先列出代码
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class JTextFieldGui{
JTextField textField;
JLabel labelInput;
JLabel labelOutput;
public static void main(String[] args) {
JTextFieldGui gui = new JTextFieldGui();
gui.go();
}
public void go(){
JFrame frame = new JFrame();
JPanel panelInput = new JPanel();
JPanel panelOutput = new JPanel();
labelInput = new JLabel("Your first name: ");
labelOutput = new JLabel("Enter your name, and you will see it here.");
textField = new JTextField(20);//<---问题1
JButton enter = new JButton("Enter");
JButton selectAll = new JButton("Select all text");
frame.setSize(300,200);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panelInput.setLayout(new BoxLayout(panelInput, BoxLayout.X_AXIS));
textField.addActionListener(new LabelActionListener());
enter.addActionListener(new LabelActionListener());
selectAll.addActionListener(new TextFieldActionlistener());
frame.getContentPane().add(BorderLayout.NORTH, panelInput);
panelInput.add(labelInput);
panelInput.add(textField);
panelInput.add(enter);
panelInput.add(selectAll);
frame.getContentPane().add(BorderLayout.CENTER, panelOutput);
panelOutput.add(labelOutput);
}
class LabelActionListener implements ActionListener{
public void actionPerformed(ActionEvent event){
labelOutput.setText(textField.getText());
}
}
class TextFieldActionlistener implements ActionListener{
public void actionPerformed(ActionEvent event){
textField.selectAll();//<---问题2
}
}
}
问题1:已经定义了textfield的大小为20列,但是,结果还是会占满整行
问题2:创建并监听了一个按钮selectall,用于全选textfield中的字符,但是并没有反应,是什么原因呢
问题3:另外之前还有个莫名其妙的错误,现在又没有了,无法将类 JTextField中的构造器 JTextField应用到给定类型,下面还有几行,写的是,需要:没有参数,总之就是说JTextField(int)是错误的
求指教!!!