Java 正在运行的应用程序上的 Swing JLabel 文本更改
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Swing JLabel text change on the running application
提问by JavaBits
I have a Swing window which contains a button a text box and a JLabelnamed as flag. According to the input after I click the button, the label should change from flag to some value.
我有一个 Swing 窗口，其中包含一个按钮、一个文本框和一个JLabel命名为标志。根据单击按钮后的输入，标签应从标志更改为某个值。
How to achieve this in the same window?
如何在同一窗口中实现这一点？
采纳答案by Eng.Fouad
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import java.awt.event.*;
public class Test extends JFrame implements ActionListener
{
private JLabel label;
private JTextField field;
public Test()
{
super("The title");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setPreferredSize(new Dimension(400, 90));
((JPanel) getContentPane()).setBorder(new EmptyBorder(13, 13, 13, 13) );
setLayout(new FlowLayout());
JButton btn = new JButton("Change");
btn.setActionCommand("myButton");
btn.addActionListener(this);
label = new JLabel("flag");
field = new JTextField(5);
add(field);
add(btn);
add(label);
pack();
setLocationRelativeTo(null);
setVisible(true);
setResizable(false);
}
public void actionPerformed(ActionEvent e)
{
if(e.getActionCommand().equals("myButton"))
{
label.setText(field.getText());
}
}
public static void main(String[] args)
{
new Test();
}
}
回答by Harry Joy
Use setText(str)method of JLabelto dynamically change text displayed. In actionPerform of button write this:
使用setText(str)方法JLabel来动态改变显示的文本。在 actionPerform 按钮写这个：
jLabel.setText("new Value");
A simple demo code will be:
一个简单的演示代码将是：
JFrame frame = new JFrame("Demo");
frame.setLayout(new BorderLayout());
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.setSize(250,100);
final JLabel label = new JLabel("flag");
JButton button = new JButton("Change flag");
button.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent arg0) {
label.setText("new value");
}
});
frame.add(label, BorderLayout.NORTH);
frame.add(button, BorderLayout.CENTER);
frame.setVisible(true);
