Thread: My JPanel alignment is messy. How can I fix it?

Here is a ss of what I am talking about -



I want that particular JPanel to fill it's empty space.

I am using a layout manager to place 4 JPanels on a JFrame. However, I can't get the JPanel aligned WEST (with the JTextFields) to use up all of that empty space.

Here is what my constructor for that particular JPanel looks like:

	public UserParamsPanel() {
		params = UserParams.instance();
 
		pnlParams = new JPanel(new GridLayout(11, 2));
		//Define parameter labels.
		lblPreyLoneliness = new JLabel("Prey Loneliness");
		lblPreyEaten = new JLabel("Prey Eaten");
		lblPredatorIsolation = new JLabel("Predator Isolation");
		lblPredatorStarvation = new JLabel("Predator Starvation");
		lblPredatorLoneliness = new JLabel("Predator Loneliness");
		lblPreyReproduction = new JLabel("Prey Reproduction");
		lblPredatorReproduction = new JLabel("Predator Reproduction");
		lblPreySurvivalWhenPredators = new JLabel("Prey Survival when Predators");
		lblPredatorSurvivalWhenPrey = new JLabel("Predator Survival when Prey");
		lblPreyInitialProbability = new JLabel("Prey Initial Probability");
		lblPredatorInitialProbability = new JLabel("Predator Initial Probability");
 
		//Initialize text fields.
		txtPreyLoneliness = new JTextField(10);
		txtPreyEaten = new JTextField(10);
		txtPredatorIsolation = new JTextField(10);
		txtPredatorStarvation = new JTextField(10);
		txtPredatorLoneliness = new JTextField(10);
		txtPreyReproduction = new JTextField(10);
		txtPredatorReproduction = new JTextField(10);
		txtPreySurvivalWhenPredators = new JTextField(10);
		txtPredatorSurvivalWhenPrey = new JTextField(10);
		txtPreyInitialProbability = new JTextField(10);
		txtPredatorInitialProbability = new JTextField(10);
 
		//Add elements above to Panel.
		pnlParams.add(lblPreyLoneliness);
		pnlParams.add(txtPreyLoneliness);
		pnlParams.add(lblPreyEaten);
		pnlParams.add(txtPreyEaten);
		pnlParams.add(lblPredatorIsolation);
		pnlParams.add(txtPredatorIsolation);
		pnlParams.add(lblPredatorStarvation);
		pnlParams.add(txtPredatorStarvation);
		pnlParams.add(lblPredatorLoneliness);
		pnlParams.add(txtPredatorLoneliness);
		pnlParams.add(lblPreyReproduction);
		pnlParams.add(txtPreyReproduction);
		pnlParams.add(lblPredatorReproduction);
		pnlParams.add(txtPredatorReproduction);
		pnlParams.add(lblPreySurvivalWhenPredators);
		pnlParams.add(txtPreySurvivalWhenPredators);
		pnlParams.add(lblPredatorSurvivalWhenPrey);
		pnlParams.add(txtPredatorSurvivalWhenPrey);
		pnlParams.add(lblPreyInitialProbability);
		pnlParams.add(txtPreyInitialProbability);
		pnlParams.add(lblPredatorInitialProbability);
		pnlParams.add(txtPredatorInitialProbability);
 
		populateDefaultValues();
 
		add(pnlParams);
 
	}

It's really simple. You can see that I just create the fields in a grid layout, add them to the panel and add the panel to the class itself (which extends JPanel).

Is there a simple way I can modify my code so it will take up all of that empty space at the bottom of the panel? Any help is appreciated.

Thanks!!

Originally Posted by KevinWorkman

I'm confused by what exactly you're going for. Are you trying to change the size of the red outline? Are you trying to move the chart panel? Something else?

(btw, this program looks pretty interesting!)

Sorry, I should have been more specific.

Here is the example I am trying to mimic -



Notice how the JTextFields on the WEST are sized to where the content aligns perfectly with the graphic on the EAST side.

Basically, I want my JTextFields to take up all the usable space in the JPanel, without overlapping any of the other panels, so it can look just like the pic above.

I am using a layout manager BorderLayout to place the JPanels, but I still get that result. Just want some tips.


btw, the program is for a CS java programming class. It's one of those "evolution" simulators... seem to be popular projects among CS classes. I got it fully working, but my OCD has kicked in and I want the layout to be right too.

--- Update ---

Originally Posted by aussiemcgr

In the GridLayout class, there is the setVgap() method, which is supposed to set the vertical spacing between components. Try setting that and see what happens.

The issue isn't the gap, it's the width of the JTextFields. Though, I am wondering if there is an easier way to get the look I want w/o resizing all of the fields individually.

Though, I am wondering if there is an easier way to get the look I want w/o resizing all of the fields individually.

The easiest way *is* to manually resize. Divide the height of that exceptionally cool simulator by 11 (minus padding) and set the height of the JTextFields. You can add a ComponentListener to the JFrame and override the componentResized() method if you need dynamic resizing.

An alternative would be to use the GridBagLayout instead of the plain GridLayout. GridBagLayouts allow you to specify GridBagConstraints which gives the ability to define weighty = 1.0/11.0

As a foot note, I'd give this full marks if I were marking (so long as the code is as well thought out as this question and the stuff you've already posted). No program of worth is ever 100% complete and it's a mistake to go full OCD. As a professional you will have strict time constraints so get used to signing something off even though it isn't up to you're OCD needs.

No need to be respectful my friend - I learn more being wrong than right. BoxLayout makes a lot more sense than GridBags or a hard coding.

Thank you Kevin and Christopher. I might actually try both methods and see which gives the best results.

I already asked this question to my instructor, I know at this point I will get full marks anyway, but it's a matter of figuring out that last bit. I don't want to spend hours getting it right, which is why I wanted to find out a "quick" way. If I end up not easily figuring this out, I will just leave it as is, no harm no foul.

I need to put my attention toward the JUnit test cases for now. If I have enough time left before the project is due, I will try to get the alignment right.