Java Swing 标签重叠

Question

public class Solution{

    public static void main(String[] args){

        MyGraphic frame = new MyGraphic();
        frame.setComponents();
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300, 300);
    }
}
class MyGraphic extends JFrame implements ActionListener{

    JButton b;
    JTextField t;
    JLabel l;
    public MyGraphic(String s){

        super(s);
    }
    public MyGraphic(){

        super();
    }
    public void setComponents(){

        b = new JButton("Action");
        t = new JTextField();
        l = new JLabel("Name");
        this.setLayout(null);
        l.setBounds(30, 50, 50, 20);
        t.setBounds(100, 50, 150, 20);
        b.setBounds(100, 100, 70, 20);
        this.add(b);
        this.add(t);
        this.add(l);
        b.addActionListener(this);
    }
    public void actionPerformed(ActionEvent e){

        String name = t.getText();
        JLabel label = new JLabel("Your name is "+name);
        label.setBounds(50, 150, 200, 30);
        this.add(label);
    }
}

image link
In this image link name are overlapping. First, I entered "Sagar Tanwar" then I entered "Sumit Kumar" and these name are overlapping. Please tell me, How to remove previous entered Label. You can check image using this image link.

Answer 1

You should heed the advice in the comments to your question. Nonetheless, the simplest way to fix your problem, using the code you have already written, is to make label a member of class MyGraphic rather than a local variable in method actionPerformed() , ie

class MyGraphic extends JFrame implements ActionListener{
    JLabel label;
    // Rest of the class code

Then, in method actionPerformed() simply set the text of the label .

public void actionPerformed(ActionEvent e) {
    if (label == null) {
        label = new JLabel();
        label.setBounds(50, 150, 200, 30);
        this.add(label);
    }
    String name = t.getText();
    label.setText("Your name is "+name);
}