Text field does not realize its being called

[idlackage]

I'm not sure if this is because I'm initializing the textfields inside a method instead of the constructor, but in any case I cannot get anything to be printed out no matter which field I type into.

public class TransformWindow extends JFrame {
  
  private JTextField x1_textField;
  private JTextField x2_textField;
  private JTextField y1_textField;
  private JTextField y2_textField;
  
  private Shape shape[];
  private int shapeX1;
  private int shapeX2;
  private int shapeY1;
  private int shapeY2;
  
  private PaintCanvas canvas;
  
  private TextHandler handler;
  
  public TransformWindow( PaintCanvas canvas ) {
    
    super( "Tranform shape" );
    setLayout( new GridLayout(2,2,10,5) );
    
    this.canvas = canvas;
    
    shape = canvas.getShape();
    shapeX1 = shape[0].getX1();
    shapeX2 = shape[0].getX2();
    shapeY1 = shape[0].getY1();
    shapeY2 = shape[0].getY2();
    
    newPanel( "x1", x1_textField, Integer.toString(shapeX1) );
    newPanel( "x2", x2_textField, Integer.toString(shapeX2) );
    newPanel( "y1", y1_textField, Integer.toString(shapeY1) );
    newPanel( "y2", y2_textField, Integer.toString(shapeY2) );
    
    canvas.setShape( shape );
    
    handler = new TextHandler();
    
  }
  
  private void newPanel( String text, JTextField textField, String coords ) {
    
    JLabel label = new JLabel( text );
    textField = new JTextField();
    JPanel panel = new JPanel();
    panel.setLayout( new BorderLayout(5,10) );
    panel.add( label, BorderLayout.WEST );
    panel.add( textField, BorderLayout.CENTER );
    
    textField.addActionListener( handler );
    textField.setText( coords );
    
    add( panel );
    
  }
  
  // Private inner class for text event handling
  private class TextHandler implements ActionListener {
    public void actionPerformed( ActionEvent event ) {
      
      // Determine the text field in which values were inputted
      if( event.getSource() == x1_textField ) {
        shape[0].setX1( Integer.parseInt(x1_textField.getText()) );
        System.out.println( "test output string" );
      } else if( event.getSource() == x2_textField ) {
        shape[0].setX2( Integer.parseInt(event.getActionCommand()) );
      } else if( event.getSource() == y1_textField ) {
        shape[0].setY1( Integer.parseInt(event.getActionCommand()) );
      } else if( event.getSource() == y2_textField ) {
        shape[0].setY2( Integer.parseInt(event.getActionCommand()) );
      }
      
    }
  }
  
}

Thanks for any help.

[PhHein]

public TransformWindow( PaintCanvas canvas )

looks suspicious, never ever mix AWT and Swing!

Your JTextField References are all null, so your check for

event.getSource()

will always fail. Remember that Java is pass by value.

[Tolls]

// Your call to newPanel.
    newPanel( "y2", y2_textField, Integer.toString(shapeY2) );
 
// newPanel() itself
  private void newPanel( String text, JTextField textField, String coords ) {
// do stuff
    textField = new JTextField();
// do more stuff
  }

As PhHein says, Java is pass by value.
That is, that "new JTextField()" call is not doing anything to the y2_textField variable, which will still be pointing at null.

[idlackage]

Thanks to both for your replies! I moved every command regarding the textfields to the constructor and it worked, but is there a more efficient way to go about this?

looks suspicious, never ever mix AWT and Swing!

This was never talked about in class so I have no idea why this is. Is it bad form like using a switch statement, or just something wrong?

[Tolls]

You could still use that method, but initialise the JTextField beforehand, and not in the method.
So:

    y2_textField = new JTextField();
    newPanel( "y2", y2_textField, Integer.toString(shapeY2) );

[PhHein]

Thanks to both for your replies! I moved every command regarding the textfields to the constructor and it worked, but is there a more efficient way to go about this?



This was never talked about in class so I have no idea why this is. Is it bad form like using a switch statement, or just something wrong?

Hard to tell, I don't know what a PaintCanvas is. Mixing "heavyweight and lightweight components" causes some strange GUI effects, search on Google, there are some articles about it.