Java JTextfield gives me only null data
I made a Mainmenu JFrame which can generate 4 different new frame represents each menu. Mainmenu frame was works fine. but I found that it could't get text from new frame textfield. here is error report and source code. please let me know how to fix it.
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.WindowConstants;
import javax.swing.JTable;
public class PhoneBook extends JFrame implements ActionListener
{
private String[] colName;
JPanel panel_main;
JPanel panel_phbook;
JPanel panel_numb;
JPanel panel_grp;
JButton btn_main_phb;
JButton btn_main_name;
JButton btn_main_numb;
JButton btn_main_grp;
JTextArea ta_name_serch;
TextField tf_name_input;
JButton btn_name_search;
JButton btn_name_cancel;
JButton btn_name_modify;
JButton btn_name_del;
JButton btn_name_send;
JTextArea ta_numb_serch;
TextField tf_numb_input;
JButton btn_numb_search;
JButton btn_numb_cancel;
JButton btn_numb_modify;
JButton btn_numb_del;
JButton btn_numb_send;
JButton btn_grp_search;
JButton btn_grp_cancel;
JButton btn_grp_modify;
JButton btn_grp_del;
JButton btn_grp_send;
private JTable table;
public static void main(String[] args)
{
PhoneBook frame = new PhoneBook();
}
public PhoneBook()
{
colName = new String[3];
panel_main = new JPanel();
panel_main.setLayout(new GridLayout());
btn_main_phb = new JButton("phonbook");
btn_main_name = new JButton("name");
btn_main_numb = new JButton("number");
btn_main_grp = new JButton("grp");
btn_main_phb.addActionListener(this);
btn_main_name.addActionListener(this);
btn_main_numb.addActionListener(this);
btn_main_grp.addActionListener(this);
panel_main.add(btn_main_phb);
panel_main.add(btn_main_name);
panel_main.add(btn_main_numb);
panel_main.add(btn_main_grp);
// table = new JTable();
// table.setColumnSelectionAllowed(true);
// panel_main.add(table);
// table.set
panel_phbook = new JPanel();
panel_phbook.setLayout(new GridLayout());
// panel_phbook.add(btn_main_phb);
// panel_phbook.add(btn_main_name);
// panel_phbook.add(btn_main_numb);
// panel_phbook.add(btn_main_grp);
btn_name_search = new JButton("Serch");
btn_name_cancel = new JButton("Serch Cancel");
btn_name_modify = new JButton("Modi");
btn_name_del = new JButton("del");
btn_name_send = new JButton("sms send");
TextField tf_name_input = new TextField();
panel_phbook.add(tf_name_input);
panel_phbook.add(btn_name_search);
btn_name_search.addActionListener(this);
//
panel_numb = new JPanel();
panel_grp = new JPanel();
//getContentPane().setLayout(BorderLayout());
getContentPane().setLayout(new BorderLayout());
setLocation(500, 400);
getContentPane().add(panel_main);
setSize(650,150);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setVisible(true);
}
@Override public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
if(e.getSource().equals(btn_main_phb))
{
JFrame frame2 = new JFrame();
frame2.getContentPane().add(panel_phbook);
frame2.setLocation(400, 300);
frame2.setSize(500,400);
setDefaultCloseOperation(EXIT_ON_CLOSE);
frame2.setVisible(true);
}
else if(e.getSource().equals(btn_main_name))
{
}
else if(e.getSource().equals(btn_main_numb))
{
}
else if(e.getSource().equals(btn_main_grp))
{
}
else if(e.getSource().equals(btn_name_search))//this is the problem
{
System.out.println(tf_name_input.getText());
}
}
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at PhoneBook.actionPerformed(PhoneBook.java:166) at javax.swing.AbstractButton.fireActionPerformed(Unknown Source) at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.setPressed(Unknown Source) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source) at java.awt.Component.processMouseEvent(Unknown Source) at javax.swing.JComponent.processMouseEvent(Unknown Source) at java.awt.Component.processEvent(Unknown Source) at java.awt.Container.processEvent(Unknown Source) at java.awt.Component.dispatchEventImpl(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source) at java.awt.Lightwe ightDispatcher.dispatchEvent(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Window.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$200(Unknown Source) at java.awt.EventQueue$3.run(Unknown Source) at java.awt.EventQueue$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue$4.run(Unknown Source) at java.awt.EventQueue$4.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread .pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
The reason you are getting this problem is because you have created a new local variable with the same name as one of your class member variables:
TextField tf_name_input = new TextField();
instead of:
tf_name_input = new TextField();