源代码附于下方。两个JTextField以相同的方式构造。但我不知道为什么第二个的setText（String）方法不起作用。
package ztio.gui.updateGUI;
import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.TitledBorder;
public class SimpleSettingDialog extends JDialog {
private final int MAX_THRES_NUM = 10;
private final int MAX_VALUE_THRES_NUM = 10;
private JPanel dialogPane;
private JComboBox testCaseCombo;
private JComboBox testCaseItemCombo;
private JComboBox[] judgeOperationComboArray = new JComboBox[MAX_THRES_NUM];
private JComboBox[] thresTypeComboArray = new JComboBox[MAX_THRES_NUM];
private String[] judgeOperationStrings;
private String[] thresTypeStrings;
private List<JButton> testBtnList;
private JTextField showTargetChoice;
private JTextField showTestCase;
public SimpleSettingDialog(JFrame parent, boolean isModal) {
// TODO Auto-generated constructor stub
super(parent, isModal);
String[] judges = {">", "<", "="};
String[] types = {"int", "float", "string"};
judgeOperationStrings = judges;
thresTypeStrings = types;
dialogPane = (JPanel) getContentPane();
dialogPane.setLayout(new GridBagLayout());
TitledBorder titled = BorderFactory.createTitledBorder("Config Thresholds");
dialogPane.setBorder(titled);
JPanel testCasePanel = createTestCasePanel();
GridBagConstraints c = new GridBagConstraints();
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 1.0;
c.weighty = 0.0;
c.gridwidth = 1;
c.gridx = 0;
c.gridy = 0;
dialogPane.add(testCasePanel, c);
c.fill = GridBagConstraints.BOTH;
c.ipady = 0;
c.weightx = 1.0;
c.weighty = 1.0;
c.gridwidth = 1;
c.gridx = 0;
c.gridy = 1;
JPanel testItemPanel = createTestCaseItemPanel();
JPanel debug = new JPanel();
dialogPane.add(debug, c);
}
private JPanel createThresListPanel() {
JPanel thresListPanel = new JPanel();
thresListPanel.setLayout(new BoxLayout(thresListPanel, BoxLayout.Y_AXIS));
for(int i = 0; i < 2; ++i){
JPanel thresPanel = createThresPanel(i);
thresListPanel.add(thresPanel);
}
return thresListPanel;
}
private JPanel createThresPanel(int i) {
// TODO Auto-generated method stub
JPanel thresPanel = new JPanel(new GridBagLayout());
TitledBorder titled = BorderFactory.createTitledBorder("The " + (((i+1)==1)?"1st":((i+1)==2?"2nd":((i+1==3?"3rd":((i+1)+"th"))))) + " Threshold" );
thresPanel.setBorder(titled);
JComboBox thresTypeCombo = new JComboBox(thresTypeStrings);
thresTypeComboArray[i] = thresTypeCombo;
thresTypeCombo.setSelectedItem("string");
JComboBox judgeOperationCombo = new JComboBox(judgeOperationStrings);
judgeOperationComboArray[i] = judgeOperationCombo;
judgeOperationCombo.setSelectedItem("=");
JLabel label1 = new JLabel("Threshold's type:");
JLabel label2 = new JLabel("Judge Operation:");
GridBagConstraints c = new GridBagConstraints();
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 0.0;
c.gridwidth = 1;
c.gridx = 0;
c.gridy = 0;
thresPanel.add(label1, c);
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 1.0;
c.gridwidth = 1;
c.gridx = 1;
c.gridy = 0;
thresPanel.add(thresTypeCombo, c);
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 0.0;
c.gridwidth = 1;
c.gridx = 0;
c.gridy = 1;
thresPanel.add(label2, c);
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 1.0;
c.gridwidth = 1;
c.gridx = 1;
c.gridy = 1;
thresPanel.add(judgeOperationCombo, c);
return thresPanel;
}
private JPanel createTestCaseItemPanel() {
// TODO Auto-generated method stub
String[] testItemNameArray = {"volume", "brightness"};
testCaseItemCombo = new JComboBox(testItemNameArray);
testCaseItemCombo.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
JComboBox cb = (JComboBox)e.getSource();
String caseItemName = (String)cb.getSelectedItem();
String caseName = (String)testCaseCombo.getSelectedItem();
String targetString = caseName + "->" + caseItemName;
System.out.println(targetString);
System.out.println("target text field: " + showTargetChoice.getText());
showTargetChoice.setText(targetString);
}
});
TitledBorder titled;
titled = BorderFactory.createTitledBorder("Test Case Item");
JPanel comp = new JPanel(new GridBagLayout());
comp.setBorder(titled);
JButton btnAddTestCaseItem = new JButton("ADD");
btnAddTestCaseItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
}
});
JButton btnDelTestCaseItem = new JButton("DEL");
btnDelTestCaseItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
}
});
GridBagConstraints c = new GridBagConstraints();
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 0.0;
c.gridwidth = 1;
c.gridx = 0;
c.gridy = 0;
comp.add(testCaseItemCombo, c);
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 0.0;
c.gridwidth = 1;
c.gridx = 1;
c.gridy = 0;
comp.add(btnAddTestCaseItem, c);
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 0.0;
c.gridwidth = 1;
c.gridx = 2;
c.gridy = 0;
comp.add(btnDelTestCaseItem, c);
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 1.0;
c.gridwidth = 1;
c.gridx = 3;
c.gridy = 0;
comp.add(new JPanel(), c);
//Row 2
JLabel labelRegexp = new JLabel("target string:");
showTargetChoice = new JTextField();
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 0.0;
c.gridwidth = 1;
c.gridx = 0;
c.gridy = 1;
comp.add(labelRegexp, c);
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 0.0;
c.gridwidth = 3;
c.gridx = 1;
c.gridy = 1;
comp.add(showTargetChoice, c);
JPanel thresListPanel = createThresListPanel();
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 0.0;
c.gridwidth = 4;
c.gridx = 0;
c.gridy = 2;
comp.add(thresListPanel, c);
return comp;
}
private JPanel createTestCasePanel() {
// TODO Auto-generated method stub
String[] testCaseArray = {"Light", "Voice"};
testCaseCombo = new JComboBox(testCaseArray);
testCaseCombo.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
JComboBox cb = (JComboBox)e.getSource();
String caseName = (String)cb.getSelectedItem();
System.out.println(caseName);
showTestCase.setText(caseName);
}
});
TitledBorder titled;
titled = BorderFactory.createTitledBorder("Test Case");
JPanel comp = new JPanel(new GridBagLayout());
comp.setBorder(titled);
JButton btnAddTestCase = new JButton("ADD");
btnAddTestCase.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
}
});
JButton btnDelTestCase = new JButton("DEL");
btnDelTestCase.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
}
});
GridBagConstraints c = new GridBagConstraints();
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 0.0;
c.gridwidth = 1;
c.gridx = 0;
c.gridy = 0;
comp.add(testCaseCombo, c);
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 0.0;
c.gridwidth = 1;
c.gridx = 1;
c.gridy = 0;
comp.add(btnAddTestCase, c);
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 0.0;
c.gridwidth = 1;
c.gridx = 2;
c.gridy = 0;
comp.add(btnDelTestCase, c);
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 1.0;
c.gridwidth = 1;
c.gridx = 3;
c.gridy = 0;
comp.add(new JPanel(), c);
JLabel label = new JLabel("selected test case:");
showTestCase = new JTextField();
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 0.0;
c.gridwidth = 1;
c.gridx = 0;
c.gridy = 1;
comp.add(label, c);
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 1.0;
c.gridwidth = 3;
c.gridx = 1;
c.gridy = 1;
comp.add(showTestCase, c);
JPanel testCaseItemPanel = createTestCaseItemPanel();
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;
c.weightx = 0.0;
c.gridwidth = 4;
c.gridx = 0;
c.gridy = 2;
comp.add(testCaseItemPanel, c);
return comp;
}
private static void createAndShowGUI() {
JFrame frame = new JFrame("SimpleSettingDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton btn = new JButton("open setting dialog");
btn.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
SimpleSettingDialog simpleSettingDialog = new SimpleSettingDialog(frame, true);
simpleSettingDialog.pack();
simpleSettingDialog.setVisible(true);
}
});
frame.getContentPane().add(btn);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (UnsupportedLookAndFeelException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
答案 0 :(得分：2)
createTestCaseItemPanel()执行两次。从createTestCasePanel()执行后。第二次在构造函数的这一行：
JPanel testItemPanel = createTestCaseItemPanel();
第二次调用会创建一个未使用的局部变量testItemPanel。但是这会覆盖一些成员，其中一个是showTargetChoice，现在指向一个不可见的字段。
解决问题只是摆脱第二次通话。