我一直在网上搜索我的问题的答案。我找到了一些很好的建议并改变了原来的代码，但我还没有找到我最初问题的答案。
我正在尝试从一系列Jtextfields中获取字符串数据并将它们写入arraylist，然后从arraylist中获取写入的数据并将其传输到相同的文本字段。
public class Form extends javax.swing.JFrame {
public ArrayList<Personal> personalList;
public ArrayList<Business> businessList;
public ArrayList<Personal> displayPersonalList;
public ArrayList<Business> displayBusinessList;
public Form() {
initArrayLists();
}
private void initArrayLists(){
personalList = new ArrayList<Personal>();
businessList = new ArrayList<Business>();
displayPersonalList = new ArrayList<Personal>();
displayBusinessList = new ArrayList<Business>();
}
这是我写入arraylists的提交按钮。
private void submitButtonActionPerformed(java.awt.event.ActionEvent evt)
{
if (contactTypeLabel.getText().equals("Personal Contact")){
Personal p = new Personal();
p.first = firstNameTF.getText();
p.last = lastNameTF.getText();
p.address = addressTF.getText();
p.s = stateTF.getText();
p.zip = zipTF.getText();
p.phone = phoneTF.getText();
p.email = emailTF.getText();
personalList.add(p);
Personal d = new Personal();
d.first = firstNameTF.getText();
displayPersonalList.add(p);
resetTextFields();
}else if (contactTypeLabel.getText().equals("Business Contact")){
Business b = new Business();
b.first = firstNameTF.getText();
b.last = lastNameTF.getText();
b.address = addressTF.getText();
b.s = stateTF.getText();
b.zip = zipTF.getText();
b.phone = phoneTF.getText();
b.email = emailTF.getText();
businessList.add(b);
Business d = new Business();
d.first = firstNameTF.getText();
displayBusinessList.add(d);
resetTextFields();
}
}
这里是更改为显示模式的代码，其中包含一个组合框，应该填充以访问arraylist以使用所选数据填充文本字段
private void displayPersonalButtonActionPerformed(java.awt.event.ActionEvent evt)
{
personalFieldViewer();
submitButton.setVisible(false);
displayComboBox.setVisible(true);
clearTextFields();
for (Object item : displayPersonalList) {
displayComboBox.addItem(item);
}
}
这是组合框操作的代码和填充文本字段的代码
private void displayComboBoxActionPerformed(java.awt.event.ActionEvent evt)
{
int x;
switch (displayComboBox.getSelectedIndex()){
case 0:
for (x = 0; x < x + 8; x ++) {
switch (x){
case 0 :firstNameTF.setText(personalList.get(x).toString());
break;
case 1 :lastNameTF.setText(personalList.get(x).toString());
break;
case 2 :addressTF.setText(personalList.get(x).toString());
break;
case 3 :stateTF.setText(personalList.get(x).toString());
break;
case 4 :zipTF.setText(personalList.get(x).toString());
break;
case 5 :phoneTF.setText(personalList.get(x).toString());
break;
case 6 :dobTF.setText(personalList.get(x).toString());
break;
case 7 :emailTF.setText(personalList.get(x).toString());
break;
}
}
break;
case 1:
for (x = 8; x < x + 8; x ++) {
switch (x){
case 8 :firstNameTF.setText(personalList.get(x).toString());
break;
case 9 :lastNameTF.setText(personalList.get(x).toString());
break;
case 10 :addressTF.setText(personalList.get(x).toString());
break;
case 11 :stateTF.setText(personalList.get(x).toString());
break;
case 12 :zipTF.setText(personalList.get(x).toString());
break;
case 13 :phoneTF.setText(personalList.get(x).toString());
break;
case 14 :dobTF.setText(personalList.get(x).toString());
break;
case 15 :emailTF.setText(personalList.get(x).toString());
break;
}
}
break;
case 2:
for (x = 16; x < x + 8; x ++) {
switch (x){
case 16 :firstNameTF.setText(personalList.get(x).toString());
break;
case 17 :lastNameTF.setText(personalList.get(x).toString());
break;
case 18 :addressTF.setText(personalList.get(x).toString());
break;
case 19 :stateTF.setText(personalList.get(x).toString());
break;
case 20 :zipTF.setText(personalList.get(x).toString());
break;
case 21 :phoneTF.setText(personalList.get(x).toString());
break;
case 22 :dobTF.setText(personalList.get(x).toString());
break;
case 23 :emailTF.setText(personalList.get(x).toString());
break;
}
}
break;
}
}
这里是包含arraylists变量的类。
public class Contacts {
public String first, last, address, s, zip, phone, email;
}
public class Personal extends Contacts{
public String dob;
}
public class Business extends Contacts{
public String title, organization;
}
当我交替尝试使用* .add（textfield.getText（））填充arraylists时; Java不允许使用变量first = firstNameTF.getText（）;然后* .add（第一个）;我得到了同样的错误消息......
请尽量避免否定，我已阅读有关arraylists的API。谢谢。
答案 0 :(得分：0)
您的arraylist声明的类型为Personal或Business。所以这些列表不能添加字符串值。所以当你说personalList.add(textfield.getText());它实际上试图将String对象添加到只能包含Personal对象的列表时。
其次，displayComboBoxActionPerformed()方法中的for循环导致无限循环。 for (x = 0; x < x + 8; x ++)。如果有不同的for循环和switch语句，你可以做类似
private void displayComboBoxActionPerformed(java.awt.event.ActionEvent evt) {
if(displayComboBox.getSelectedIndex() > -1){
int start = displayComboBox.getSelectedIndex() * 8;
for (int x = start; x < start + 8; x ++) {
firstNameTF.setText(personalList.get(x).toString());
}
}
}