This is the problem, I have a class MainWindow that extends JFrame in one of the setup routines I set the layout of the class to a new CardLayout(). This all works fine but when I go to request the the layout from the JFrame and cast what it returns to a CardLayout I get errors because it is returning a BorderLayout. I think you get the picture from hear.
Please find some code below:
public MainWindow()
{
initWindow();
}
public void actionPerformed(ActionEvent e)
{
CardLayout m = (CardLayout)super.getLayout();
m.next(this);
}
private void initWindow()
{
super.getContentPane().setLayout(_mainLayout);
super.setTitle(_WINDOW_NAME);
super.setSize(_DEFAULT_WINDOW_SIZE);
super.setLocationRelativeTo(null);
super.setAlwaysOnTop(true);
super.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
super.setResizable(false);
init_buttons_panel();
super.add(_buttons_panel, "bpanel");
}
I see that the code is not perfect this is because I have been trying everything to trap the problem. Yes I realize casting like that is not good but this is just test code to prove the point. Oh and _mainLayout is you guessed it a CardLayout.
I have also read how to use card layout and my code does not do anything out of the ordinary.
First, you should not cast a layout like that, at least without making any verifications. You should use the instanceof keyword first, to check if it really is a CardLayout, to prevent the program from finishing abruptly.
Second, the problem is here:
public void actionPerformed(ActionEvent e)
{
CardLayout m = (CardLayout)super.getContentPane().getLayout();
m.next(this);
}
Basicly you were getting the layout of the JFrame, and not from the JFrame's content pane, which is the one you actually set to be a CardLayout.
super.getContentPane().setLayout(_mainLayout);
The code you posted doesn't help us since we don't have all the information. We don't know what the variable _mainLayout refers to.
I suggest you start by reading the section from the Swing tutorial How to Use Card Layout for a working example and a better designed program. For one thing there is no reason to extend JFrame since you haven't added any functionality.
The getLayout method of JFrame is inherited from Container and thus does not forward on the call to the JFrame's content pane. You could try using super.getContentPane().getLayout() instead of super.getLayout().
Related
I am trying to set gmailPasswordField.setVisible(true) & senderPasswordLabel.setVisible(true) if the JTextField is changed, but it's not working.
doc.addDocumentListener(
new DocumentListener() {
public void changedUpdate(DocumentEvent e) {
int minLengthEmail = "n#gmail.com".length();
if (countDocumentChangeLength > minLengthEmail) {
gmailPasswordField.setVisible(true); // Doesn't appear to do anything
senderPasswordLabel.setVisible(true); // Nor this
}
}
});
Did you add a System.out.println(...) to see if the code is being executed? This is a basic debugging technique to see if the code is executing as you expect.
The changedUpdate(...) method is invoked when you change an attribute of the text.
I suspect you want to implement the other DocumentListener methods so you will be notified when the "text" in the Document changes. Read the section from the Swing tutorial on How to Write a DocumentListener for more information and working examples.
Don't use the method setVisible(boolean). Use CardLayout instead.
Little howto:
Move your widgets, which visibility must be switched, into a new JPanel (layout panel).
Create another JPanel with CardLayout (card panel) and place the layout panel into it.
Place an empty JPanel into the card panel.
Make sure that the appropriate card is visible (in your case - the empty card).
Make another card visible when required (in your document listener).
I'm trying to set a variable to be a new JPanel and then add it once a button is pressed, but it is not working and I don't know why.
code:
private void nextButtonActionPerformed(java.awt.event.ActionEvent evt) {
remove(scriptPanel);
scriptPanel = new GemPanel();
add(scriptPanel);
validate();
repaint();
pack();
}
GemPanel is just a JPanel class I made. When I press the next button, it re-sizes the frame to be as small as possible and nothing actually happens. If I re-size it to normal, the original scriptPanel is still there.
What gives?
Instead of trying to remove and add entire panels, a better, less problem prone approach would be to use a CardLayout that will allow to swap views. You can see more at How to use Cardlayout
Also, by the looks of your method signature, it seems you're using the Netbeans builder too. You may also want to take a look at How to Use CardLayout with Netbeans Gui Builder
I have a Gui and a Game class, and I'm unable to update the gui from the game. I'm not using threads, but I've seen it update before, so that isn't the problem. The game logic is really simple, there is no need for threads. No matter how furiously I call repaint() and revalidate(), it doesn't work now, no matter where I put it.
class Gui {
//...
public Gui(Game game) {
this.game = game;
initialize();
}
private void initialize() {
//...
okButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
okAction(textField.getText());
textField.setVisible(false);
okButton.setVisible(false);
textField.setText("");
}
});
}
private void okAction(String input) {
game.receiveInput(input);
}
public void output(String msg) {
textArea.append(msg + "\n");
}
public void getInput() {
textField.setVisible(true);
okButton.setVisible(true);
textField.setText("");
}
}
Also I want to be able to pass a String back to the game instance. I thought I'd call getInput() from the game, which will show a JTextField to type in, and a JButton to submit. In the actionPerformed() method I would just get the text entered, and call a method back in the game class. I don't know if this would work, since the gui is not updating, and I never had the input field and button appear. Is this right?
This would be the method which the gui "calls back":
class Game {
//...
public void receiveInput(String input) {
int n = Integer.parseInt(input);
if ( validInput(input, actualDecision.choices.size()) ) {
parser.setAction(actualDecision.choices.get(n-1).action);
}
}
}
From the game class, I just want to call gui.output() and gui.getInput() a few times.
Where is my problem? Why isn't it updating, nor freezing? If I use the debugger, the both output() and getInput() is executed, but nothing happens...
EDIT:
Ok I see a problem myself, with the getting input part... Since it returns quickly, it can never receive an input. But that doesn't explain why aren't the input field and the button, or any text is showing up
EDIT 2:
Oh god, sorry, I really don't know how to make it shorter, but you only ever need to look at the Game and the Gui, others are just there to compile.
The code: https://gist.github.com/anonymous/53bad714592792316b4d
An xml to test against: https://gist.github.com/anonymous/30b56facb78fe6ecd482
Honestly I have just taken a look to Gui class code and don't know why it doesn't update properly when it interacts with Game class. BUT I have several remarks on your code and I hope these can lead you in the right way by making this class simpler and then you can focus on the interaction with Game class.
Menu bar
You're adding the JMenuBar to a JPanel instead of setting it to the JFrame:
panel.add(menuBar, gbc);
//frame.setJMenuBar(menuBar); Use this instead
As JFrame is a top level container prepared to handle a menu bar you should consider make the suggested change.
Saving validate() call
As the JFrame is initialized at the start of initialize() method and the JPanel is added after making the frame visible then you have to call frame.revalidate() method to revalidate the components hierarchy. If you just initialize the panel before make the frame visible then you don't need to call revalidate() method. Take a look to this answer for further details.
Missing pack() call
There's no call to frame.pack() method to lay out the frame's subcomponents. Take a look to Window.pack().
Missing GridBagConstraints when adding okButton
There's no GridBagConstraints as argument when adding okButton to panel:
panel.add(okButton);
//panel.add(okButton, gbc); This is the correct way.
Use of setSize()
In this line:
frame.setSize(800, 600);
We should avoid using set(Preferred | Minimum | Maximum)Size() because of reasons discussed in this topic: Should I avoid the use of set(Preferred|Maximum|Minimum)Size methods in Java Swing?
Use of GridBagLayout
This is just a suggestion there's nothing wrong on how you are using GridBagLayout. As probably you have noted this layout manager is a little hard to use (and I really don't like it by the way :) You can use a Nested Layout approach to make the components layout easier and your code more readable. Maybe this approach is good enough:
Set the JMenuBar to the JFrame. It's one less component to lay out
;)
Add the scroll pane with the text area directly to the frame's
content pane using
BorderLayout
constraints: frame.getContentPane().add(scrollPane,
BorderLayout.CENTER);
Create a new JPanel to hold the text field and the button used to
ask for user's input and add it to the frame's content pane.
Translated to code:
JPanel usersInput = new JPanel(new FlowLayout(FlowLayout.CENTER));
usersInput.add(textField);
usersInput.add(okButton);
frame = new JFrame();
frame.setJMenuBar(menuBar);
frame.getContentPane().add(scrollPane, BorderLayout.CENTER);
frame.getContentPane().add(usersInput, BorderLayout.SOUTH);
frame.setTitle("Choose your own adventure");
frame.pack();
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); // It's better practice DISPOSE_ON_CLOSE ;)
frame.setVisible(true);
Update
Well I'm curious and I really want to test your game (quite nice work by the way :) The thing is I have found at least two problems in the logic:
Use of == to compare strings
In Parser class there are several string comparisons using == but this is not the proper way to compare strings. We must use .equals() method to compare strings equality. Take a look to this topic: How do I compare strings in Java?
Game.processStory() has an endless loop
This method has an endless loop here:
while ( !end() ) { // this condition never is false so the loop is infinite
...
}
Looking closer to Game.end() method I have found an incorrect string comparison:
private boolean end() {
return ( parser.getAction() == "end" );
//It should be: return parser.getAction().equals("end");
}
But fixing that doesn't solve the problem either: it turns parser.getAction() always returns "d1" and consequently it will never be equal to "end".
Having said this as Game.play() is executed in the Event Dispatching Thread (a.k.a. EDT) triggered by newGameItem menu item and Game.processStory() has this endless loop, then the EDT is getting blocked and Gui is never updated.
In this case I would suggest you take a look to Concurrency in Swing trail to learn about how to avoid blocking the EDT.
I am developing a game, where you first get to the main screen, there are multiple selections to go, for example, Singleplayer, Twoplayer, Credits, etc.
I have one big problem. If I click a button in the menu, (not JButton) the JPanels switch, but the keyListener is lost. The Keylistener is in the same class as the game code, which implements JPanel. I tried everything to get the Keylistener to work, but it just won't.
Here is how the things are called: Main class --> Menu --> Game. I tried adding the keylistener to the main class, but it's not working.
So, JPanel switching is ok, but the Keylisteners are gone. I was developing the game before with new JFrames, so when I clicked a menu, a new frame was created. I didn't insert a code here, because it's too long (2000+ lines), and the KeyListener is working, but only when it is in a new JFrame. I set the mode int in the Menu class, by clicking a button.
This is currently my panel switch:
public void setJPanel() {
switch (mode) {
case 1:
getContentPane().add(s);
validate();
break;
case 2:
getContentPane().removeAll();
getContentPane().add(sp);
validate();
break;
}
}
Thanks for your help in advance!
Rather than use a KeyListener, have you given thought to or tried using Key Bindings? KeyListeners require that the component being listened to has focus, and focus may be lost for many reasons, especially when swapping views (are you using a CardLayout for this?). Key Bindings on the other hand can be set to be responsive even if the bound component doesn't have focus but when it is only held within a window that has focus. Tutorial: Using a CardLayout
Edit
I see that you're not using a CardLayout, and I suggest that you use this as it can make your view swapping cleaner and easier.
Edit 2
I agree that you don't want to post your entire 2000+ line program here as no one will have the time to read it, but consider condensing your question/problem into a single small class that is compilable and runnable by any and all of us, and demonstrates your problem. In other words, a Short, Self Contained, Compilable, Example or SSCCE .
Remember, the code should be compilable and runnable for many of us to be able to understand it fully.
Cardlayout actually is screwy while refocusing.
#op, try calling requestFocusInWindow() after the new jpanel was added
Try using myPanel.requsetFocusInWindow();
before using setVisible(true);
class Deal implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
dl.setDeck();
dl.shuffle();
dl.firstDraw(pl);
for(Card c:pl.showHand())
panelplay.add(new JLabel(c.getImageIcon()));
panelplay.validate();
}
}
This is an event handler for a Jbutton. The method pl.showHand() returns a ArrayList of a user defined class 'Card'. Inserting a println() inside the loop shows the print, so the code is being executed but the Panel panelplay isnt showing card Images.
What about the existing labels on the panel? You don't remove them. I'm guessing you are using a FlowLayout and the labels just get added to the end of the panel so you don't see them.
So one solution is to use panel.removeAll() before adding the labels back to the panel. I then use:
panel.revalidate();
panel.repaint();
Or the better option as suggested earlier is to not replace the labels but just replace the Icons using the setIcon() method.
Do as Gilbert says, look at the Swing Tutorial part that concerns Labels.
JLabel has the following methods...
void setIcon(Icon)
Icon getIcon()
Also look at the SplitPaneDemo It does exactly what you want, you can even run it with JNLP to see.
You don't want to add the JLabel in the ActionListener.
You want to use an already added JLabel setText() method in the ActionListener.
You define all the Swing components once, when you create the GUI.