Broken GUI after adding JTextField

Question

i have a strange(?) problem . I'm making a simple GUI and when i add a JTextField (commented ) some components dissappear . I don't know why . Furthermore , sometimes when i play my GUI some components dissappear randomly ( first play, some buttons dissappear , second play - some labels dissappear ) it's so strange ! Any ideas why ?

    import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;


public class matchWindow extends JFrame implements ActionListener{


    private static final long serialVersionUID = 1L;

    private JTextField tAttack;

    public matchWindow(){

        setTitle("Match");
        setSize(960, 720);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
        setLayout(null);

        JLabel lPlayers = new JLabel("Players list");
        lPlayers.setBounds(50, 10, 100, 30);
        lPlayers.setVisible(true);
        add(lPlayers);

        JLabel lAction = new JLabel("Action list");
        lAction.setBounds(250, 10, 100, 30);
        lAction.setVisible(true);
        add(lAction);

        JLabel lStats = new JLabel("Player statistics");
        lStats.setBounds(650, 10, 100, 30);
        lStats.setVisible(true);
        add(lStats);

        JLabel lAttack = new JLabel("Attack");
        lAttack.setBounds(175, 45, 50, 30);
        lAttack.setVisible(true);
        add(lAttack);


        JLabel lAttackPrec = new JLabel("Attack");
        lAttackPrec.setBounds(550, 45, 50, 30);
        lAttackPrec.setVisible(true);
        add(lAttackPrec);

        //tAttack = new JTextField();
        //tAttack.setBounds(550, 75, 50, 30);
        //tAttack.setVisible(true);
        //add(tAttack);



        JLabel lDefense = new JLabel("Defense");
        lDefense.setBounds(230, 45, 60, 30);
        lDefense.setVisible(true);
        add(lDefense);

        JLabel lDefensePrec = new JLabel("Defense");
        lDefensePrec.setBounds(620, 45, 60, 30);
        lDefensePrec.setVisible(true);
        add(lDefensePrec);

        JLabel lServe = new JLabel("Serve");
        lServe.setBounds(300, 45, 50, 30);
        lServe.setVisible(true);
        add(lServe);

        JLabel lServePrec = new JLabel("Serve");
        lServePrec.setBounds(690, 45, 50, 30);
        lServePrec.setVisible(true);
        add(lServePrec);

        JLabel lBlock = new JLabel("Block");
        lBlock.setBounds(355, 45, 50, 30);
        lBlock.setVisible(true);
        add(lBlock);


        JButton bY1 = new JButton("Y");
        bY1.setBounds(160, 75, 25, 25);
        bY1.setVisible(true);
        add(bY1);
        JButton bN1 = new JButton("N");
        bN1.setBounds(190, 75, 25, 25);
        bN1.setVisible(true);
        add(bN1);

        JButton bY2 = new JButton("Y");
        bY2.setBounds(225, 75, 25, 25);
        bY2.setVisible(true);
        add(bY2);
        JButton bN2 = new JButton("N");
        bN2.setBounds(255, 75, 25, 25);
        bN2.setVisible(true);
        add(bN2);

        JButton bY3 = new JButton("Y");
        bY3.setBounds(290, 75, 25, 25);
        bY3.setVisible(true);
        add(bY3);
        JButton bN3 = new JButton("N");
        bN3.setBounds(320, 75, 25, 25);
        bN3.setVisible(true);
        add(bN3);

        JButton bY4 = new JButton("Y");
        bY4.setBounds(350, 75, 25, 25);
        bY4.setVisible(true);
        add(bY4);
        JButton bN4 = new JButton("N");
        bN4.setBounds(380, 75, 25, 25);
        bN4.setVisible(true);
        add(bN4);





    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        matchWindow window = new matchWindow();
        window.setVisible(true);

    }

    @Override
    public void actionPerformed(ActionEvent e) {
        // TODO Auto-generated method stub

    }

}

Answer 1

    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;

    import javax.swing.JButton;
    import javax.swing.JFrame;
    import javax.swing.JLabel;
    import javax.swing.JTextField;


     public class matchWindow extends JFrame implements ActionListener{


     private static final long serialVersionUID = 1L;

     private JTextField tAttack;

    public matchWindow(){

    setTitle("Match");
    setSize(960, 720);
    setLocationRelativeTo(null);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setVisible(true);
    setLayout(null);

    JLabel lPlayers = new JLabel("Players list");
    lPlayers.setBounds(50, 10, 100, 30);
    lPlayers.setVisible(true);
    add(lPlayers);

    JLabel lAction = new JLabel("Action list");
    lAction.setBounds(250, 10, 100, 30);
    lAction.setVisible(true);
    add(lAction);

    JLabel lStats = new JLabel("Player statistics");
    lStats.setBounds(650, 10, 100, 30);
    lStats.setVisible(true);
    add(lStats);

    JLabel lAttack = new JLabel("Attack");
    lAttack.setBounds(175, 45, 50, 30);
    lAttack.setVisible(true);
    add(lAttack);


    JLabel lAttackPrec = new JLabel("Attack");
    lAttackPrec.setBounds(550, 45, 50, 30);
    lAttackPrec.setVisible(true);
    add(lAttackPrec);

    tAttack = new JTextField();
    tAttack.setBounds(500, 75, 50, 30);
    tAttack.setVisible(true);
    add(tAttack);



    JLabel lDefense = new JLabel("Defense");
    lDefense.setBounds(230, 45, 60, 30);
    lDefense.setVisible(true);
    add(lDefense);

    JLabel lDefensePrec = new JLabel("Defense");
    lDefensePrec.setBounds(620, 45, 60, 30);
    lDefensePrec.setVisible(true);
    add(lDefensePrec);

    JLabel lServe = new JLabel("Serve");
    lServe.setBounds(300, 45, 50, 30);
    lServe.setVisible(true);
    add(lServe);

    JLabel lServePrec = new JLabel("Serve");
    lServePrec.setBounds(690, 45, 50, 30);
    lServePrec.setVisible(true);
    add(lServePrec);

    JLabel lBlock = new JLabel("Block");
    lBlock.setBounds(355, 45, 50, 30);
    lBlock.setVisible(true);
    add(lBlock);


    JButton bY1 = new JButton("Y");
    bY1.setBounds(160, 75, 25, 25);
    bY1.setVisible(true);
    add(bY1);
    JButton bN1 = new JButton("N");
    bN1.setBounds(190, 75, 25, 25);
    bN1.setVisible(true);
    add(bN1);

    JButton bY2 = new JButton("Y");
    bY2.setBounds(225, 75, 25, 25);
    bY2.setVisible(true);
    add(bY2);
    JButton bN2 = new JButton("N");
    bN2.setBounds(255, 75, 25, 25);
    bN2.setVisible(true);
    add(bN2);

    JButton bY3 = new JButton("Y");
    bY3.setBounds(290, 75, 25, 25);
    bY3.setVisible(true);
    add(bY3);
    JButton bN3 = new JButton("N");
    bN3.setBounds(320, 75, 25, 25);
    bN3.setVisible(true);
    add(bN3);

    JButton bY4 = new JButton("Y");
    bY4.setBounds(350, 75, 25, 25);
    bY4.setVisible(true);
    add(bY4);
    JButton bN4 = new JButton("N");
    bN4.setBounds(380, 75, 25, 25);
    bN4.setVisible(true);
    add(bN4);





}

public static void main(String[] args) {
    // TODO Auto-generated method stub
    matchWindow window = new matchWindow();
    window.setVisible(true);

}

@Override
public void actionPerformed(ActionEvent e) {
    // TODO Auto-generated method stub

}

}

You are over writing Component That way that is overwriting i am fixed problem of your code

Answer 2

First add your components than make the frame visible. In the constructor you have a setVisible(true) delete it. OFFTOPIC: And use Layoutmanagers not "Null-Layout".