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Can't left align a JLabel within a JPanel when adding to a BorderLayout

This seems like a simple thing to do, but I can't get it to work.
I have a BorderLayout. I want to use the top part for a title bar. I want to add a JPanel with labels, buttons and other components. However, the PAGE_START part of the border layout won't left align the panel. Here's the situation, with comments in where I've tried to set the alignment.
I noticed that when I don't add a panel to the border layout, and just write the JLabel straight in, it has left alignment by default.
This is not what I want, though, because I am planning on putting a BoxLayout.X_AXIS horizontally through the BorderLayout.PAGE_START title area. Seems to be a reasonable thing to do?
The Container pane argument to the static method is just the single panel on the main JFrame.
public static void addComponentsToPane(Container pane)
{
JLabel jlabel = new JLabel("I want to left align this inside a JPanel");
// Doesn't work: jlabel.setAlignmentX(Component.LEFT_ALIGNMENT);
JPanel jpanel = new JPanel();
//Doesn't work: jlabel.setAlignmentX(Component.LEFT_ALIGNMENT);
jpanel.add(jlabel);
pane.add(jpanel, BorderLayout.PAGE_START);
// Other parts of the BoxLayout (works fine)
JButton button = new JButton("Button 2 (CENTER)");
button.setPreferredSize(new Dimension(200, 100));
pane.add(button, BorderLayout.CENTER);
button = new JButton("Button 3 (LINE_START)");
pane.add(button, BorderLayout.LINE_START);
button = new JButton("Long-Named Button 4 (PAGE_END)");
pane.add(button, BorderLayout.PAGE_END);
button = new JButton("5 (LINE_END)");
pane.add(button, BorderLayout.LINE_END);
}
Even when I tell the panel to left align the label, it doesn't appear left aligned.
Does anyone know what I am doing wrong?

By default a JPanel uses a FlowLayout with "center" alignment.
if you want components "left" aligned, then you need to set the layout on the panel to use a FlowLayout with "left" alignment.
Read the FlowLayout API for the proper constructor to use to set the alignment.
Or you can also read the Swing tutorial on How to Use FlowLayut which gives the constructors and valid values to specify the alignment.

Adding JButtons in for loop

JAVA Swing Problem
I want to create a list of JButtons based on a list of strings, which represents the button text.
In my first step, I collect my data for the button texts from an external text file. This data is stored in the data variable.
List<String> data = ReadFile("texts.txt")
Now I want to create the list of JButtons, named buttons. There I set their text and their Bounds. The Bounds are relative to the index, so the buttons are placed below each other. Finally, I add the button to the frame and to the buttons list.
List<JButton> buttons = new ArrayList<>();
for (int index = 0; index < data.size(); index++) {
JButton button = new JButton();
button.setText(data.get(index));
button.setBounds(0, index*50, 100, 50);
add(button);
buttons.add(button);
But when I execute this, the last Button ends big, the first ones also disappear when I don't hover over them, but that's based on the fact, that the last button ist placed above:
Picture of the executed script
The last button has the size of the frame, doesn't matter, if I resize the frame:
Picture of the resized screen
I hope someone can help me or tell me where I can find help. Thanks.

the last Button ends big, the first ones also disappear when I don't hover over them,
That is because by default the content pane of the JFrame uses a BorderLayout. When you add a component to the BorderLayout the button is added to the CENTER. However, only a single component can be added to the CENTER, so only the size/location of the last component added is managed by the BorderLayout.
Don't attempt to set the size/location of your components manually. It is the job of a layout manager to do this. In your case you can use a couple of panels with different layout so align your button in a column on the left. Something like:
JPanel buttonPanel = new JPanel( new GridLayout(0, 1) );
for (int index = 0; index < data.size(); index++) {
JButton button = new JButton();
button.setText(data.get(index));
button.setBounds(0, index*50, 100, 50);
//add(button);
buttonPanel.add( button );
buttons.add(button);
}
add(buttonPanel, BorderLayout.LINE_START);
Try the above code and you will notice that the buttons are all the same size, but the size keeps changing as the height of the frame changes.
So to prevent this resizing we need to allow the button to be displayed at their preferred height by using an additional layout manager:
//add(buttonPanel, BorderLayout.LINE_START);
JPanel wrapper = new JPanel( new BorderLayout() );
wrapper.add(buttonPanel, BorderLayout.PAGE_START);
add(wrapper, BorderLayout.LINE_START);
Read the Swing tutorial on Layout Manager for more information and examples.

Grid layout not working?

I am trying to make a 2x2 grid layout that has a JLabel on the top left, and three buttons on the other three spaces. When I do this, I get the unexpected result of one big button (filling up the entire JDialog) that says "Do you want to push me". I don't know why this result shows up, please help, Thanks!
public void sinceyoupressedthecoolbutton() {
JDialog replacementwindow = new JDialog(); //Like a window
JButton best = new JButton("best");
JButton first = new JButton("FIRST");
JButton second = new JButton("Second");
replacementwindow.setLayout(new GridLayout(2,3,0,0)); //Row, column, distance horizontally, distance vertical
JPanel panel = new JPanel();
replacementwindow.add(panel); //adding the JPanel itself
replacementwindow.add(first);
replacementwindow.add(second);
replacementwindow.add(best);
replacementwindow.setSize(500, 500);
replacementwindow.setTitle("NEW WINDOW!");
replacementwindow.setVisible(true);
}

It's because you set the layout of your JButton, and not of your JDialog
Change
label.setLayout(new GridLayout(2,2,0,0));
to
YES.setLayout(new GridLayout(2,2,0,0));
Also, your variable called label is a JButton, you probably want to change that.

Don't add components to a button. You add components to a panel.
So the basic code should be:
JDialog dialog = new JDialog(...);
JPanel panel = new JPanel( new GridLayout(...) );
panel.add(label);
panel.add(button1);
...
dialog.add(panel);
Also, variable names should NOT start with an upper case character! "Yes" does not follow Java standards. The other variables do. Be consistent!

JTextField becomes HUGE in a HorizontalBox

Please consider this Java code fragment:
Box buttonBox = Box.createHorizontalBox();
buttonBox.add(new JCheckBox("Select all"));
buttonBox.add(Box.createHorizontalGlue());
buttonBox.add(new JLabel("Filter: "));
buttonBox.add(new JTextField());
Box paneBox = Box.createVerticalBox();
paneBox.add(buttonBox);
paneBox.add(new JScrollPane(jList));
For some reason i don't get, the JTextField takes up most of the screen. The jList isn't even visible anymore. I would like to know why and how to fix it.
When i comment the line with the JTextField, it looks fine (except no JTextField, of course). Why does the JCheckBox and the JLabel not get ridiculously big? What is the purpose of a one-line JTextField being able to take up almost the whole screen?
Most people suggest to set the size of the JTextField field to my needs. However, i read that i should not call these methods, but let the LayoutManager take care of it. Now what is the most elegant solution to prevent the JTextField from becoming so big?

Try using the setPreferredSize method like this:
textFieldName.setPreferredSize(new Dimension(x, y));
Obviously input the values for x and y that you wish the JTextField size to be

You can avoid this problem by using a simple JPanel() instead of a Box for the horinzontal one. And after just set the prefered size to your JTextField.
//Box buttonBox = Box.createHorizontalBox();
JPanel buttonBox = new JPanel();
buttonBox.add(new JCheckBox("Select all"));
buttonBox.add(Box.createHorizontalGlue());
buttonBox.add(new JLabel("Filter: "));
JTextField jt = new JTextField();
jt.setPreferredSize(new Dimension(100,25));
buttonBox.add(jt);
EDIT
Btw the defaut Layout of a JPanel is the FlowLayout which place components from left to right and with centered alignement by default. You can still change the alignement.
For example:
JPanel buttonBox = new JPanel(new FlowLayout(FlowLayout.LEFT));
You can also change the gap between each components. There is some other Layout like the BorderLayout or GridLayout / GridBagLayout. I let you search on Google for more information about them.
See in yellow the JPanel, in red the VerticalBox

Box box = Box.CreateVerticalBox();
Use box.setMaximumSize(Dimension(160,80))
and box.setMinimumSize(Dimension(160,80))
then it will work :D
If you need a strut for your layout, put it in between boxes.

Change the way JRadioButtons displayed on JPanel [duplicate]

This question already has an answer here:
How can I use BoxLayout to do this?
(1 answer)
Closed 9 years ago.
I have a JPanel, and I want to add JRadioButtons to it, this is the code I tried :
private void populateQuestionnaire(Question question){
buttonGroup = new ButtonGroup();
for(Choix c : question.getListChoix()) {
radioButton = new JRadioButton(c.getChoixLibelle());
buttonGroup.add(radioButton);
jPanel1.add(radioButton);
}
jPanel1.revalidate();
jPanel1.repaint();
}
And I have the layout of JPanel is FlowLayout.
This is how the JRadioButtons displayed :
I want JRadioButtons to be added one below the other and to be centered in the JPanel.

Instead of using a FlowLayout, which lays out items left to right and wraps appropriately, you can use a BoxLayout, which allows you to specify laying out items either horizontally or vertically.
You can set the LayoutManager for your JPanel at construction:
JPanel jpanel1 = new JPanel(new BoxLayout(parentComponent, BoxLayout.Y_AXIS));

BoxLayout is great for stacking elements on top of each other. Consider this code:
public class MyFrame extends JFrame {
public MyFrame() {
ButtonGroup bg = new ButtonGroup();
JRadioButton b1 = new JRadioButton("My Button 1");
JRadioButton b2 = new JRadioButton("My Button 2");
bg.add(b1);
bg.add(b2);
BoxLayout bl = new BoxLayout(this.getContentPane(), BoxLayout.Y_AXIS);
this.setLayout(bl);
b1.setAlignmentX(CENTER_ALIGNMENT);
b2.setAlignmentX(CENTER_ALIGNMENT);
this.add(b1);
this.add(b2);
}
}
Which makes, when instantiated and shown, the following window:
Now let's look at how this code works:
Consider this code:
ButtonGroup bg = new ButtonGroup();
JRadioButton b1 = new JRadioButton("My Button 1");
JRadioButton b2 = new JRadioButton("My Button 2");
bg.add(b1);
bg.add(b2);
This code does the same thing you were doing before, only a little simpler for example's sake. It creates a button group and two JRadioButtons, then adds the buttons to the button group. Now here is when it gets interesting.
Next, consider this code:
BoxLayout bl = new BoxLayout(this.getContentPane(), BoxLayout.Y_AXIS);
this.setLayout(bl);
The first line creates a new BoxLayout with the following parameters:
1 The container which it is laying out. (It needs this because it can't be shared.)
2 The axis which it should be laying out components. (You want Y-AXIS for your case.)
The second line set's the JFrame's contentPane's layout to the BoxLayout you just created.
Finally, consider this code:
b1.setAlignmentX(CENTER_ALIGNMENT);
b2.setAlignmentX(CENTER_ALIGNMENT);
this.add(b1);
this.add(b2);
This sets the alignment of the two radio buttons so that their centers will be aligned to each other and to the center of the frame. Then it adds them to the frame's content pane.
Hope this helped!
Note: The reason I used this.getContentPane() while constructing the BoxLayout instead of just using this is because when working with JFrames commands like add() and setLayout() get redirected to the frame's content pane. So if we were to use this in the constructor, when we called this.setLayout(bl) we really would be calling this.getContentPane().setLayout(bl). But, we just told the BoxLayout it'll be laying out the frame, not it's content pane, so you'll get an exception saying that the BoxLayout can't be shared. To correct the error, we just need to realise that we are actually working with the content pane through the frame's methods, and update the BoxLayout's constructor accordingly to let it know what it really is laying out.