[英]JFrame: How to add a button that adds a new text field to the frame?
我對 Java 還是很陌生,我想我會嘗試弄臟我的手並制作一個 GUI,但我似乎無法讓它按照我想要的方式工作。
我寫了一些代碼,認為如果我按下 GUI 上的“添加”按鈕,那么新的 JTextField 將出現在所有其他文本字段的下方,但這不會發生。 只有一個新的 JTextField 確實出現,但它出現在我的添加按鈕旁邊,而不是在我擁有的所有其他文本字段下方,如果我再次按下它,則沒有任何反應。 我嘗試使用其他變量,但它似乎無法正常工作。 我覺得我的 ActionListener 有問題,但我不知道是什么。
public class TheGUI extends JFrame{
List<JTextField> listOfTextFields = new ArrayList<JTextField>();
private JTextField desc1;
private JTextField instruct;
private JTextField desc2;
private JButton submit;
private JButton addNew;
public TheGUI() { //My GUI with the default fields & buttons that should be on there.
super("Chili");
setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
instruct = new JTextField("Choose your words");
instruct.setEditable(false);
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridx = 0;
c.gridy = 0;
add(instruct, c);
addNew = new JButton("Add");
c.weightx = 0.0;
c.gridx = 1;
c.gridy = 0;
add(addNew, c);
submit = new JButton("Submit!");
c.weightx = 0.5;
c.gridwidth = 2;
c.gridx = 0;
c.gridy = GridBagConstraints.PAGE_END;
add(submit, c);
desc1 = new JTextField(10);
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridwidth = 2;
c.gridx = 0;
c.gridy = 1;
add(desc1, c);
desc2 = new JTextField(10);
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridwidth = 2;
c.gridx = 0;
c.gridy = 2;
add(desc2, c);
addNew.addActionListener(new Adder());
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(300,300);
setVisible(true);
}
private class Adder implements ActionListener {
@Override
public void actionPerformed(ActionEvent event) {
int i = 0;
listOfTextFields.add(new JTextField());
GridBagConstraints textFieldConstraints = new GridBagConstraints();
//Give it a max of 9 text fields that can be created.
while(i < 10) {
textFieldConstraints.fill = GridBagConstraints.HORIZONTAL;
textFieldConstraints.weightx = 0.5;
textFieldConstraints.gridx = 0;
textFieldConstraints.gridwidth = 2;
textFieldConstraints.gridy = 3 + i;
i++;
}
add(listOfTextFields.get(i), textFieldConstraints);
revalidate();
repaint();
}
}
}
你的 while 循環真的很奇怪。
您的ActionListener
應如下所示:
private class Adder implements ActionListener {
@Override
public void actionPerformed(ActionEvent event) {
if (listOfTextFields.size() == 9) {
// Give it a max of 9 text fields that can be created.
return;
}
JTextField textfield = new JTextField();
listOfTextFields.add(textfield);
GridBagConstraints textFieldConstraints = new GridBagConstraints();
textFieldConstraints.fill = GridBagConstraints.HORIZONTAL;
textFieldConstraints.weightx = 0.5;
textFieldConstraints.gridx = 0;
textFieldConstraints.gridwidth = 2;
textFieldConstraints.gridy = 3 + listOfTextFields.size();
add(textfield, textFieldConstraints);
revalidate();
repaint();
}
}
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