JTextField and Drawing Images Does Not Work

Question

So I have the following code, and whenever I press the square tool button it should draw a square where the JTextFields say it should be. But for some reason the JTextField values don't work, and the square cannot be drawn... Here is the square code, and the JTextField:

Initialization of the JTextFields

        squareX = new JTextField(3);
        squareY = new JTextField(3);
        squareW = new JTextField(3);
        squareH = new JTextField(3);

The ActionListeners:

        squareX.addActionListener(listener);
        squareY.addActionListener(listener);
        squareW.addActionListener(listener);
        squareH.addActionListener(listener);

This is where I set their values to the text:

        x = Integer.parseInt(op.squareX.getText());
        y = Integer.parseInt(op.squareY.getText());
        w = Integer.parseInt(op.squareW.getText());
        h = Integer.parseInt(op.squareH.getText());
        g.fillRect(x,y,w,h);

And if it matters here is what the error says

Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: ""
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
    at java.lang.Integer.parseInt(Integer.java:470)
    at java.lang.Integer.parseInt(Integer.java:499)
    at com.theDevCorner.Game$GridPane.paintComponent(Game.java:155)
    at javax.swing.JComponent.paint(JComponent.java:1037)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5106)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4890)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:814)
    at javax.swing.RepaintManager$3.run(RepaintManager.java:802)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:802)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:745)
    at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:725)
    at javax.swing.RepaintManager.access$1000(RepaintManager.java:46)
    at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1684)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:708)
    at java.awt.EventQueue.access$400(EventQueue.java:82)
    at java.awt.EventQueue$2.run(EventQueue.java:669)
    at java.awt.EventQueue$2.run(EventQueue.java:667)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:678)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

Answer 1

The constructor JTextField(int) specifys the number of columns rather than the initial value. Therefore the JTextComponent's text value is still empty when passed to Integer#parseInt. Therefore you can use the constructor that specifys the initial value instead:

squareX = new JTextField("3");
squareY = new JTextField("3");
squareW = new JTextField("3");
squareH = new JTextField("3");