I am developing a simple application, and am currently working on the gui design using Swing. In my program I have a JPanel which I would like to have a background color black like so:
JPanel playerPanel = new JPanel();
playerPanel.setOpaque(true);
playerPanel.setBackground(Color.BLACK);
This code works fine. However, the problem is when I assign a Layout Manager to the panel:
JPanel playerPanel = new JPanel();
playerPanel.setOpaque(true);
playerPanel.setBackground(Color.BLACK);
playerPanel.setLayout(new BoxLayout(playerPanel, BoxLayout.PAGE_AXIS));
For some reason, this makes the black color of the panel go away. This happens no matter where I place the .setLayout(...) command, before or after the .setBackground(...) and .setOpaque(true).
Why is this, and how do I work around this? How do I keep a black JPanel that uses a BoxLayout manager?
Verify that your panel's content is not obscuring the altered background. Resize the example below, which I've artificially enlarged, to see the effect.
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.util.Random;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
/**
* #see https://stackoverflow.com/a/57785802/230513
*/
public class BoxTest {
public static final Random random = new Random();
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
new BoxTest().create();
}
});
}
void create() {
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
panel.setBackground(Color.BLACK);
panel.add(Box.createVerticalGlue());
for (int i = 0; i < 4; i++) {
panel.add(new VariablePanel());
panel.add(Box.createVerticalGlue());
}
JFrame f = new JFrame("BoxTest");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(panel);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
f.setSize(f.getWidth(), f.getHeight() + 64);
}
}
/**
* A VariablePanel has a label showing its current size,
* as well as a variable number of text items.
*/
class VariablePanel extends JPanel {
private static final String text =
"Sed ut perspiciatis unde omnis iste natus error sit.";
private final JLabel sizeLabel = new JLabel("Size:");
public VariablePanel() {
this.setLayout(new GridLayout(0, 1));
this.add(sizeLabel);
int count = BoxTest.random.nextInt(5) + 1;
for (int i = 0; i < count; i++) {
this.add(new JLabel(text));
}
this.addComponentListener(new ComponentAdapter() {
#Override
public void componentResized(ComponentEvent e) {
int w = e.getComponent().getWidth();
int h = e.getComponent().getHeight();
sizeLabel.setText("Size: " + w + "\u00d7" + h);
}
});
}
}
Swing components (except JLabel) are opaque by default. This means:
you don't need playerPanel.setOpaque(true)
most components you add to the panel will be opaque and cover the background of your playerPanel.
Also, the BoxLayout respects the maximum size of any component you add to the panel. So if you add a component:
like a JButton which has a defined maximum size, you will see the button on top of the playerPanel and the background will surround the button.
like a JPanel, which does not have a defined maximum size, the panel will be resized to fill the entire area of the playerPanel and you won't see the background of the playerPanel.
If you want to see the background of the playerPanel show through a component added to the playerPanel, then you need to use setOpaque(false) on the component. For example:
JPanel child = new JPanel();
child.setOpaque( false );
playerPanel.add( child );
Related
I'm programming a cookie clicker game remake and when I scale the JFrame window, something white appears. It disappears as soon as you hover the cursor over the button(when refreshes) and I need to fix that, because it does even the same when you launch the game.
Here's a screenshot(UNSCALED | SCALED): http://s3.postimg.org/xomifomhf/bandicam_19.png
this is the whole code of this game:
package cookieclicker.tominocz;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import javax.swing.BorderFactory;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Main {
public static int num1;
static Icon icon1 = new ImageIcon("cookie.png");
static JButton b1 = new JButton(icon1);
static JButton b2 = new JButton("You got " + num1 + " Cookies!");
#SuppressWarnings("serial")
public static void main(String[] args) {
File save = new File(".\\gamesave.cookieclicker");
if (save.exists()) {
loadGame();
}
JFrame f = new JFrame("Cookie Clicker Beta v0.1");
b2.setBackground(Color.cyan);
b2.setPreferredSize(new Dimension(10000, 14));
JPanel buttonPanel1 = new JPanel(new GridLayout(1, 1));
buttonPanel1.setBackground(Color.DARK_GRAY);
b2.setEnabled(false);
b2.setBorder(null);
buttonPanel1.add(b2);
JPanel buttonPanel2 = new JPanel(new GridLayout(1000, 1));
buttonPanel2.setBackground(Color.DARK_GRAY);
buttonPanel2.setEnabled(false);
buttonPanel2.add(new JButton("Grandma"));
buttonPanel2.add(new JButton(""));
buttonPanel2.add(new JButton(""));
JPanel east = new JPanel(new GridBagLayout());
JPanel north = new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.anchor = GridBagConstraints.NORTH;
gbc.weighty = 1;
north.add(buttonPanel1, gbc);
east.add(buttonPanel2, gbc);
JPanel center = new JPanel() {
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
};
center.setBorder(BorderFactory.createLineBorder(Color.BLACK));
f.add(east, BorderLayout.EAST);
f.add(north, BorderLayout.NORTH);
f.add(center);
f.pack();
f.setSize(600, 400);
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
b1.setBackground(Color.lightGray);
b1.setBorder(null);
f.add(b1);
b1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
if (source instanceof JButton) {
addCookies();
}
}
});
}
public static void addCookies() {
saveGame();
b2.setText("You got " + ++num1 + " Cookies!");
if (num1 == 1) {
b2.setText(" You got " + 1 + " Cookie! ");
} else {
b2.setText("You got " + num1 + " Cookies!");
}
System.out.println(num1);
}
public static void saveGame() {
try {
BufferedWriter writer = new BufferedWriter(new FileWriter(
".\\gamesave.cookieclicker"));
writer.write(String.valueOf(1 + num1));
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public static void loadGame() {
try (BufferedReader br = new BufferedReader(new FileReader(
".\\gamesave.cookieclicker"))) {
String SavedGame;
while ((SavedGame = br.readLine()) != null) {
num1 = Integer.parseInt(SavedGame);
b2.setText("You got " + num1 + " Cookies!");
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
And also the other thing is, that the dark grey strip is hiding 3 buttons.
Don't count the 4th one, that's the one showing the ammount of cookies you have :).
Now where could the problem be?
You have two components sharing the CENTRE position of the frame's BorderLayout, center and b1.
b1, been the last component added, is getting the attention of the layout manager and is been laid out when the frame is resized, center is not and is remaining at the last size/position it was set to (because you called pack, which forced the frame to layout it's child components, but then you added b1 after it).
BorderLayout can only manage a single component at each of it's five pre-defined positions
Make a decision about who should be in the centre...
You should also have a read of Should I avoid the use of set(Preferred|Maximum|Minimum)Size methods in Java Swing? and stop messing with the preferred size of your components, let them make their own decisions in combination with appropriate layout managers
I'd also encourage you to move the content of your main method some where else (may be the class's constructor), this way, you fields won't need to be static and it solve a ton of other issues you might have in the future
First of all:
b2.setPreferredSize(new Dimension(10000, 14));
Don't specify preferred sizes for components. Each component is responsible for determining its own preferred size. Let the layout manager determine the size.
JPanel buttonPanel2 = new JPanel(new GridLayout(1000, 1));
Don't use random numbers when defining the GridLayout. If you want one column then just use: new GridLayout(0, 1). Now all components added will be displayed in the first row.
Now for your problem:
f.add(center);
f.pack();
You add an empty panel to the CENTER of the BorderLayout. Then you pack the frame so the panel now has a valid size.
f.add(b1);
But then you add a second component to the "CENTER". However BorderLayout will only manage the size of the last component added.
Swing will paint() the last component added first, so the button is painted, then the panel is painted over top of it.
If you move the mouse over the center, then the mouse event is passed to the button and the rollover logic is invoked so the button is painted.
If you resize the frame, the buttons size is recalculated by the layout manager and components are repainted. Again, the center panel is painted last so you see part of the button with the panel on top.
I don't know why you have the center panel so I can't make a specific suggestion other than to say, get rid of it. Again the main problem is you are trying to add two components to the center. Don't do this!
I'm trying to resize a label on MouseEnter, but on MouseExit, I want it back to the previous state. How would I do this?
I want the label to be bigger when it is moused over, but when the mouse exits, the label will back to normal size.
Can anybody explain to me how to do that?
If it's possible, I want to see the resize slowly.
This is the code:
package kk
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridLayout;
import javax.swing.GroupLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
public class ScrollGroup extends JPanel {
private static final int N = 8;
private static final int NN = N * N;
private static final int GAP = 5;
private static final int SIZE = 100;
public ScrollGroup() {
this.setLayout(new GridLayout(N, N, GAP, GAP));
for (int i = 0; i < NN; i++) {
final JLabel label = new JLabel();
label.setOpaque(true);
label.setBackground(Color.getHSBColor((float) i / NN, 1, 1));
label.setPreferredSize(new Dimension(SIZE, SIZE));
this.add(label);
label.addMouseListener(new MouseAdapter() {
public void mouseEntered(MouseEvent e){
}
public void mouseExited(MouseEvent e) {
}
});
}
}
private void display() {
JFrame f = new JFrame("ScrollGroup");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JScrollPane sp = new JScrollPane(this);
GroupLayout layout = new GroupLayout(f.getContentPane());
f.setLayout(layout);
layout.setAutoCreateGaps(true);
layout.setAutoCreateContainerGaps(true);
layout.setHorizontalGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup().addComponent(sp)));
layout.setVerticalGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup().addComponent(sp)));
f.pack();
f.setSize(N * SIZE, N * SIZE);
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new ScrollGroup().display();
}
});
}
}
I'm trying to resize a label in MouseEntred,
Define "resize".
You are adding your JLabels to a panel using a GridLayout. All the labels are already set to the maximum size permitted by the space available to the panel, so what do you expect the resize to do?
If you want it to appear that the label is getting bigger, then maybe you can assign a MatteBorder to each label. You can make the MatteBorder whatever size you want and then set the color equal to the background color of the panel.
If you want to animate then then you can use a Swing Timer. In the mouse#ntered you start the Timer. Every time the Timer fires you change the MatteBorder to be one less pixedl until the size is zero and you stop the Timer. On mouseExited, you just restore the default Border.
See the sections from the Swing tutorial on How to Use Timers and How to Use Borders for more information.
I have a JTabbed pane, which has a varying number of tabs. When the number of tabs is greater than 4, I get extra spacing/padding at the bottom of each tab panel. The picture below shows this (on the left you see the extra spacing, on the right you see no extra spacing).
Here is the exact code I used to get those pictures:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import javax.swing.JDialog;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;
public class DialogTest {
public static void main(String[] args) {
new DialogTest();
}
public DialogTest() {
JDialog dialog = new MyDialog();
dialog.pack();
dialog.setVisible(true);
}
class MyDialog extends JDialog {
public MyDialog() {
super(null, ModalityType.APPLICATION_MODAL);
final JTabbedPane tabs = new JTabbedPane();
final int numTabs = Integer.parseInt(JOptionPane.showInputDialog("Number of tabs:"));
setPreferredSize(new Dimension(400, 200));
for (int i = 1; i <= numTabs; i++) {
tabs.addTab("Tab"+i, new MyPanel(i));
}
setLayout(new BorderLayout());
add(tabs, BorderLayout.NORTH);
}
}
class MyPanel extends JPanel {
public MyPanel(int text) {
final JLabel label = new JLabel("THIS IS A PANEL" + text);
label.setFont(label.getFont().deriveFont(18f));
label.setBackground(Color.cyan);
label.setOpaque(true);
add(label);
setBackground(Color.red);
}
}
}
I've tried numerous things including many different layout managers. I can't for the life of me get rid of that extra spacing. Any help would be great.
final JTabbedPane tabs = new JTabbedPane();
tabs.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT); // ADD THIS!
The reason the other example behaves as it does is that the pane wraps the tabs to the next line & presumes that once we have gone beyond as many tabs as it might naturally display in a single line, it must increase the preferred size to include that extra line of tabs.
Can anyone help me? Whenever I ran the codes below, it always returns a blank frame, I don't know where I did wrong. Can you guys help me debug this? I already added the components to the panel, and the panel to the frame, but still it returns a blank output.
Here is the output I'm getting:
While this is what is required.
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.JButton;
import javax.swing.ButtonGroup;
import javax.swing.BorderFactory;
import javax.swing.UIManager;
import javax.swing.BoxLayout;
import java.awt.GridLayout;
import java.awt.EventQueue;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.BorderLayout;
import java.awt.Color;
import javax.swing.JRadioButton;
/**
*
* #author Chareux
*/
//Declaring Variables
public class TestUI {
private JFrame frm_main;
private JPanel sr_pnl;
private JLabel sr_lbl;
private JLabel sr_lbl2;
private JLabel ret_optn_lbl;
private JLabel ret_rsn_lbl;
private ButtonGroup ret_ops;
private JTextField sr_txtnum;
private JTextField sr_ret_txtrsn;
private JButton sr_start;
private JRadioButton ret_optn_rdbn_y;
private JRadioButton ret_optn_rdbn_n;
public TestUI(){
start();
}
public void start(){
//Creating the JFrame
frm_main = new JFrame("Service Desk SR Tool");
frm_main.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frm_main.setSize(500,450);
frm_main.setLocationRelativeTo(null);
frm_main.setResizable(false);
frm_main.setVisible(true);
// the Panel
sr_pnl = new JPanel();
//Components
sr_lbl = new JLabel("SERVICE DESK SR TIMER!");
sr_lbl2 = new JLabel("SR number: ");
sr_txtnum = new JTextField("Enter SR number here..",20);
ret_optn_lbl = new JLabel("Returning Ticket?");
ret_optn_rdbn_y = new JRadioButton("Yes");
ret_optn_rdbn_n = new JRadioButton("No");
ret_rsn_lbl = new JLabel("Reason: ");
sr_ret_txtrsn = new JTextField("Enter Reason number here..",20);
sr_start = new JButton("START!");
//adding the Components to the panel
sr_pnl.add(sr_lbl);
sr_pnl.add(sr_lbl2);
sr_pnl.add(sr_txtnum);
sr_pnl.add(ret_optn_lbl);
sr_pnl.add(ret_optn_rdbn_y);
sr_pnl.add(ret_optn_rdbn_n);
sr_pnl.add(ret_rsn_lbl);
sr_pnl.add(sr_ret_txtrsn);
sr_pnl.add(sr_start);
frm_main.add(sr_pnl,BorderLayout.CENTER);
//ButtonGroup for the radio button
ret_ops = new ButtonGroup();
ret_ops.add(ret_optn_rdbn_y);
ret_ops.add(ret_optn_rdbn_n);
}
public static void main(String[] args) {
new TestUI();
}
}
I'd recommend to use a nested or compound layout for this task. See further tips in comments in the source.
import java.awt.*;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
public class SRTool {
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
// the GUI as seen by the user (without frame)
JPanel gui = new JPanel(new GridLayout(0,1,6,6));
gui.setBorder(new EmptyBorder(2, 3, 2, 3));
// show the BG
gui.setBackground(Color.CYAN);
// center the label text
gui.add(new JLabel(
"Service Desk SR Tool", SwingConstants.CENTER));
// create a lyout that can center multiple components
FlowLayout layout = new FlowLayout(FlowLayout.CENTER,5,5);
JPanel srPanel = new JPanel(layout);
gui.add(srPanel);
srPanel.add(new JLabel("SR:"));
srPanel.add(new JTextField(8));
JPanel returnTicketPanel = new JPanel(layout);
gui.add(returnTicketPanel);
returnTicketPanel.add(new JLabel("Returning Ticket?"));
returnTicketPanel.add(new JCheckBox());
JPanel reasonPanel = new JPanel(layout);
gui.add(reasonPanel);
reasonPanel.add(new JLabel("Reason:"));
reasonPanel.add(new JTextField(14));
JPanel buttonPanel = new JPanel(layout);
gui.add(buttonPanel);
buttonPanel.add(new JButton("Start!"));
JFrame f = new JFrame("Demo");
f.add(gui);
// Ensures JVM closes after frame(s) closed and
// all non-daemon threads are finished
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
// See https://stackoverflow.com/a/7143398/418556 for demo.
f.setLocationByPlatform(true);
// ensures the frame is the minimum size it needs to be
// in order display the components within it
f.pack();
// should be done last, to avoid flickering, moving,
// resizing artifacts.
f.setVisible(true);
}
};
// Swing GUIs should be created and updated on the EDT
// http://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html
SwingUtilities.invokeLater(r);
}
}
Java GUIs might have to work on a number of platforms, on different screen resolutions & using different PLAFs. As such they are not conducive to exact placement of components. To organize the components for a robust GUI, instead use layout managers, or combinations of them1, along with layout padding & borders for white space2.
Add frm_main.validate() in the end of start()
public void start(){
/*
...
Same As Above
...
*/
frm_main.add(sr_pnl,BorderLayout.CENTER);
//ButtonGroup for the radio button
ret_ops = new ButtonGroup();
ret_ops.add(ret_optn_rdbn_y);
ret_ops.add(ret_optn_rdbn_n);
frm_main.validate(); // Add this line ******
}
So I have a class called CalendarPanel that extends JPanel. It uses a null layout. How would I use CalendarPanel as a regular component? When I put it in another JPanel and then add it to a window, it disappears. It is only visible when I add it directly to a window.
EDIT:
And yes, I realize using a JPanel with a null layout is bad practice. CalendarPanel is actually someone else's code, and I'm trying to use it for my purposes without having to refactor it.
It is only visible when I add it directly to a window.
That is because a window uses a BorderLayout by default and will automatically resize the panel to fit in the window.
When I put it in another JPanel and then add it to a window, it disappears.
The is because a JPanel uses a FlowLayout by default and a flow layout respects the preferred size of the components added to it. Since you are using a null layout your panel doesn't have a preferred size so nothing gets painted.
That is why you should NOT use null layout. Instead use layout managers because they do all this extra work for you.
NOTE: it is a very bad idea in general to use a null layout. Use a LayoutManager instead.
If you insist on using a null layout, you're going to have to position the JPanel manually as mentioned in the documentation. Here's an example.
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class Test extends JFrame {
static int defaultX = 10;
static int defaultY = 10;
static int defaultW = 150;
static int defaultH = 50;
public Test() {
super("Test");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// here is the outer JPanel
final JPanel outer = new JPanel(new BorderLayout());
JPanel inner = new JPanel(new BorderLayout());
// here is the main component we want to see
// when the outer panel is added to the null layout
JButton mainComponent = new JButton("Test");
inner.add("Center", mainComponent);
outer.add("Center", inner);
JPanel c = (JPanel)getContentPane();
// This panel has a null layout!
final JPanel nullLayoutPanel = new JPanel();
nullLayoutPanel.setLayout(null);
c.add("Center", nullLayoutPanel);
// set the bounds of the outer panel manually
// when using the null layout!
nullLayoutPanel.add(outer);
outer.setBounds(defaultX, defaultY, defaultW, defaultH);
JPanel controlPanel = new JPanel(new FlowLayout(FlowLayout.CENTER, 10, 10));
final JTextField x = new JTextField(""+defaultX, 3);
final JTextField y = new JTextField(""+defaultY, 3);
final JTextField w = new JTextField(""+defaultW, 3);
final JTextField h = new JTextField(""+defaultH, 3);
JButton b = new JButton("Resize");
b.addActionListener(
new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
outer.setBounds(
Integer.parseInt(x.getText()),
Integer.parseInt(y.getText()),
Integer.parseInt(w.getText()),
Integer.parseInt(h.getText())
);
outer.revalidate();
} catch(Exception ex) {}
}
}
);
controlPanel.add(x);
controlPanel.add(y);
controlPanel.add(w);
controlPanel.add(h);
controlPanel.add(b);
c.add("South", controlPanel);
}
public static void main(String[] argv) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
Test p = new Test();
p.setSize(300, 200);
p.setVisible(true);
}
});
}
}