conversionpanel.java

java图形用户界面 6.1 HelloWorldSwing 6.2 按钮计数器 6.3 Swing按钮 6.4 温度转换器 6.5 HtmlDemo 6.6 投票器 6.7 TextS

/*
 * 1.1+Swing version.
 */

import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.text.NumberFormat;

public class ConversionPanel extends JPanel {
    DecimalField textField;
    JComboBox unitChooser;
    JSlider slider;
    ConverterRangeModel sliderModel;
    Converter controller;
    Unit[] units;
    String title;
    final static boolean DEBUG = false;
    final static boolean COLORS = false;
    final static int MAX = 10000;

    ConversionPanel(Converter myController, String myTitle, 
                    Unit[] myUnits,
                    ConverterRangeModel myModel) {
        if (COLORS) {
            setBackground(Color.cyan);
        }
        setBorder(BorderFactory.createCompoundBorder(
                        BorderFactory.createTitledBorder(myTitle),
                        BorderFactory.createEmptyBorder(5,5,5,5)));

        //Save arguments in instance variables.
        controller = myController;
        units = myUnits;
        title = myTitle;
        sliderModel = myModel;

        //Add the text field.  It initially displays "0" and needs
        //to be at least 10 columns wide.
        NumberFormat numberFormat = NumberFormat.getNumberInstance();
        numberFormat.setMaximumFractionDigits(2);
        textField = new DecimalField(0, 10, numberFormat); 
        textField.setValue(sliderModel.getDoubleValue());
        textField.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                sliderModel.setDoubleValue(textField.getValue());
            }
        });

        //Add the combo box.
        unitChooser = new JComboBox(); 
        for (int i = 0; i < units.length; i++) { //Populate it.
            unitChooser.addItem(units[i].description);
        }
        unitChooser.setSelectedIndex(0);
        sliderModel.setMultiplier(units[0].multiplier);
        unitChooser.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                //Set new maximums for the sliders.
                int i = unitChooser.getSelectedIndex();
                sliderModel.setMultiplier(units[i].multiplier);
                controller.resetMaxValues(false);
            }
        });

        //Add the slider.
        slider = new JSlider(sliderModel);
        sliderModel.addChangeListener(new ChangeListener() {
            public void stateChanged(ChangeEvent e) {
                textField.setValue(sliderModel.getDoubleValue());
            }
        });

        //Make the textfield/slider group a fixed size.
        JPanel unitGroup = new JPanel() {
            public Dimension getMinimumSize() {
                return getPreferredSize();
            }
            public Dimension getPreferredSize() {
                return new Dimension(150,
                                     super.getPreferredSize().height);
            }
            public Dimension getMaximumSize() {
                return getPreferredSize();
            }
        };
        if (COLORS) {
            unitGroup.setBackground(Color.blue);
        }
        unitGroup.setBorder(BorderFactory.createEmptyBorder(
                                                0,0,0,5));
        unitGroup.setLayout(new BoxLayout(unitGroup, 
                                          BoxLayout.Y_AXIS));
        unitGroup.add(textField);
        unitGroup.add(slider);

        setLayout(new BoxLayout(this, BoxLayout.X_AXIS));
        add(unitGroup);
        add(unitChooser);
        unitGroup.setAlignmentY(TOP_ALIGNMENT);
        unitChooser.setAlignmentY(TOP_ALIGNMENT);
    }

    /** 
     * Returns the multiplier (units/meter) for the currently
     * selected unit of measurement.
     */
    public double getMultiplier() {
        return sliderModel.getMultiplier();
    }

    public double getValue() {
        return sliderModel.getDoubleValue();
    }
}