java观察者模式同时更新文本字段和条形图
所以我正在做一个观察者模式分配。我有两个窗口，每个窗口有4个字段。在一个窗口中，您可以在4个不同的文本框中键入双值，它们会反映在条形图中4个相应的条形图中
我还可以通过按下鼠标按钮来更改条形图中的条形图，它会移动到指针所在的位置。现在，我也想更新文本字段，但我不知道该怎么做。它似乎收到了一个通知，说明已经发生了变化，但我不知道如何在字段中设置适当的文本。吧台架重新喷漆了。我对文本框也这么做吗
以下是我迄今为止的3个相关类的代码：
酒吧架
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.geom.*;
import javax.swing.*;
import javax.swing.event.*;
import java.util.*;
/**
A class that implements an Observer object that displays a barchart view of
a data model.
*/
public class BarFrame extends JFrame implements ChangeListener, MouseListener
{
private ArrayList<Double> a;
private DataModel dataModel;
private static final int ICON_WIDTH = 200;
private static final int ICON_HEIGHT = 200;
/**
Constructs a BarFrame object
@param dataModel the data that is displayed in the barchart
*/
public BarFrame(DataModel dataModel)
{
this.dataModel = dataModel;
a = dataModel.getData();
setLocation(0,200);
setLayout(new BorderLayout());
addMouseListener(this); // adds the mouse listener in to the bar frame
Icon barIcon = new Icon()
{
public int getIconWidth() { return ICON_WIDTH; }
public int getIconHeight() { return ICON_HEIGHT; }
public void paintIcon(Component c, Graphics g, int x, int y)
{
Graphics2D g2 = (Graphics2D) g;
g2.setColor(Color.red);
double max = (a.get(0)).doubleValue();
for (Double v : a)
{
double val = v.doubleValue();
if (val > max)
max = val;
}
double barHeight = getIconHeight() / a.size();
int i = 0;
for (Double v : a)
{
double value = v.doubleValue();
double barLength = getIconWidth() * value / max;
Rectangle2D.Double rectangle = new Rectangle2D.Double
(0, barHeight * i, barLength, barHeight);
i++;
g2.fill(rectangle);
}
}
};
add(new JLabel(barIcon));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
setVisible(true);
}
/**
Called when the data in the model is changed.
@param e the event representing the change
*/
public void stateChanged(ChangeEvent e)
{
a = dataModel.getData();
// for(Double d: a){
// System.out.println(d);
// }
repaint();
}
@Override
public void mouseClicked(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mousePressed(MouseEvent e) {
// TODO Auto-generated method stub
double max = Collections.max(dataModel.getData());
double value = (double)e.getX() / (double)getWidth()* max;
if( 30 <= e.getY() && e.getY() < 80 ){
//first bar
dataModel.update(0, value);
}
if( 80 <= e.getY() && e.getY() < 130 ){
//second bar
dataModel.update(1, value);
}
if( 130 <= e.getY() && e.getY() < 180 ){
//third bar
dataModel.update(2, value);
}
if( 180 <= e.getY() && e.getY() < 230 ){
//fourth bar
dataModel.update(3, value);
}
}
@Override
public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub
}
}
数据模型
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.ArrayList;
import javax.swing.event.*;
/**
A Subject class for the observer pattern.
*/
public class DataModel
{
ArrayList<Double> data;
ArrayList<ChangeListener> listeners;
/**
Constructs a DataModel object
@param d the data to model
*/
public DataModel(ArrayList<Double> d)
{
data = d;
listeners = new ArrayList<ChangeListener>();
}
/**
Constructs a DataModel object
@return the data in an ArrayList
*/
@SuppressWarnings("unchecked")
public ArrayList<Double> getData()
{
return (ArrayList<Double>) (data.clone());
}
/**
Attach a listener to the Model
@param c the listener
*/
public void attach(ChangeListener c)
{
listeners.add(c);
}
/**
Change the data in the model at a particular location
@param location the index of the field to change
@param value the new value
*/
public void update(int location, double value)
{
data.set(location, new Double(value));
// frame.fieldList[location].setText(Double.toString(value));
for (ChangeListener l : listeners)
{
// System.out.println("l = " + l);
l.stateChanged(new ChangeEvent(this));
}
}
}
文本框
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import java.util.ArrayList;
/**
A class for displaying the model as a column of textfields in a frame.
*/
public class TextFrame extends JFrame implements ChangeListener
{
DataModel dataModel;
JTextField[] fieldList;
private ArrayList<Double> a;
/**
Constructs a JFrame that contains the textfields containing the data
in the model.
@param d the model to display
*/
public TextFrame(DataModel d)
{
dataModel = d;
final Container contentPane = this.getContentPane();
setLayout(new BoxLayout(contentPane, BoxLayout.Y_AXIS));
ArrayList<Double> a = dataModel.getData();
fieldList = new JTextField[a.size()];
// A listener for action events in the text fields
ActionListener l = new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
// Figure out which field generated the event
JTextField c = (JTextField) e.getSource();
int i = 0;
int count = fieldList.length;
while (i < count && fieldList[i] != c)
i++;
String text = c.getText().trim();
try
{
double value = Double.parseDouble(text);
dataModel.update(i, value);
}
catch (Exception exc)
{
c.setText("Error. No update");
}
}
};
final int FIELD_WIDTH = 11;
for (int i = 0; i < a.size(); i++)
{
JTextField textField = new JTextField(a.get(i).toString(),FIELD_WIDTH);
textField.addActionListener(l);
add(textField);
fieldList[i] = textField;
}
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
setVisible(true);
}
/**
Called when the data in the model is changed.
@param e the event representing the change
*/
public void stateChanged(ChangeEvent e)
{
a = dataModel.getData();
// for(Double d: a){
// System.out.println(d);
// }
}
}
以下是几条注释： 我知道，如果你用maxed值来改变条的值（其他条会移动），那就有问题了。这是我应该扩展的代码。我猜是这样的，这样就可以用作参考点。 我知道我可以通过使用适配器摆脱不必要的鼠标侦听器，但我的指令将它们声明为空
如果有人想回答这个问题，还有一个额外的问题：有没有办法在我的鼠标按下时获得实际的双精度？它总是返回一个整数
总之，很抱歉发了这么长的帖子。提前感谢您的帮助
# 1 楼答案
想出来了！ 我在TextFrame中的stateChanged方法中添加了以下内容：