我正在制作一个java welcome GUI。用户输入他的名字，姓氏，年龄，性别，它将显示给他。如果用户没有输入除名字和姓氏之外的字段，我会设置警告。它会针对年龄，状态和性别发出警告，但会跳过名称的警告并转到try / catch。我不明白为什么会这样做，如何修复它以显示警告？
buttonWelcome.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent pressing) {
int userAge;
// a try/catch to catch any error and display
// back to the user that he must finish
try {
String first = firstname.getText();
String last = lastname.getText();
Object state = stateBox.getSelectedItem();
userAge = Integer.parseInt(age.getText());
boolean male = maleButton.isSelected();
boolean female = femaleButton.isSelected();
// warning section
if (firstname.getText().trim().equals("")) {
JOptionPane.showMessageDialog(null,
"Must enter first name");
} else if (lastname.getText().trim().equals("")) {
JOptionPane.showMessageDialog(null,
"Must enter last name");
} else if (userAge <= 0) {
JOptionPane.showMessageDialog(null,
"Must be a positive age");
} else if (stateBox.getSelectedIndex() == 0) {
JOptionPane
.showMessageDialog(null, "Must select state");
} else if (buttonGenders.isSelected(null)) {
JOptionPane.showMessageDialog(null,
"Must select gender");
}
if (male) {
textArea.setText("Welcome Male " + first + ", " + last
+ " of " + userAge + " years old from " + state);
} else if (female) {
textArea.setText("Welcome Female " + first + ", "
+ last + " of " + userAge + " years old from "
+ state);
}
// display back the error as a pop up
} catch (Exception e) {
JOptionPane.showMessageDialog(null,
"Must Complete your Info");
}
}
});