraints, jtfVScrollBar, 1, 1, 1, 1, 80, 100);

    this.getContentPane().add(panel, BorderLayout.CENTER);
    this.getContentPane().add(vScb, BorderLayout.EAST);
    this.getContentPane().add(hScb, BorderLayout.SOUTH);

    vScb.addAdjustmentListener(this);
    hScb.addAdjustmentListener(this);
  }

  public static void main(String[] args) {
    ScrollBarDemo sbd = new ScrollBarDemo();
    sbd.setLayout();
    sbd.setVisible(true);
  }

  public void adjustmentValueChanged(AdjustmentEvent e) {
    if(e.getSource() == hScb) {
      jtfHScrollBar.setText(String.valueOf(hScb.getValue()));
    }
    else if(e.getSource() == vScb){
      jtfVScrollBar.setText(String.valueOf(vScb.getValue()));
    }
  }
}