I have a problem.
I have a JFrame with some JTextFields, JLabels, Jlists & JButtons now the contents of my frame is more than the screen area so I want to attach a JScrollBar to my JFrame but my srollbar does not work. So, can anyone please guide me on how I can scroll my JFrame using the JScrollbar?
Put all the components in one panel (instead of in the JFrame)
Add this panel to a JScrollPane
Add the JScrollPane to your frame.
I should be something like:
JPanel container = new JPanel();
container.add(panel1);
container.add(Panel2);
JScrollPane jsp = new JScrollPane(container);
frame.add(jsp);
It depends on the layout you are using with your JFrame. If you want to add working scrollbar to your panel you should look at the JScrollPane class and the Scrollable interface which must be implemented by scrollable components.
The How to use scroll panes chapter in the swing tutorial may also be an interesting reading: http://download.oracle.com/javase/tutorial/uiswing/components/scrollpane.html
Related
I need to know which method gives you the panel panelA from my scrollpane.
For example, I have:
PanelExample panelA = new PanelExample();
JScrollPane scrollpane = new JScrollPane(panelA,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scrollpane.getPanel(); //???
scrollpane.getComponent(); //???
I guess it should be a get method, but I don't know.
You get the component from the JViewport of the JScrollPane:
Component c = scrollPane.getViewport().getView();
Read the section from the Swing tutorial on How to Use Scroll Panes for information on how the scroll pane works and the components involved in the layout of the scroll pane.
I have a 2 JPanels, 1 a button Panel and one a Graphic Panel. I would like the button panel to situated right below the graphic panel but the button panel cuts off the Graphics Panel in the middle. I've been trying the box layout which seems from discussions seems like the best format for what I am trying to do. Can anyone please give me some advice on my formatting problem.
JFrame canvas = new JFrame("Baseball Strike K");
JFrame canvas = new JFrame ("GraphicBoard");
canvas.setVisible(true);
canvas.setSize(1000,1000);
canvas.setDefaultCloseOperation(EXIT_ON_CLOSE);
//create two panels
//add them to contentPane
//set Layout
JPanel buttonPanel = createButtons();
JPanel mainPanel = new Graphic(); //extends JPanel and writes the paint method
mainPanel.setSize(1000, 1000);
Container content = canvas.getContentPane();
content.setLayout(new BoxLayout(content, BoxLayout.Y_AXIS));
content.add(mainPanel);
content.add(buttonPanel);
mainPanel.setSize(1000, 1000);
The job of the layout manager is to determine the size of the component, so you would never invoke the setSize() method of a components.
Instead you give hints to the layout manager on what the size should be. You would do this by overriding the getPreferredSize() method to return an appropriate value. Also, I would pick a more reasonable size (1000, 1000) is a little big to display on most screens. If you really want your painting area this large then I would add the paint panel to a JScrollPane and then add the scrollpane to the frame.
Try getting your code to work using a BoxLayout. Then I would suggest a better layout manager would be to use a BorderLayout. Then you add the paint panel to the CENTER and the buttons to the SOUTH. Now as you resize the frame the paint panel will be adjusted in size.
canvas.setVisible(true);
Also, the placement of that line of code is wrong. You should add all your components to the frame first, before making the frame visible.
I have been trying to use JScrollPane with my applet, but it doesn't work. I have a JPanel to which I add 20 buttons, and I want to be able to scroll up and down this JPanel. Instead, the scrollbars do not appear. When I use setPreferredSize they still did not appear even though only about 3 of the buttons are being displayed and the rest are cut off. If I do not use setPreferredSize, there might as well not be any scrollbars because I have to make the window big enough to see all of the buttons. If I try to make the scrollbars always visible, they appear but do nothing. I tried the exact same code with JFrame instead of Applet, and it works fine, but I need it to be an applet. Is JScrollPane incompatible with applets? (Note: I tried to use an outer JPanel and add the scrollable panel to it, but it changed nothing). Changing the layouts also doesn't fix the problem. I have attached a simplified version of my code, but it displays the same errors.
Here is the code I have:
JPanel scrollPanel = new JPanel();
scrollPanel.setLayout(new BoxLayout(scrollPanel, BoxLayout.PAGE_AXIS));
JScrollPane scroll = new JScrollPane(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
for (int i = 0; i < 20; i++) scrollPanel.add(new JButton("Button " + i));
add(scrollPanel);
validate();
You never all the panel to the scroll pane
You never add the scroll pane to the applet
The basic code should be:
JScrollPane scrollPane = new JScrollPane(...);
scrollPane.setViewportView( scrollPanel );
add( scrollPane );
You are adding components to a Panel so you shouldn't expect to see a scroll pane wihout showing the scrollpane. What you want to do is then add that panel to a scrollpane which would be added to ur main container.
From your code, i think your problem is
add(scrollPanel);
your should be doing this
add(scroll);`
This is because you only added the panel to the frame which does not contain any scrollpane. Since you have added the panel unto the scrollpane, you should add the scrollpane and not the panel to the main container.
It sounds like you are using Swing components (JScrollPane, JPanel, ...) in an AWT container (Applet). Try using JApplet instead.
I have a simple swing application which consists of a JLabel and three buttons. The three buttons are in their own JPanel which is in a JFrame along with the JLabel. The JPanel uses flowlayout manager to arrange the buttons horizontally and the JFrame uses the BorderLayout manager to arrange the JLabel and JPanel vertically.
My problem is when I launch the application, during the course of use the text on one of the buttons changes which increases its width. However, the window doesn't resize to accomdate this and one of the buttons disappears. I thought about calling pack() again, but the JFrame is a local variable in my constructor, also, I shouldn't have to tell my program to resize, right? I haven't been able to find anything on google or here to help me but there must be a simple solution, what am I missing? Code is below.
playButton = new JButton("Play");
pauseButton = new JButton("Pause");
stopButton = new JButton("Stop");
curTrackLabel = new JLabel("No Track Selected");
JFrame myFrame = new JFrame("MediaPlayer");
myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
myFrame.setTitle("MediaPlayer");
myFrame.setLocation(400,300);
JPanel topPanel = new JPanel();
topPanel.setLayout(new BorderLayout());
myFrame.add(topPanel);
JPanel buttonPanel = new JPanel(new FlowLayout());
buttonPanel.add(playButton);
buttonPanel.add(pauseButton);
buttonPanel.add(stopButton);
topPanel.add(buttonPanel, BorderLayout.CENTER);
topPanel.add(curTrackLabel, BorderLayout.NORTH);
playButton.addActionListener(new playButtonHandler());
pauseButton.addActionListener(new pauseButtonHandler());
stopButton.addActionListener(new stopButtonHandler());
myFrame.pack();
myFrame.setVisible(true);
Maybe try
((JFrame)myButton.getTopLevelAncestor()).pack();
Where myButton is the button whose text is modified during execution.
As with learning any GUI software, experimentation is best. Try messing with BorderLayouts with nested JPanels.
Ultimately, you use JPanel with a BorderLayout (Flow Layout is OK but really when resizing the window, it epically fails). See http://download.oracle.com/javase/tutorial/uiswing/layout/border.html to learn more about BorderLayouts.
Now for your layout scheme it should be something along the lines of:
Top Level Container: JFrame
JFrame contains a JPanel (Call this
JPanel 1) with a BorderLayout.
The three buttons should be in a
SEPARATE jPanel (JPanel 2). JPanel
1 should add the three buttons as
BorderLayout.CENTER. In this way,
the window will resize if the button
changes its width and/or hright.
The JLabel should be added as
BorderLayout.LINE_START.
The tutorial at: http://download.oracle.com/javase/tutorial/uiswing/layout/border.html should help you with this. But in general, use the following:
Use JPanel and nest JPanels as necessary
BorderLayout.CENTER will accomodate size changes---this is the key! (Experiment with this)
JFrame should only be used as a top level container (for more complex GUIs, this is true).
If you require more flexibility, check out JGoodies: http://www.jgoodies.com/ . This is more along the lines of creating forms.
I have a JFrame with a JPanel on it.
I want to add another JPanel which is a preconfigured component onto the Jpanel inside my JFrame.
If I do this:
subPanel.setLayout(new BorderLayout());
subPanel.add(preconfiguredPanel,BorderLayout.CENTER);
my Panel will show.
If I do this:
subPanel.add(preconfiguredPanel);
my JPanel will not show. The documentation says when using add(Component) it will use the default Layout FlowLayout. Ok fine, but why won't my component display inside that JPanel when using the default FlowLayout???
Probably because your panel doesn't have a preferred size.
When you add a panel to a BorderLayout the default is to place it in the center, so the panel will automatically be resized to the size of the frame.
When you add the panel to a FlowLayout, the flow layout repsects the size of the panel.
If you need more help then post your SSCCE.