sysntax error?

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  • nu b
    #1

    sysntax error?

    Hello all. I am new and I am having a tough time spotting my error here. The
    idea is to produce an applet that will have a JButton which I can push to
    display the string myName. Later I will make it so that it will chage the
    font size and style, but for now I can't even get it to display the String.
    It compiles fine but when I launch it in the browser or with the
    appletviewer, it shows the button and nothing happens when I click it. Can
    you see anything wrong with the way i set this up? Thanks in advance.

    import javax.swing.*;
    import java.awt.*;
    import java.awt.event. *;

    public class JBlueGrey extends JApplet implements ActionListener
    {
    String myName = new String("Randy") ;
    JButton btnPush = new JButton("Push") ;
    Font firstFont = new Font("Helvetica ", Font.ITALIC, 8);

    public void init()
    {
    Container con = getContentPane( );
    con.setLayout(n ew FlowLayout());
    con.add(btnPush );
    btnPush.addActi onListener(this );
    }

    public void actionPerformed (ActionEvent e)
    {
    Object source = e.getSource();
    if (source == btnPush)
    {
    Graphics draw = getGraphics();
    draw.setFont(fi rstFont);
    draw.drawString (myName, 10, 100);
    }

    }

    }


    Tags: None
    • Folke Bengtsson
      #2
      Re: sysntax error?

      The modified code works.
      Added setSize in the JApplets init method.
      Added a main method for test, and call init from that method.

      Your approach for drawing could be better.
      implement a method called
      public void paint(Graphics g){
      g.drawString("r andy", x, y);
      }

      and do all your drawing in that method (it is called from the
      awt-thread, for all components that are to be drawn).

      By implementing paint(..), we are telling awt to do the painting of the
      component. paint is overridden to be handled correctly by the
      swing-thread.

      Don't mix awt and swing.


      import javax.swing.*;
      import java.awt.*;
      import java.awt.event. *;

      public class JBlueGrey extends JApplet implements ActionListener
      {
      String myName = new String("Randy") ;
      JButton btnPush = new JButton("Push") ;
      Font firstFont = new Font("Helvetica ", Font.ITALIC, 8);

      public void init()
      {
      Container con = getContentPane( );
      con.setLayout(n ew FlowLayout());
      con.add(btnPush );
      btnPush.addActi onListener(this );
      //added
      setSize(100, 100);
      //to here
      }

      public void actionPerformed (ActionEvent e)
      {
      Object source = e.getSource();
      if (source == btnPush)
      {
      Graphics draw = getGraphics();
      draw.setFont(fi rstFont);
      draw.drawString (myName, 10, 100);
      }

      }
      //added
      public static void main(String[] args){
      JFrame jf = new JFrame("etst");

      JBlueGrey jApplet = new JBlueGrey();

      jApplet.init();

      jf.setContentPa ne(jApplet);
      jf.pack();
      jf.setVisible(t rue);
      }
      //to here
      }



      In article <aDHkb.30727$gi 2.28720@fed1rea d01>, nu b
      <yrnuthin@yahoo .com> wrote:
      [color=blue]
      > import javax.swing.*;
      > import java.awt.*;
      > import java.awt.event. *;
      >
      > public class JBlueGrey extends JApplet implements ActionListener
      > {
      > String myName = new String("Randy") ;
      > JButton btnPush = new JButton("Push") ;
      > Font firstFont = new Font("Helvetica ", Font.ITALIC, 8);
      >
      > public void init()
      > {
      > Container con = getContentPane( );
      > con.setLayout(n ew FlowLayout());
      > con.add(btnPush );
      > btnPush.addActi onListener(this );
      > }
      >
      > public void actionPerformed (ActionEvent e)
      > {
      > Object source = e.getSource();
      > if (source == btnPush)
      > {
      > Graphics draw = getGraphics();
      > draw.setFont(fi rstFont);
      > draw.drawString (myName, 10, 100);
      > }
      >
      > }
      >
      > }[/color]

        Comment

        • Folke Bengtsson
          #3
          Re: sysntax error?

          In article <20102003105826 7530%Folke.Beng tsson@frobozz.s e>, Folke
          Bengtsson <Folke.Bengtsso n@frobozz.se> wrote:
          [color=blue]
          > The modified code works.
          > Added setSize in the JApplets init method.
          > Added a main method for test, and call init from that method.
          >
          > Your approach for drawing could be better.
          > implement a method called
          > public void paint(Graphics g){[/color]
          hmm...sorry.. should probably be
          public void paintComponent( Graphics g){..}

          I think I'm mixing awt and swing.
          [color=blue]
          > g.drawString("r andy", x, y);
          > }
          >
          > and do all your drawing in that method (it is called from the
          > awt-thread, for all components that are to be drawn).
          >
          > By implementing paint(..), we are telling awt to do the painting of the
          > component. paint is overridden to be handled correctly by the
          > swing-thread.
          >
          > Don't mix awt and swing.
          >
          >
          > import javax.swing.*;
          > import java.awt.*;
          > import java.awt.event. *;
          >
          > public class JBlueGrey extends JApplet implements ActionListener
          > {
          > String myName = new String("Randy") ;
          > JButton btnPush = new JButton("Push") ;
          > Font firstFont = new Font("Helvetica ", Font.ITALIC, 8);
          >
          > public void init()
          > {
          > Container con = getContentPane( );
          > con.setLayout(n ew FlowLayout());
          > con.add(btnPush );
          > btnPush.addActi onListener(this );
          > //added
          > setSize(100, 100);
          > //to here
          > }
          >
          > public void actionPerformed (ActionEvent e)
          > {
          > Object source = e.getSource();
          > if (source == btnPush)
          > {
          > Graphics draw = getGraphics();
          > draw.setFont(fi rstFont);
          > draw.drawString (myName, 10, 100);
          > }
          >
          > }
          > //added
          > public static void main(String[] args){
          > JFrame jf = new JFrame("etst");
          >
          > JBlueGrey jApplet = new JBlueGrey();
          >
          > jApplet.init();
          >
          > jf.setContentPa ne(jApplet);
          > jf.pack();
          > jf.setVisible(t rue);
          > }
          > //to here
          > }
          >
          >
          >
          > In article <aDHkb.30727$gi 2.28720@fed1rea d01>, nu b
          > <yrnuthin@yahoo .com> wrote:
          >[color=green]
          > > import javax.swing.*;
          > > import java.awt.*;
          > > import java.awt.event. *;
          > >
          > > public class JBlueGrey extends JApplet implements ActionListener
          > > {
          > > String myName = new String("Randy") ;
          > > JButton btnPush = new JButton("Push") ;
          > > Font firstFont = new Font("Helvetica ", Font.ITALIC, 8);
          > >
          > > public void init()
          > > {
          > > Container con = getContentPane( );
          > > con.setLayout(n ew FlowLayout());
          > > con.add(btnPush );
          > > btnPush.addActi onListener(this );
          > > }
          > >
          > > public void actionPerformed (ActionEvent e)
          > > {
          > > Object source = e.getSource();
          > > if (source == btnPush)
          > > {
          > > Graphics draw = getGraphics();
          > > draw.setFont(fi rstFont);
          > > draw.drawString (myName, 10, 100);
          > > }
          > >
          > > }
          > >
          > > }[/color][/color]

            Comment

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