向所有这个gr8 StackOverflow社区致以问候。这是我自己尝试解决之后的第一个问题因此有点长...... :-)
我在使用向下箭头键获取JSpinner的最小指定值时遇到问题。它接受在文本字段中键入的值。其他一切都很好。奇怪的是，这只发生在Spinner模型的某些组合中，特别是new SpinnerNumberModel(29.6, 29.6, 118.1, 0.1)和new SpinnerNumberModel(2.00, 2.00, 6.00, 0.01)。下面是有问题的2 JSpinners的代码。我不确定为什么这些模型会产生问题，如果有更多的模型出现这个问题。
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JSpinner;
import javax.swing.SpinnerNumberModel;
public class JSpinnerBug {
private JFrame frame;
private JSpinner spinner;
private JSpinner spinner_1;
private JButton btnChangeValue_1;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
JSpinnerBug window = new JSpinnerBug();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public JSpinnerBug() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
GridBagLayout gridBagLayout = new GridBagLayout();
gridBagLayout.columnWidths = new int[]{119, 88, 105, 0};
gridBagLayout.rowHeights = new int[]{25, 0, 0};
gridBagLayout.columnWeights = new double[]{0.0, 0.0, 0.0, Double.MIN_VALUE};
gridBagLayout.rowWeights = new double[]{0.0, 0.0, Double.MIN_VALUE};
frame.getContentPane().setLayout(gridBagLayout);
JButton btnChangeValue = new JButton("Change Value");
btnChangeValue.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
spinner.setValue(2.00);
}
});
spinner = new JSpinner();
spinner.setModel(new SpinnerNumberModel(2.01, 2.00, 6.00, 0.01));
GridBagConstraints gbc_spinner = new GridBagConstraints();
gbc_spinner.fill = GridBagConstraints.HORIZONTAL;
gbc_spinner.insets = new Insets(0, 0, 5, 5);
gbc_spinner.gridx = 1;
gbc_spinner.gridy = 0;
frame.getContentPane().add(spinner, gbc_spinner);
GridBagConstraints gbc_btnChangeValue = new GridBagConstraints();
gbc_btnChangeValue.insets = new Insets(0, 0, 5, 0);
gbc_btnChangeValue.anchor = GridBagConstraints.NORTHWEST;
gbc_btnChangeValue.gridx = 2;
gbc_btnChangeValue.gridy = 0;
frame.getContentPane().add(btnChangeValue, gbc_btnChangeValue);
spinner_1 = new JSpinner();
spinner_1.setModel(new SpinnerNumberModel(29.7, 29.6, 118.1, 0.1));
GridBagConstraints gbc_spinner_1 = new GridBagConstraints();
gbc_spinner_1.fill = GridBagConstraints.HORIZONTAL;
gbc_spinner_1.insets = new Insets(0, 0, 0, 5);
gbc_spinner_1.gridx = 1;
gbc_spinner_1.gridy = 1;
frame.getContentPane().add(spinner_1, gbc_spinner_1);
btnChangeValue_1 = new JButton("Change Value");
btnChangeValue_1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
spinner_1.setValue(29.6);
}
});
GridBagConstraints gbc_btnChangeValue_1 = new GridBagConstraints();
gbc_btnChangeValue_1.gridx = 2;
gbc_btnChangeValue_1.gridy = 1;
frame.getContentPane().add(btnChangeValue_1, gbc_btnChangeValue_1);
}
/**
* Custom Spinner to detect button click on
* JSpinner. This class fixes a bug for
* JSpinner like for example for minimum value = 2.00
* and step size 0.01
*
* @author dARKpRINCE
*
*/
class CustomSpinner extends JSpinner{
@Override
public Object getPreviousValue() {
// Circumvent JSpinner bug
NumberEditor spinnerEditor = (NumberEditor) this.getEditor();
SpinnerNumberModel model = spinnerEditor.getModel();
if(model.getMinimum().equals(2.00) && model.getStepSize().equals(0.01)){
if ((Double) getValue() == 2.01) {
return 2.00;
}
else {
return super.getPreviousValue();
}
}
else if(model.getMinimum().equals(29.6) && model.getStepSize().equals(0.1)){
if ((Double) getValue() == 29.7) {
return 29.6;
}
else {
return super.getPreviousValue();
}
}
else {
return super.getPreviousValue();
}
}
}
}
您可以尝试使用new SpinnerNumberModel(55.3, 55.3, 118.1, 0.1)等其他模型。有了它就行了。
我的解决方案是扩展JSpinner（在代码示例的末尾给出）并参与创建此问题的每个模型，这不是最佳的。因此，每个JSpinner都被CustomSpinner取代。
我还检查了JSpinner的源代码，但无法确定/解决问题。任何人都可以告诉我这是一个错误，以及如何最佳地修复它？使用JSpinner的第三方库是我的最后手段。
答案 0 :(得分：2)
BigDecimal#compareTo(...)中的 Double#compareTo(...)：
import java.awt.*;
import java.math.*;
import javax.swing.*;
public class JSpinnerBug2 {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new JSpinnerBug2().makeUI());
frame.setSize(320, 240);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public JComponent makeUI() {
Box box = Box.createVerticalBox();
box.add(new JSpinner(new SpinnerNumberModel(2.01, 2.00, 6.00, 0.01)));
box.add(Box.createVerticalStrut(10));
box.add(new JSpinner(new SpinnerNumberModel(29.7f, 29.6f, 111.8f, 0.1f)));
box.add(Box.createVerticalStrut(10));
box.add(new JSeparator());
//TEST:
double d = 29.7 - 29.6 - 0.1;
System.out.format("(%f-%f-%f>=0): %b%n", 29.7, 29.6, 0.1, d>=0);
System.out.format("(abs(%f-%f-%f)<1.0e-14): %b%n", 29.7, 29.6, 0.1, Math.abs(d)<1.0e-14);
System.out.format("(abs(%f-%f-%f)<1.0e-15): %b%n", 29.7, 29.6, 0.1, Math.abs(d)<1.0e-15);
box.add(new JSpinner(new SpinnerNumberModel(2.01f, 2.00f, 6.00f, 0.01f)));
box.add(Box.createVerticalStrut(10));
box.add(new JSpinner(new SpinnerNumberModel(29.7, 29.6, 111.8, 0.1) {
@Override public Object getPreviousValue() {
Number v = getNumber();
BigDecimal value = new BigDecimal(v.toString());
BigDecimal stepSize = new BigDecimal(getStepSize().toString());
BigDecimal maximum = new BigDecimal(getMaximum().toString());
BigDecimal minimum = new BigDecimal(getMinimum().toString());
BigDecimal newValue;
if (v instanceof Double) {
newValue = value.subtract(stepSize);
} else {
return super.getPreviousValue();
}
if ((maximum != null) && (maximum.compareTo(newValue) < 0)) {
return null;
}
if ((minimum != null) && (minimum.compareTo(newValue) > 0)) {
return null;
} else {
return newValue;
}
}
}));
box.add(Box.createVerticalGlue());
box.setBorder(BorderFactory.createEmptyBorder(20,20,20,20));
return box;
}
}