A rather minimal example: This lays out a JLabel in a JPanel, stuffs the JPanel into a JScrollPane, and sticks that in a JFrame. I then want the pane to scroll so as to make the JLabel visible, but it does not do so. I've tried calling scrollRectToVisible on the label and the panel, with no luck, messed around with viewports, with no luck, tried setting scrollbar values manually, with no luck. Clearly I'm doing something stupid, but I can't see what.
import java.awt.Dimension;
import java.awt.Rectangle;
import javax.swing.*;
public class SillyTest {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JPanel panel = new JPanel();
GroupLayout layout = new GroupLayout(panel);
panel.setLayout(layout);
GroupLayout.SequentialGroup seq = layout
.createSequentialGroup();
GroupLayout.ParallelGroup par = layout.createParallelGroup();
JLabel fish = new JLabel("fish");
seq.addGap(3000);
seq.addComponent(fish);
par.addComponent(fish);
par.addGap(200);
layout.setHorizontalGroup(par);
layout.setVerticalGroup(seq);
JScrollPane scrollPane = new JScrollPane(panel);
JFrame frame = new JFrame("whatever this is about");
frame.add(scrollPane);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
fish.scrollRectToVisible(fish.getBounds());
}
});
}
}
Code works fine for me using JDK7 on Windows7.
If you have an issue on a different version then you can try:
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
fish.scrollRectToVisible(fish.getBounds());
}
});
This just makes sure the scrollRectToVisible() is added to the end of the EDT so it should be processed after all the initial logic to display the frame has occurred.
Related
This is the add(main) version
This is the add(scroll) version
Im trying to get a window full of lables and make it scrollable, this is my code for that purpose:
public class JobHistoryListScreen extends JFrame implements View
{
#Override
public void showScreen()
{
setSize(800, 800);
setLayout(new BorderLayout());
setDefaultCloseOperation(EXIT_ON_CLOSE);
JPanel main = new JPanel();
main.setSize(500,500);
JScrollPane scroll = new JScrollPane(main,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scroll.setSize(500,500);
//Font
//Font david50 = new Font("David", Font.BOLD, 50);
for(int i=0; i<1000; i++)
{
JLabel empty = new JLabel("No jobs to display!");
empty.setBounds(0,i+250,400,100);
empty.setFont(david50);
main.add(empty);
}
add(main);
setVisible(true);
}
public static void main(String[] args) {
JobHistoryListScreen v = new JobHistoryListScreen();
v.showScreen();
}
}
For some reason the window gets filled with the labels but is not scrollable at all.
Learn about layout managers. Refer to Laying Out Components Within a Container. Default for JPanel is FlowLayout and because the JPanel is inside a JScrollPanel, the labels will not wrap. And since you set the horizontal scroll bar policy to NEVER, there is no horizontal scroll bar and hence you cannot scroll horizontally. Try using BoxLayout to display all the labels one under the other. Alternatively you could use a GridLayout with 0 (zero) rows and 1 (one) column. Refer to the tutorial for more details.
EDIT
Here is my modified version of your code. Explanatory notes appear after the code.
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.WindowConstants;
public class JobHistoryListScreen implements Runnable {
private JFrame frame;
#Override // java.lang.Runnable
public void run() {
showScreen();
}
public void showScreen() {
frame = new JFrame("Jobs");
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
JPanel main = new JPanel(new GridLayout(0, 1));
JScrollPane scroll = new JScrollPane(main,
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scroll.setPreferredSize(new Dimension(500, 500));
Font david50 = new Font("David", Font.BOLD, 50);
for(int i=0; i<1000; i++) {
JLabel empty = new JLabel("No jobs to display!");
empty.setFont(david50);
main.add(empty);
}
frame.add(scroll);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
JobHistoryListScreen v = new JobHistoryListScreen();
// Launch Event Dispatch Thread (EDT)
EventQueue.invokeLater(v);
}
}
I don't know what interface View is so I removed that part.
No need to extend class JFrame.
No need to explicitly call setSize() on JFrame. Better to call pack().
Default content pane for JFrame is JPanel and default layout manager for that JPanel is BorderLayout so no need to explicitly set.
No need to call setSize() on JPanel.
Call setPreferredSize() rather than setSize() on JScrollPane.
Add the JScrollPane to the JFrame and not the JPanel.
No need to call setBounds() because GridLayout handles this.
Explicitly launch EDT (Event Dispatch Thread) by calling invokeLater().
Here is a screen capture of the running app. Note the vertical scroll bar.
I'm trying to add an image to a JFrame and set its location, I don't know why it just does not add into it, maybe I don't understand how the JFrame class works since a normal text JLabel adds into the JFrame simply without any trouble and a JLabel containing an image simply does not add in.
I would appreciate if someone would explain the error in the code, and maybe even give me a short explanation of why my way does not work. Thanks!
import java.awt.*;
import javax.swing.*;
public class Walk {
public static void main(String[] args) {
JFrame f = new JFrame("Study");
f.setSize(3000,1000);
f.getContentPane().setBackground(Color.white);
f.getContentPane().add(new JLabel("test", JLabel.CENTER) );
JLabel l = new JLabel(new ImageIcon("C:\\Users\\leguy\\OneDrive\\Desktop\\Stuff\\stillsp"));
l.setBounds(100, 100, 100, 100);
l.setVisible(true);
f.add(l);
f.setVisible(true);
}
}
are you using a gui class or you are writing its code into a main class
what is in your code is that you are writing its code so easy way is to just drag and drop try this link for normal jframes gui eclipse gui
about the picture into jframe is easy one all what you have to do is
1. create a label by setting its size as you want on the jframe by dragging and dropping only
2. follow the pictures
then you browser for your picture you want
select the picture and its done
Hope it helps
Make sure the path to your image is valid. All I did was point to a valid image on my PC and the code practically worked. There were a few things added and organized below.
import java.awt.Color;
import javax.swing.*;
public class Walk {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() { // Safety first...
#Override
public void run() {
String path = "C:\\Path\\To\\Image.png"; // Make sure it's correct
JFrame frame = new JFrame("Study");
JLabel label = new JLabel(new ImageIcon(path));
frame.setSize(3000, 1000);
frame.getContentPane().setBackground(Color.white);
frame.getContentPane().add(new JLabel("test", JLabel.CENTER));
label.setBounds(100, 100, 100, 100);
label.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(label);
frame.pack(); // Pack the frame's components.
frame.setVisible(true);
}
});
}
}
To make sure both labels show up, provide a layout and add them accordingly.
import java.awt.*;
import javax.swing.*;
public class Walk {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
String path = "C:\\Path\\To\\Image.png"; // Make sure it's correct
JFrame frame = new JFrame("Study");
Container container = frame.getContentPane();
JLabel imageLbl = new JLabel(new ImageIcon(path));
JLabel textLbl = new JLabel("test");
frame.setLayout(new BorderLayout());
frame.setSize(3000, 1000);
imageLbl.setBounds(100, 100, 100, 100);
imageLbl.setVisible(true);
container.setBackground(Color.WHITE);
container.add(textLbl, BorderLayout.NORTH);
container.add(imageLbl, BorderLayout.CENTER);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
});
}
}
I'm trying to add the ScrollPane to my TextArea, but it doesn't appear.
Here's the code:
import javax.swing.*;
public class PracownikGui extends JFrame {
private JPanel Panelek;
private JTextArea Tekscik;
private JScrollPane Skrol;
public PracownikGui() {
setMinimumSize(new Dimension(600, 600));
setLocationRelativeTo(null);
setContentPane(Panelek);
setResizable(false);
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
Tekscik();
public void Tekscik() {
Tekscik = new JTextArea(2, 10);
Skrol = new JScrollPane( Tekscik );
Tekscik.setSize(300, 300);
Tekscik.setLocation(20, 70);
Tekscik.setEditable(true);
Tekscik.setLineWrap(true);
add(Tekscik);
}}
Any help, please.
You're shooting yourself in the foot by setting a JTextArea's size or preferredSize since this prevents it from expanding into the JScrollPane:
Tekscik.setSize(300, 300);
set its rows and columns only.
Also you need to add the JScrollPane to the GUI, not the JTextArea.
Also, while null layouts and setBounds() or setSize(...) and setLocation(...) might seem to Swing newbies like the easiest and best way to create complex GUI's, the more Swing GUI'S you create the more serious difficulties you will run into when using them. They won't resize your components when the GUI resizes, they are a royal witch to enhance or maintain, they fail completely when placed in scrollpanes, they look gawd-awful when viewed on all platforms or screen resolutions that are different from the original one.
e.g.,
import javax.swing.*;
public class PracownikPanel extends JPanel {
private JTextArea tekscik = new JTextArea(5, 25);
public PracownikPanel() {
tekscik.setLineWrap(true);
tekscik.setWrapStyleWord(true);
JScrollPane skrol = new JScrollPane(tekscik);
skrol.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
add(skrol);
}
private static void createAndShowGui() {
PracownikPanel mainPanel = new PracownikPanel();
JFrame frame = new JFrame("PracownikPanel");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
I made quite a few changes to your code. Your code wouldn't run.
Here's the GUI I created.
As you can see, there's a vertical scroll bar. The default action for the scroll bar is that it doesn't appear until you've filled the JTextArea with text.
Here are the important changes I made to your code.
Class names start with a capital letter. Method names and variable names start with a lower case letter.
A Swing application must start with a call to the SwingUtilities invokeLater method. This ensures that the Swing components are created and used on the Event Dispatch thread (EDT). Since the invokeLater method requires a Runnable, I had the PracownikGui class implement Runnable.
You use Swing components. You don't extend Swing components, or any other Java class, unless you want to override one of the methods in that class.
I removed all of the sizing and positioning statements, except for the statement that defines the rows and columns of the JTextArea. Hovercraft Full Of Eels explained this, but you use Swing layouts to get the arrangement of Swing components you want. The default layout for a JPanel is the FlowLayout. The default layout for a JFrame is the BorderLayout.
I added the JScrollPane to the JPanel. I added the JPanel to the JFrame.
Here's the code.
package com.ggl.testing;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
public class PracownikGui implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new PracownikGui());
}
private JFrame frame;
private JPanel panelek;
private JTextArea tekscik;
private JScrollPane skrol;
#Override
public void run() {
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
panelek = new JPanel();
tekscik(panelek);
frame.setContentPane(panelek);
frame.setResizable(false);
frame.pack();
frame.setVisible(true);
}
public void tekscik(JPanel panelek) {
tekscik = new JTextArea(2, 20);
tekscik.setEditable(true);
tekscik.setLineWrap(true);
skrol = new JScrollPane(tekscik);
panelek.add(skrol);
}
}
I am trying to make a JFrame with a button in it, but my button doesnt have my wanted text! I'm setting it in the button constructor AND afterwards with setText, but it still doesnt show up! Also, the button fills the whole frame, is there a way to make it not stick to the edges of the JFrame?
import javax.swing.*;
public class main
{
public static void main(String[] args)
{
JFrame mainWindow = new JFrame("8 Game");
mainWindow.setSize(200, 200);
JButton eightButton = new JButton("8");
eightButton.setText("8");
eightButton.setSize(30, 30);
eightButton.setBounds(5, 5, 25, 25);
eightButton.setContentAreaFilled(false);
eightButton.setAction(new buttonAction());
mainWindow.add(eightButton);
mainWindow.setVisible(true);
}
}
Why does it work for me and not you? (with the FlowLayout suggested by others
import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
public class main
{
public static void main(String[] args)
{
JFrame mainWindow = new JFrame("8 Game");
mainWindow.setLayout(new FlowLayout(FlowLayout.CENTER));
mainWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainWindow.setSize(200, 200);
JButton eightButton = new JButton("8");
eightButton.setText("8");
eightButton.setSize(30, 30);
eightButton.setBounds(5, 5, 25, 25);
//eightButton.setAction(new buttonAction());
//eightButton.setContentAreaFilled(false);
mainWindow.add(eightButton);
mainWindow.setVisible(true);
}
}
EDIT
an Action needs a title. If you don't specify one, the button will have no title. If you did this
eightButton.setAction(new buttonAction(), "8");
it would work.
Use a layout manager that respects the component's preferred size
mainWindow.setLayout(new FlowLayout(FlowLayout.CENTER));
Swing components expect a layout manager context when they are added to a window.
The default layout is BorderLayout, which is why you're getting that odd behavior. With only a single element, BorderLayout fills the pane with that element.
Try something like FlowLayout or AbsoluteLayout (or null)
http://docs.oracle.com/javase/tutorial/uiswing/layout/none.html
Use another LayoutManager default frame's layout manager is BorderLayout that if you add a component without specification will add to the center. You can use FlowLayout. See example with SwingUtilities.invokeLater you ensure that will run in EDT.
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame mainWindow = new JFrame("8 Game");
mainWindow .setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainWindow.setLayout(new FlowLayout());
mainWindow.setLocationRelativeTo(null);
JButton eightButton = new JButton("8");
eightButton.setText("8");
eightButton.setContentAreaFilled(false);
eightButton.setAction(new buttonAction());
mainWindow.add(eightButton);
mainWindow.pack();
mainWindow.setVisible(true);
}
});
}
Take a look of more complete correct examples in official tutorials How to use Buttons
I just can't get past square one on JLayeredPanes. (See my original question of yesterday. I have been studying the JLayeredPane tutorial and API. These tutorials are geared somewhat differently to what I am ultimately trying to produce.
Going back to square one, I took Oracle's JFrame Example and modified it to include Layered panes.
Here is the code:
package components;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/* FrameDemo.java requires no other files. */
public class FrameDemo {
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame("FrameDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel mainLayer = new JPanel(new BorderLayout());
mainLayer.setPreferredSize(new Dimension(640, 480));
frame.setContentPane(mainLayer);
frame.getLayeredPane().add(mainLayer, JLayeredPane.DEFAULT_LAYER, 0);
JLabel emptyLabel = new JLabel("LABEL");
emptyLabel.setPreferredSize(new Dimension(320, 240));
mainLayer.add(emptyLabel, BorderLayout.NORTH);
JPanel subLayer = new JPanel(new BorderLayout());
JLabel subLabel = new JLabel("SUBLABEL");
subLabel.setPreferredSize(new Dimension( 200, 100));
subLabel.setBackground(Color.YELLOW);
subLayer.add(subLabel, BorderLayout.SOUTH);
subLayer.setVisible(true);
subLabel.setVisible(true);
frame.getLayeredPane().add(subLayer, JLayeredPane.PALETTE_LAYER, 0);
//Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
Why doesn't it work? IOW, why doesn't the sublabel show up? It's at a higher level than the main layer.
One thought is why am I adding mainLayer to both the Content Pane and the Layered Pane? If I don't do that, nothing shows up. I.e, by commenting out this line, I just get a blank frame.
// frame.setContentPane(mainLayer);
Obviously, I'm not understanding something. But what is it?
I should add that obviously, this simple demo can be done without Layered Panes. But my ultimate goal is to have a layer that can be turned on and off programatically. But I can't even get this simple case to work. If I can get over this hump, I think the rest will be easier.
ADDENDUM:
What I want to acheive is illustrated by the following Code, which is very similar to what TrashGod set up below and it works. There is a JLayeredPane with a constant layer (layered at Integer(0)) and a floating layer layered initially at Integer(-1) but togglable by the F7 and F8 keystrokes between the Integer(-1) layer and the Integer(1) layer, thereby allowing it to float above or below the constant layer.
package components;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/* MyLayeredPaneDemo.java requires no other files. */
public class MyLayeredPaneDemo {
private JFrame frame;
private JLayeredPane mainPanel;
private JPanel constantLayer;
private JPanel floatingLayer;
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private MyLayeredPaneDemo() {}
private void createAndShowGUI() {
//Create and set up the window.
this.frame = new JFrame("MyLayeredPaneDemo");
this.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.frame.setPreferredSize(new Dimension(640, 480));
mainPanel = new JLayeredPane();
constantLayer = new JPanel(new BorderLayout(0,0));
floatingLayer = new JPanel(new BorderLayout(0,0));
// constantLayer.setPreferredSize();
constantLayer.setOpaque(true);
constantLayer.setBackground(Color.BLUE);
JLabel constantLabel = new JLabel("MAIN LAYER");
constantLayer.setPreferredSize(new Dimension(640, 480));
constantLayer.add(constantLabel, BorderLayout.CENTER);
JLabel subLabel = new JLabel("SUB LAYER");
floatingLayer.setBackground(Color.YELLOW);
floatingLayer.add(subLabel, BorderLayout.SOUTH);
floatingLayer.setOpaque(true);
floatingLayer.setVisible(true);
floatingLayer.setVisible(true);
subLabel.setBackground(Color.YELLOW);
mainPanel.add(constantLayer, new Integer(0), 0);
constantLayer.setBounds(0,0,640,480);
mainPanel.add(floatingLayer, new Integer(-1), 0);
floatingLayer.setBounds(100, 360, 300, 90 );
frame.add(mainPanel, BorderLayout.CENTER);
//Display the window.
mapKeyToAction(frame.getRootPane(),
JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT,
KeyStroke.getKeyStroke(KeyEvent.VK_F7, 0),
"Hide Layer",
new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("F7 pressed");
mainPanel.setLayer(floatingLayer, new Integer(-1));
}
});
mapKeyToAction(frame.getRootPane(),
JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT,
KeyStroke.getKeyStroke(KeyEvent.VK_F8, 0),
"Show Layer",
new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("F8 pressed");
mainPanel.setLayer(floatingLayer, new Integer(1));
}
});
frame.pack();
frame.setVisible(true);
frame.getRootPane().setFocusable(true);
boolean ok = frame.getRootPane().requestFocusInWindow();
System.out.println("focus ok: " + ok);
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
new MyLayeredPaneDemo().createAndShowGUI();
}
});
}
private static void mapKeyToAction(JComponent component,
int whichMap, KeyStroke keystroke,String key, Action action) {
component.getInputMap(whichMap).put(keystroke, key);
component.getActionMap().put(key, action);
}
}
However, I am having trouble getting this to work in my real case. The difference between the two is that here, my JLayeredPane is owned by the Frame, whereas in my real application, I want the JLayeredPane to be owned by a JPanel is that some levels down in the containment hierarchy from the Frame, and whose size is set by a GridBagLoyout in its parent, and the size is therefore unknowable at the time its constructor is called, making it difficult to call setBounds() which I need to do on a child of a JLayeredPane.
FURTHER ADDENDUM. I know that the Oracle Tutorials mention a case where Layouts rather than absolute positioning is used with a JLayeredPane. The difference between this case and mine is that in my case the layers occupy the same horizontal space on different layers, whereas in this case, the components on different layrers occupy different horizontal spaces. It's almost as if we need a 3D Layout Manager!
"By default, a layered pane has no layout manager."—How to Use Layered Panes
Addendum: I need to avoid using the Frame's layered pane and instead add a layered pane to the window.
Yes, The Root Pane is an instance of JRootPane, which contains a JLayeredPane. In particular, "The layered pane contains the menu bar and content pane, and enables Z-ordering of other components."
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class FrameDemo {
private static void createAndShowGUI() {
JFrame frame = new JFrame("FrameDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLayeredPane mainLayer = new JLayeredPane();
frame.add(mainLayer, BorderLayout.CENTER);
JLabel label = new JLabel("LABEL", JLabel.CENTER);
label.setBounds(100, 100, 200, 100);
label.setOpaque(true);
label.setBackground(Color.cyan);
mainLayer.add(label, 1);
JPanel subLayer = new JPanel(new BorderLayout());
JLabel subLabel = new JLabel("SUBLABEL", JLabel.CENTER);
subLabel.setBounds(20, 20, 200, 100);
subLabel.setOpaque(true);
subLabel.setBackground(Color.yellow);
subLayer.add(subLabel, BorderLayout.SOUTH);
mainLayer.add(subLabel, 2);
frame.pack();
frame.setSize(320, 240);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
createAndShowGUI();
}
});
}
}
The solution I came up and thanks to trashgod which I expect is good advice too is to implement ComponentListener and capture the component resize event. At that point you can get the actual bounds of the container and use it to set the actual bounds of the layer JPanels which are always in some fixed relation to the bounds of the component that contains them. It works.
Trashgod's solution would also work I believe but I have not tried it.