Beginner question for java appelets regarding positioning.

Question

I am creating a java appelet, and I am having issues positioning labels, text boxes , buttons. Is there a way I can specify where each is positioned?
Thank you!
for example here is my code:
import java.awt.*;
import java.applet.Applet;
import java.awt.event.*;
public class AdditionOfFractions extends Applet implements ActionListener {
    Label Num1Lbl = new Label("num1");
    Label Num2Lbl = new Label("num2");
    Label Den1Lbl = new Label("den1");
    Label Den2Lbl = new Label("den2");
    Label ResultLbl = new Label("Result");
    TextField Num1Text = new TextField(4);
    TextField Num2Text = new TextField(4);
    TextField Den1Text = new TextField(4);
    TextField Den2Text = new TextField(4);
    TextField ResultText = new TextField(4);
    Button ComputeBtn  = new Button("Compute");
    Button ExitBtn  = new Button("Exit");
    public void actionPerformed(ActionEvent thisEvent)throws NumberFormatException {
        if(ComputeBtn.hasFocus()){
            System.out.println("test");
            int num1 = Integer.parseInt(Num1Text.getText());
            int num2 = Integer.parseInt(Num2Text.getText());
            int den1 = Integer.parseInt(Den1Text.getText());
            int den2 = Integer.parseInt(Den2Text.getText());
            int newDen = 0;
            if(den1 != den2){
    public void init()
        //initialise
        ResultText.setEditable(false);
        ComputeBtn.addActionListener(this);
        ExitBtn.addActionListener(this);
        //add components
        add(Num1Lbl);
        add(Num1Text);
        add(Den1Lbl);
        add(Den1Text);
        add(Num2Lbl);
        add(Num2Text);
        add(Den2Lbl);
        add(Den2Text);
        add(ResultLbl);
        add(ResultText);
        add(ComputeBtn);
        add(ExitBtn);
}

Answer 1

797737 wrote:
I am creating a java appelet, and I am having issues positioning labels, text boxes , buttons. Is there a way I can specify where each is positioned?Definitely, for your simple Applet you'll probably just want to use a <tt>java.awt.GridLayout</tt>. This will effectively position all your components in a grid pattern that you set in the contructor.
//make a grid 4 rows, 2 columns
GridLayout gridLayout = new GridLayout(4, 2);Then you'll need to set this for the Applet like so:
pubic void init(){
  //initial your components as usual
  setLayout(gridLayout);
  //add components as usual;
}Now 37, you don't want the <tt>actionPerformed()</tt> method to throw any Exceptions. Instead put your code inside a try/catch block:
public void actionPerformed(ActionEvent ae)
  int num1, num2, den1, den2;
  try {
    num1 = Integer.parseInt(Num1Text.getText());
    num2 = Integer.parseInt(Num2Text.getText());
    den1 = Integer.parseInt(Den1Text.getText());
    den2 = Integer.parseInt(Den2Text.getText());
  catch(NumberFormatException)
    //provide DEFAULT VALUES HERE;
}37, try to use the <tt>EventObject.getSource()</tt>, or <tt>ActionEvent.getActionCommand()</tt>.
public void actionPerformed(ActionEvent ae) {
  //Choose one of the following lines
  //line 2 is probably a better choice here
  Button button = (Button)ae.getSource();
  String actionCommand = ae.getActionCommand();
  if(actionCommand.equals("Compute"))
    //try/catch block here
    //compute here
    //set results
    // OR create a compute() that
    // includes all three lines above
}Now OP, I have a question for you. Do you see a way to LIMIT the values of <tt>num1, num2, den1, den2</tt> so that your program is safe to run -- so that the compute formula does not throw any ArithmeticExceptions?