Develop Reference

How to re-size JButton

I've bee teaching myself java and following along with the problems in the book. I'm trying to make a display for my calculator. In the example(I did not attach this) the buttons were a smaller size than what mine are and I can't figure out how to reformat them. I tried using the dimension class but it had no affect. Also, I can't get my text at the top of the calculator to align left.
Here is my code:
public class Calculator extends JFrame {
public Calculator() {
setTitle("Calculator");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setSize(300, 300);
setLayout(new BorderLayout());
JPanel numberPanel = new JPanel();
add(numberPanel, BorderLayout.CENTER);
numberPanel.setLayout(new GridLayout(4, 3, 3, 3));
for(int i = 1; i < 10; i++) {
JButton button = new JButton(String.valueOf(i));
numberPanel.add(button);
}
JButton zero = new JButton("" + 0);
JButton dot = new JButton(".");
JButton clear = new JButton("C");
numberPanel.add(zero);
numberPanel.add(dot);
numberPanel.add(clear);
JPanel keyPanel = new JPanel();
add(keyPanel, BorderLayout.EAST);
keyPanel.setLayout(new GridLayout(4, 1, 3, 3));
JButton plus = new JButton("+");
JButton minus = new JButton("-");
JButton times = new JButton("*");
JButton divide = new JButton("/");
keyPanel.add(plus);
keyPanel.add(minus);
keyPanel.add(times);
keyPanel.add(divide);
JPanel equalsPanel = new JPanel();
add(equalsPanel, BorderLayout.SOUTH);
equalsPanel.setLayout(new GridLayout(1, 1));
JButton equals = new JButton("=");
equalsPanel.add(equals);
JPanel textPanel = new JPanel();
add(textPanel, BorderLayout.NORTH);
JTextField inputBox = new JTextField("0.0");
inputBox.setHorizontalAlignment(JTextField.LEFT);
inputBox.setEditable(false);
Font font = new Font("MonoSpaced", Font.BOLD, 20);
inputBox.setFont(font);
textPanel.add(inputBox);
setVisible(true);
}
public static void main(String[] args) {
new Calculator();
}
}
Imports were left off for brevity

GridLayout will laugh at you when you try and set a dimension. It does respect preferred sizes. You should select a layout manager that will respect preferred sizes. Or you can simply pack() (after you add all your components) your frame instead of setSize() and all the components preferred sizes will kick in. (Disclaimer - because of GridLayout though, if you try and resize the frame after that, you components will resize again)
See more at How to use Layout Managers. For a quick view of which layout managers respect preferred sizes and which ones don't, have a look at this post.
A common approach is to nest panels with different layout managers also, as seen here
UPDATE
As mentioned preciously, you should just call pack on the frame instead of set size. With your current code, this would cause the frame to be very small because of the preferred sizes of the components. If you want the buttons to have a bigger preferred size, you can set the font to a bigger font and/or use button.setMargins(new Insets(w,x,y,x)); to make the margins bigger. But it is preferred to pack the frame.

I would recommend using the Window Builder add-on if you’re using Eclipse. This tool will help you with many aspects of Swing. Learn by doing.
WindowBuilder Dowload Link

Is it possible to implement scrollbar in Jframe without Jpanel?

I've written a long code involving several frames using only JFrame, and now I need a scrollbar for one of the frames. It seems like the only way to use JScrollPane is with JPanel, but I dont want to rewrite everything, is there a way?
frames[2] = new JFrame("Title");
frames[2].setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);//EXIT_ON_CLOSE
frames[2].setContentPane(new JLabel(new ImageIcon("/Users/mac/Downloads/bg.000.jpg")));
frames[2].setLayout(new BorderLayout());
frames[2].setLayout(new FlowLayout());
frames[2].setResizable(true);
frames[2].setSize(750,433);
label[4] = new JLabel (" Search : ", JLabel.CENTER);
label[4].setFont(new Font("Serif", Font.ITALIC, 16));
label[4].setForeground(Color.BLACK);// font color
frames[2].add(label[4]);
TextField[2]= new JTextField ("Enter name", 15);
TextField[2].setFont(font);
frames[2].add(TextField[2]);
This is the frame (frame[2]) that I would like the scrollbar to be used in.

JFrame layout with radio buttons

This is my code:
frame2 = new JFrame("Confirmation");
frame2.setLayout(new BorderLayout());
JRadioButton y,n,c;
panel = new JPanel();
ButtonGroup buttonGroup = new ButtonGroup();
y = new JRadioButton("Add");
buttonGroup.add(y);
panel.add(y);
n = new JRadioButton("Update");
buttonGroup.add(n);
panel.add(n);
c = new JRadioButton("Delete");
buttonGroup.add(c);
panel.add(c);
y.setSelected(true);
b1=new JButton();
b1.setBounds(300,100,2,2);
b1.setIcon(new ImageIcon(searchresult.class.getResource("/images/yes.png")));
b2=new JButton();
b2.setBounds(100,10,2,2);
b2.setIcon(new ImageIcon(searchresult.class.getResource("/images/no.png")));
panel.add(b1);
panel.add(b2);
frame2.add(panel);
frame2.setSize(182,150);
frame2.setVisible(true);
Right now this gives me the following output
whereas I want this
with an increased width but I am not able to do it..Could anyone provide me with further details that could help me

JPanel uses a FlowLayout by default, which, as the name suggests, layouts out components one after the after, in a flow...
Two choices. Use a compound layout, using BorderLayout as the base, create JPanel that uses a GridLayout for the radio buttons (using 0 rows and 1 column), add this to the CENTER position of the base panel.
Create a second JPanel using a FlowLayout and your buttons to it. Add this to the SOUTH position of the base pane.
Second choice is to use a GridBagLayout
Take a look at Laying out Components within a Container for more details

Button inside text box

My code shows a button inside a textbox, but when the input value changes, the size of the text box also changes. That I don't like. Is there any solution such that the textbox size remains fixed? Or any other idea on how to create a button inside textbox?
The following is my code:
JPanel panel = new JPanel();
panel.setLayout( new FlowLayout(FlowLayout.CENTER, 0, 0) );
panel.add(textField);
panel.add(button);
panel.setBackground( textField.getBackground() );
panel.setBorder( textField.getBorder() );
textField.setBorder(null);

Try a BorderLayout and add the textfield at BorderLayout.CENTER and the button at BorderLayout.EAST.

I tried your code, and it seemed to work fine for me, with a slight modification. It may be that panel is resizing itself, not textField. Try wrapping panel in another JPanel to force its shape.
JPanel panel = new JPanel();
JPanel outerPanel = new JPanel();
panel.setLayout( new FlowLayout(FlowLayout.CENTER, 0, 0) );
panel.add(textField);
panel.add(button);
panel.setBackground( textField.getBackground() );
panel.setBorder( textField.getBorder() );
textField.setBorder(null);
outerPanel.add(panel);

Your example appears to be the second alternative discussed in the article Component Border. Instead, you may want to install() a ComponentBorder, a third alterative described later in the same article.

Is there any solution such that the textbox size remains fixed?
I'm guessing you are creating the JTextField like:
JTextField textField = new JTextField();
In this case the text field size changes as you add text to it.
Instead you should use:
JTextField textField = new JTextField(10);
and the text field will remain a constant size an hold a minimum of 10 characters before scrolling.

Use a different Layout, or try absolute positioning

How can I set a JPanel maximum or preferred size that uses gridLayout?

I had problem using a very simple frame containing two JPanel.
The problem is on the layout of the Center JPanel that contains four JButton.
How can I set a better size for buttons or directly for JPanel that uses the GridLayout. On the picture the problem:
alt http://img42.imageshack.us/img42/4601/horrible.jpg
!
Here the code: ` JFrame window = new JFrame("Horrible! LOL");
JTextField textField = new JTextField("");
textField.setPreferredSize(new Dimension(200,20));
JPanel textPanel = new JPanel(new FlowLayout(FlowLayout.CENTER));
textPanel.add(textField);
window.add(textPanel, BorderLayout.NORTH);
JButton plus = new JButton("+");
//plus.setPreferredSize(new Dimension(50,50)); nothing would change
JButton minus = new JButton("-");
JButton per = new JButton("x");
JButton divide = new JButton("/");
JPanel prova = new JPanel(new GridLayout(2,2,10,10));
Dimension d = new Dimension(20,20);
prova.setMaximumSize(d); // nothing changed!
prova.add(plus);
prova.add(minus);
prova.add(per);
prova.add(divide);
window.add(prova, BorderLayout.CENTER);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setSize(250,300);
window.setResizable(false);
window.setVisible(true);`
Which is a good solution?
Kind regards

Unfortunately gridlayout doesent respect preferred sizes. But still if you want to stick to grid layout then you can try something like this:
public static JComponent wrap(JComponent comp)
{
JPanel panel = new JPanel();
panel.add(comp);
return panel;
}
And then instead of direclty adding in to prova add like this:
prova.add(wrap(plus));
prova.add(wrap(minus));
prova.add(wrap(per));
prova.add(wrap(divide));
Tested, Works perfect!!
There are other better ways though

That's what happen to me:
It's definitely attached to the upper edge of the grid.
alt text http://img96.imageshack.us/img96/9431/stillnot.jpg
Even if in this case, in the wrap method I can set the preferredSize of buttons/comp, every buttons is on its own edge. What about others solutions. How would you position buttons for a calculator?
Kind regards and thanx angain!