how to choose the field where last JTextField

[aledara]

i have a problem in first Java application ; there is an image for my calculator

how can i set the number on the field i choose when i press on it by using mouse , is there an option to get the right field .....i just build zero buttons for test


import java.awt.*;

import java.awt.event.*;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;


public class calc extends JFrame implements ActionListener {
JTextField num1 = new JTextField(" 1 ",3);
JTextField num3 = new JTextField(" 1 ",3);
JTextField num2 = new JTextField(" 1 ",3);
JTextField num4 = new JTextField(" 1 ",3);
JTextField num = new JTextField(" 1 ");



JLabel answer = new JLabel("0.22");
JLabel symbol = new JLabel("+");
JLabel equals = new JLabel("=");
JLabel simplification = new JLabel(" ");
JLabel status = new JLabel(" ");

JButton addButton = new JButton(" + ");
JButton subButton = new JButton(" - ");
JButton multButton = new JButton(" X ");
JButton divButton = new JButton(" ÷ ");
JButton zero = new JButton(" 0 ");
JButton one = new JButton(" 1 ");
JButton two = new JButton(" 2 ");
JButton three = new JButton(" 3 ");
JButton four = new JButton(" 4 ");
JButton five = new JButton(" 5 ");
JButton sex = new JButton(" 6 ");
JButton seven = new JButton(" 7 ");
JButton eight = new JButton(" 8 ");
JButton nine = new JButton(" 9 ");


public calc()
{

JPanel fields = new JPanel(new FlowLayout());
fields.add(num1);
fields.add(num4);
fields.add(symbol);
fields.add(num2);
fields.add(num3);
fields.add(equals);
fields.add(answer);
fields.add(status);
fields.add(simplification);

JPanel buttons = new JPanel(new FlowLayout());

buttons.setLayout(new GridLayout(0, 4, 5, 5));// array of buttons
// (row,cols,v-space,h_space);

buttons.add(divButton);
buttons.add(one);
buttons.add(two);
buttons.add(three);
buttons.add(multButton);
buttons.add(four);
buttons.add(five);
buttons.add(sex);
buttons.add(subButton);
buttons.add(seven);
buttons.add(eight);
buttons.add(nine);

//num1.setBounds(23,344, 200,28);//hadool men el calcolator el tanyeh
//num1.setBackground(Color.black);
//num1.setForeground(Color.green);

JPanel numbers = new JPanel(new GridLayout(2,1,2,2)); //FlowLayout

numbers.add(addButton);
numbers.add(zero);


// num1.setPreferredSize(new Dimension(50, 50));


getContentPane().setLayout(new BorderLayout(2,2));
getContentPane().add("North", fields);
getContentPane().add("Center", buttons);
getContentPane().add("South", numbers);

zero.addActionListener(this);
addButton.addActionListener(this);
subButton.addActionListener(this);
multButton.addActionListener(this);
divButton.addActionListener(this);

num.requestFocus(true);
num.requestFocus();




pack();
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
System.gc();
}


public void actionPerformed(ActionEvent e)
{


if (e.getSource().equals(zero))
{






}

}




public static void main(String args[]) {
new calc();
}
}

[Fubarable]

I suppose you want to add a FocusListener to your JTextFields and use it to keep track of which field was last one to have focus. This can be done in the focusGained method where you set a reference to the current JTextField (obtained by calling getSource on the FocusEvent object) to a class variable that may hold a reference to this field, but I'm not quite sure of the overall gist of your GUI.

Much luck!

[aledara]

i dont know how to add FocusListener please help me

[Fubarable]

i dont know how to add FocusListener please help me

The tutorials can show you. Please have a look and give it a try.

How to Write a Focus Listener (The Java™ Tutorials > Creating a GUI With JFC/Swing > Writing Event Listeners)

Luck!

[aledara]

thank you man you are great i will try

[aledara]

this the code i try to add many thing but nothing success help me

package sallal.com.java.array;

import java.awt.*;

import java.awt.event.*;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class calc extends JFrame implements ActionListener ,FocusListener 
{
	
	JTextArea display = new JTextArea();
	
	JTextField num1 = new JTextField("   1  ",3);
	JTextField num3 = new JTextField("   1  ",3);
	JTextField num2 = new JTextField("   1  ",3);
	JTextField num4 = new JTextField("   1  ",3);
	
	JTextField num = new JTextField("    1   ");
	

	JLabel answer = new JLabel("0.22");
	JLabel symbol = new JLabel("+");
	JLabel equals = new JLabel("=");
	JLabel simplification = new JLabel("         ");
	JLabel status = new JLabel("         ");

	JButton addButton = new JButton(" + ");
	JButton subButton = new JButton(" - ");
	JButton multButton = new JButton(" X ");
	JButton divButton = new JButton(" ÷ ");
	JButton zero = new JButton(" 0 ");
	JButton one = new JButton(" 1 ");
	JButton two = new JButton(" 2 ");
	JButton three = new JButton(" 3 ");
	JButton four = new JButton(" 4 ");
	JButton five = new JButton(" 5 ");
	JButton sex = new JButton(" 6 ");
	JButton seven = new JButton(" 7 ");
	JButton eight = new JButton(" 8 ");
	JButton nine = new JButton(" 9 ");


	public calc() 
	{
		
		JPanel fields = new JPanel(new FlowLayout());
		fields.add(num1);
		fields.add(num4);
		fields.add(symbol);
		fields.add(num2);
		fields.add(num3);
		fields.add(equals);
		fields.add(answer);
		fields.add(status);
		fields.add(simplification);
		
		JPanel buttons = new JPanel(new FlowLayout());

		buttons.setLayout(new GridLayout(0, 4, 5, 5));// array of buttons
													  // (row,cols,v-space,h_space);
		
		buttons.add(divButton);
		buttons.add(one);
		buttons.add(two);
		buttons.add(three);
		buttons.add(multButton);
		buttons.add(four);
		buttons.add(five);
		buttons.add(sex);
		buttons.add(subButton);
		buttons.add(seven);
		buttons.add(eight);
		buttons.add(nine);
		
		//num1.setBounds(23,344, 200,28);//hadool men el calcolator el tanyeh
		//num1.setBackground(Color.black);
		//num1.setForeground(Color.green);
		
		JPanel numbers = new JPanel(new GridLayout(2,1,2,2));	//FlowLayout
		
		numbers.add(addButton);
		numbers.add(zero);

		
		
		getContentPane().setLayout(new BorderLayout(2,2));
		getContentPane().add("North", fields);
		getContentPane().add("Center", buttons);
		getContentPane().add("South", numbers);

		zero.addActionListener(this);
		addButton.addActionListener(this);
		subButton.addActionListener(this);
		multButton.addActionListener(this);
		divButton.addActionListener(this);
		
		
		num1.addFocusListener(this);
		num2.addFocusListener(this);
		num3.addFocusListener(this);
		num4.addFocusListener(this);
	
		
		display.setEditable(false);
		display.setRequestFocusEnabled(false);
        
        display.addFocusListener(this);



		
		pack();
		setVisible(true);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		System.gc();
	}
	

	public void actionPerformed(ActionEvent e) 
	{
	 if (e.getSource().equals(zero)) 
		{	
			
			//num=JTextField.mouseClicked();
			//num2.setText("    0    ");
		//	num.setText("    78    ");
			
		}

	}

	
	 public void focusGained(FocusEvent e)
	 {
		
	 }

	 public void focusLost(FocusEvent e) 
		{
		    	;
		}

	 
	
	public static void main(String args[]) {
		new calc();
	}


	
}

[Fubarable]

Again, I'm not 100% sure I understand what you're trying to do, but if it is to place button press text into the JTextField with the most recent focus, then give your class a JTextField variable that will hold a reference to the last focused JTextField:

public class FocusTest {
   //......
   private JTextField fieldWithLastFocus = null;

And then give the class a FocusListener, and in the focusGained method set the variable above to refer to the JTextField that just gained focus. I prefer to use a private inner class for this:

   private class MyFocusListener extends FocusAdapter {
      @Override
      public void focusGained(FocusEvent e) {
         fieldWithLastFocus = (JTextField) e.getSource();
      }
   }

Then create an instance of the focus listener and add it to your JTextFields.

For example:

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

public class FocusTest {
   public static final String[][] BUTTON_STRS = {
      {"7", "8", "9", "/"}, 
      {"4", "5", "6", "*"},
      {"1", "2", "3", "-"}, 
      {"0", ".", "+", "="}};

   private JPanel mainPanel = new JPanel();
   private JTextField[] textFields = new JTextField[4];
   private JButton[][] buttons = new JButton[BUTTON_STRS.length][BUTTON_STRS[0].length];
   private JTextField fieldWithLastFocus = null;

   public FocusTest() {
      JPanel topPanel = new JPanel(new GridLayout(1, 0, 5, 0));
      FocusListener myFocusListener = new MyFocusListener();
      for (int i = 0; i < textFields.length; i++) {
         textFields[i] = new JTextField(5);
         textFields[i].addFocusListener(myFocusListener);
         topPanel.add(textFields[i]);
      }

      JPanel buttonPanel = new JPanel(new GridLayout(4, 4, 5, 5));
      ActionListener myBtnListener = new MyButtonListener();
      for (int row = 0; row < buttons.length; row++) {
         for (int col = 0; col < buttons[row].length; col++) {
            buttons[row][col] = new JButton(BUTTON_STRS[row][col]);
            buttons[row][col].addActionListener(myBtnListener);
            buttons[row][col].setFocusable(false);
            buttonPanel.add(buttons[row][col]);
         }
      }

      mainPanel.setLayout(new BorderLayout(5, 5));
      mainPanel.add(topPanel, BorderLayout.NORTH);
      mainPanel.add(buttonPanel, BorderLayout.CENTER);
      int eb = 5;
      mainPanel.setBorder(BorderFactory.createEmptyBorder(eb, eb, eb, eb));
   }

   public JPanel getMainPanel() {
      return mainPanel;
   }

   private class MyFocusListener extends FocusAdapter {
      @Override
      public void focusGained(FocusEvent e) {
         fieldWithLastFocus = (JTextField) e.getSource();
      }
   }

   private class MyButtonListener implements ActionListener {
      public void actionPerformed(ActionEvent ae) {
         String actCommand = ae.getActionCommand();
         
         // if a number or . key pressed
         if ("1234567890.".contains(actCommand)) {
            
            // if a text field has had focus ever
            if (fieldWithLastFocus != null) {
               // get jtextfield's string
               String text = fieldWithLastFocus.getText();
               
               // append the button's text to it:
               text += actCommand;
               
               // and insert it into the JTextField
               fieldWithLastFocus.setText(text);
            }
         }
      }
   }

   private static void createAndShowUI() {
      JFrame frame = new JFrame("FocusTest");
      frame.getContentPane().add(new FocusTest().getMainPanel());
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      java.awt.EventQueue.invokeLater(new Runnable() {
         public void run() {
            createAndShowUI();
         }
      });
   }
}

Also, please read my first signature link on how to use code tags as they make your posted code a lot more readable. I've added them to your post above so you can see the difference they make.

Luck.

[aledara]

thats work fine no word can describe how can i thank you

[Fubarable]

Glad it helped. Good luck with your project.