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POcannot start swing timer
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  1. POcannot start swing timer
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    copied!<p>I'm trying to make a Swing Timer that is executes when I press a button but never starts. My code is:</p> <pre><code>public class prueba extends JFrame { java.util.Date date= new java.util.Date(); private JPanel contentPane; Timer timero; ........ public prueba() { .......... timero = new Timer(1000, new ActionListener() { public void actionPerformed(ActionEvent e) { System.out.println("otra vez....uauuauauaua"); } }); btnIniciar.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { timero.start(); ............... </code></pre> <p>Could you help me please? Thanks and sorry for my english!</p> <p>When I do these I have an error:</p> <pre><code>public class prueba extends JFrame { java.util.Date date= new java.util.Date(); private JPanel contentPane; Timer timero; public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { try { prueba frame = new prueba(); frame.setVisible(true); } catch (Exception e) { e.printStackTrace(); } } }); } public prueba() { final WebManager web = new WebManager("user","pass","http://www.spanishtracker.com/login.php"); //web.EnableDebug(); web.doLogin(); web.getCookies; ..... contentPane.add(txtSalida, gbc_txtSalida); timero.start(); </code></pre> <p>it gives me an error:</p> <pre><code>java.lang.NullPointerException at prueba.&lt;init&gt;(prueba.java:216) at prueba$1.run(prueba.java:56) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$400(Unknown Source) at java.awt.EventQueue$2.run(Unknown Source) These lines are: 216 timero.start(); 56 prueba frame = new prueba(); </code></pre>
 

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