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Change JTextField height on Swing

I'm trying to fix the height of the "amountField" text field, but I can't.
I would like the height of amountField to have the same height as the JComboBox that it's above, so it looks better.
Right now, the JTextField looks very tall compared with the rest of design.
I've tried everything that I've read in this forum, but nothing seems to work.
I don't know if it's relevant, but this whole JPanel (WithdrawalScreen) is inside another JPanel with BorderLayout. This panel is the center part of it
Thanks
PictureHere
public class WithdrawalScreen extends JPanel {
Public JPanel init() {
this.setLayout(new GridLayout(0,1));
account = new JLabel("account");
accountSelect = new JComboBox(labels);
amount = new JLabel("amount");
amountField = new JTextField("");
submit = new JButton("SUBMIT");
this.add(account);
this.add(accountSelect);
this.add(amount);
this.add(amountField);
this.add(submit);
return this;
}
}

Try creating the Grid Layout with 5 rows and 1 column. I think the height is messed up because you are not setting the constructor arguments properly.
new GridLayout(5,1);

Grid layout will stretch the component and give the same size to all of its components. In order to keep the "default" size of each component, you can use BoxLayout with BoxLayout.Y_AXIS parameter in its constructor. Another way would be to use a dummy-nested JPanel with another layout. Let's say FlowLayout.
JTextField textField = new JTextField(10);
JPanel nestedPanel = new JPanel(new FlowLayout());
nestedPanel.add(textField);
gridLayoutPanel.add(nestedPanel);
JTextField will not be stretched. nestedPanel will be. Do some experiments yourself and you will find the way that fits your needs.
A link that will help you: A visoual guide to Layout Managers.

Using a function to create multiple components and change line automatically [Java]

So i lost some hours already with this and i can't seem to find a solution.
Basically i have a Jframe and inside, i have a Scrollpane and a panel
I have 1 Jlabel, 1 JTextField and 1 JButton inside that panel in a single line.
The JButton can add a new JLabel, a new JTextField and a new JButton, but i can't get them to be positioned in the next line.
I have been messing around with the layouts, but none of them fits my needs, and unfortunaly i never understand or learned how the GUI of java Works.
How's the best way to just keep adding those componentes (Jlabel, Jtextfields and Jbuttons) on a next line for every click i made?
This is my code:
private void BtnaddvariableActionPerformed(java.awt.event.ActionEvent evt) {
JLabel Lblvariablextra = new JLabel("Testing");
PanelVariable.add(Lblvariablextra);
ScrollPaneVariable.setViewportView(PanelVariable);
}
The code only contains an exemple of the label tough.

Create a main panel that is added to the scroll pane when the GUI is created:
Box main = Box.createVerticalBox();
scrollPane.setViewportView( main );
Then in the ActionListener you create a child panel contain the 3 components every time the button is pressed:
JPanel child = new JPanel();
child.add( new JLabel("I'm a label") );
child.add( new JTextField(10) );
child.add( new JButton("Click Me") );
main.add(child);
Read the section from the Swing tutorial on Layout Manager to understand how layout management works.

Text goes outside JTextArea

I am trying to do something in Java which requires me to have a JTextArea in a ScrollPane.
Here is how I have defined them:
private JTextArea longestparagraph = new JTextArea();
....
JScrollPane scrollpanedreapta = new JScrollPane(longestparagraph,
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scrollpanedreapta.setBorder(BorderFactory.createTitledBorder("Cel mai lung paragraf:"));
The problem I'm encountering is that the text doesn't start on a new line when it reaches the right border of the TextArea but it continues. Got any ideas how to solve that? Here's a picture to make my statement a little bit clearer.

Found the answer. Just had to this:
longestparagraph.setLineWrap(true);
longestparagraph.setWrapStyleWord(true);

java jscrollpane

I have a problem with displaying the components of a JScrollPane. Let me first explain the context. I've got one big splitpane:
center = new JSplitPane(JSplitPane.VERTICAL_SPLIT, p, p1);
center.setDividerLocation(0.9);
center.setDividerSize(3);
center.setResizeWeight(1);
center.setContinuousLayout(true);
The p pane is shown the right way, no problem here. But the p1 pane won't be displayed, i can see the empty bottom-part of the splitPane, but that's all.
JPanel p = new JPanel();
p.add(canvas);
JPanel p1 = new JPanel();
p1.add(canvasPropPane);
The canvasPropPane is a scrollPane that i initialize like this:
VolumeSizeAndPosition volum = new VolumeSizeAndPosition();
canvasPropPane = new JScrollPane(volum);
volume was tested on an independent frame and have been shown the right way.
I tried showing on the canvasPropPane a simple button canvasPropPane.add(wildButton); and it has a strange behavior: it paints the button only after i hover the mouse over it's location; at repaint (after resizing the scrollpane) it disappears.

I've solved similar problems by calling invalidate() on all of the underlying nested Swing objects. So for your particular question p.invalidate() and p1.invalidate() may help. I believe this strange behavior to be a bug in Swing.

Please help me understanding BoxLayout alignment issues

I'm trying to create a very simple window using Java Layouts. I have got three elements to arrange: a button, a progress bar and a label. The button has to be vertically centered, the progress bar has to take full width, and the label has to be left aligned.
Here's some code (just assume pane is the content pane of a JFrame, and button, progressBar and label have been created before):
BoxLayout layout = new BoxLayout(pane, BoxLayout.Y_AXIS);
pane.setLayout(layout);
button.setAlignmentX(Component.CENTER_ALIGNMENT);
pane.add(button);
progressBar.setAlignmentX(Component.CENTER_ALIGNMENT);
pane.add(progressBar);
label.setAlignmentX(Component.LEFT_ALIGNMENT);
pane.add(label);
When I test the application I see everything misaligned and screwed up: the button and the label are randomly indented, and if I resize the window the indentation amount changes in a strange way.
The progress bar looks good (full width).
I just don't understand what's happening. Can you give me a clue?

BoxLayout cannot handle different alignments: see http://download.oracle.com/javase/tutorial/uiswing/layout/box.html
quoting from that article: "In general, all the components controlled by a top-to-bottom BoxLayout object should have the same X alignment. Similarly, all the components controlled by a left-to-right Boxlayout should generally have the same Y alignment."

Sometimes you need to get a little creative and use nested panels. But I like this approach better then trying to learn and memorize all the constraints required when using other layout managers (GridBagLayout, GroupLayout) there where designed to be used by IDE's that generate code for you.
import java.awt.*;
import javax.swing.*;
public class BoxLayoutVertical extends JFrame
{
public BoxLayoutVertical()
{
Box box = Box.createVerticalBox();
JButton button = new JButton("A button");
button.setAlignmentX(Component.CENTER_ALIGNMENT);
box.add(button);
JProgressBar progressBar = new JProgressBar(0, 100);
progressBar.setAlignmentX(Component.CENTER_ALIGNMENT);
box.add(progressBar);
JPanel panel = new JPanel( new BorderLayout() );
JLabel label = new JLabel("A label");
label.setAlignmentX(Component.LEFT_ALIGNMENT);
panel.add(label);
box.add(panel);
add(box, BorderLayout.NORTH);
}
public static void main(String[] args)
{
BoxLayoutVertical frame = new BoxLayoutVertical();
frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
frame.setSize(300, 200);
frame.setLocationRelativeTo( null );
frame.setVisible(true);
}
}

To complement my comment to the original question, here is a snippet that uses DesignGridLayout:
JButton button = new JButton("Button");
JProgressBar progressBar = new JProgressBar();
JLabel label = new JLabel("Label");
// The interesting stuff is in the next 4 lines
DesignGridLayout layout = new DesignGridLayout(getContentPane());
layout.row().center().add(button).withOwnRowWidth();
layout.row().center().fill().add(progressBar);
layout.row().left().add(label);
pack();
It does exactly what wou describe in your question and doesn't require any specific call of any of the components.

Maybe your code is just a snippet, but I'm missing a call to pack().
Coding swing layout by hand can be very frustrating with the standard Layout managers. I use MiG Layout for that purpose. It is straight forward and you have a nice layout with just a few lines of code. If you're not forced to use BoxLayout I would suggest you give it a try.

Don't use BoxLayout. It works only for very simple cases.
For your case, I would recommend either GridBagLayout or (my favorite) GroupLayout.
For GroupLayout, I created a subclass (LayoutHelper) with some utility methods and useful constructors, which makes writing the Layout much easier.
Of course, usually I align all components in a group the same way, so it is not as short in your case as it would be in the simple case.
LayoutHelper h = new LayoutHelper(pane);
h.setVerticalGroup
( h.sequential( button, progressBar, label));
h.setHorizontalGroup
( ((ParallelGroup)h.parallel())
.addComponent(button, Alignment.CENTER)
.addComponent(progressBar)
.addComponent(label, Alignment.TRAILING));
Here is a screenshot:
For a simple "everything aligned the same way", the horizontal group would look like this:
h.setHorizontalGroup
( h.parallel (button, progressBar, label));
(optionally with a first argument indicating the alignment).