I'm creating a simple java game Applet that has multiple Panels, The main game Panel has 4 JButtons that lead to the rest of the Panels when they are clicked.
when the program runs, the four Panels are initialized 1st inside the init(), and inside each Panel initialization, I made all the Jcomponents invisible but only the main applet.
lets say there is a JButton in the main Applet Called start, when it's pressed, i need to set all the main JButtons to invisible, and set the sub Panel to visible but it's not working for me, I used everything I could think of, like repaint() or UpdateUI() but still not working.
any suggestions would be much appreciated.
Cheers
First, ensure all creation is performed not in init(), but in the EDT, see the tutorial. If you have an ampty start() method I'd recommend you use invokeLater in the init() (instead of the tutorial recommendation of invokeAndWait).
To hide buttons simply call setVisible on the JButton. There should be no need to ask for a repaint afterwards.
Further analysis is difficult without seeing the code.
Related
I realize it's pointless to include a button that would do the exact same thing as the 'x' in the window, but I've already worked out the placement of my buttons on my GUI and found having the exit button made things much easier if nothing but a placeholder. And I like the practice.
Ok anyways moving on.
I have a parent JFrame (main class actually) that I'd like to keep running open the entire time the program is being run. This isn't my issue. My problem is when opening a child JFrame. I instantiate it in the main class (it's adding a panel component I created) and I just can't figure out how close said JFrame from within the Panel. Is there an easy way of doing so? I already have the WindowConstant set to Dispose on Close.
What I've done so far is created a method getExit() which returns a boolean value of true. I then have in the main class where the JFrame was instantiated an if/else if statement telling it to set the JFrame visible if exit is False, and dispose of it if true. Doesn't do anything. I'm guessing that's because either it's not bothering to check at all or I coded it poorly.
Any advice?
EDIT: Clarifying what my code is so far without posting it (600 lines of crap to get through). I have my main class Driver(). It's the fairly straight forward main JFrame 'form'.
Said class has several buttons to open up a new JFrame that performs a simple function. We'll name one of those classes (only have 3 total for the Secondary JFrames) Panel(int type) It extends JPanel.
I have a constructor set up depending that takes the int type and hides certain components in my Panel (tried to maximize the panel by combining similar functions). I have a button on the panel that is an exit button. But because the class itself is not a JFrame and does not instantiate itself, I can't dispose of it there. I have to find a way to do so in the main class.
That is my issue.
See Closing an Application. You can use the ExitAction for your JButton and it will be just like clicking the close button of the frame.
I create a little program that load a frame in which I added some panels.
When I click on some button it should show some panels and hide other.
I'm experiencing some difficult to do it, even because I don't really figure out the diference between setVisible(true), repaint() and validate() (that some friends of mine suggested to me).
I hope you can make me to understand!
Thank you.
Carefully read the API for JComponent. The usages are:
setVisible - it will hide or show your component altogether. If you set it as false, you won't see it at all.
repaint() - is called when the actual pixels need to be redrawn, this is done automatically. It's used, for example, when you move a window on top of your GUI and then move it away. The part that was covered needs to be redrawn.
validate() - you should call this when the layout of your GUI has changed and you need the manager to replace and redraw your GUI.
It's a bit more complicated than that, so again, carefully read the API.
setVisible(true): sets the component so that it's visible.
repaint(): calls the paint method on the component.
revalidate(): updates the component based on the root component
I am debugging a Java Swing application in which a component (in my case a JButton inside a JPanel inside a JPanel) does not get repainted automatically when it should. For example, when the window is first shown, one can see the JButton there, but when another window overlaps my application's window for a while, the JButton can no longer be seen.
Since I have no idea where to begin, I would like to know what are the most common causes of repainting problems in Swing components.
This would be a good place to start at http://docs.oracle.com/javase/tutorial/uiswing/painting/problems.html
what happens if you minimize both the windows and bring them back on?
you might try calling your jpanel.revalidate() at some point in your code. But I don't know where to call that unless I see your code.
For a school project I'm writing a BlackJack card game in JAVA.
After a few steps within the program, my whole computer system slows down/stutters and some areas within the JFrame turn black. No repainting seems te be happening.
I will give you some program details in words rather then submitting the code.
I have done some extensive extending of almost every GUI component to give it the look and feel that I want. Almost every child of JComponent that I use has got its paintComponent rewriten with custom image backgrounds and anti-aliasing where applicable.
In my (custom) JFrame I load an extended version of JPanel. This panel holds all the GUI components for that screen. When I want to switch screen (go to a different part of the program), I switch to another extended version of JPanel. I do this by removing all elements from the JFrame and add the new panel. These different panels implements ActionListeners and FocusListeners.
At this point my thoughts are leaning towards a thread handling issue. My theory for the moment is this: When a panel is constructed for display in the JFrame (each on different stages within te program), the previous constructed panels aren't realy 'destroyed', and the Listeners of those panels remain active.
My question for you people is, wether this theory holds ground... And in that case, is there a way to 'kill' these panels or at least stop the listening?
If my theory doesn't make sense, what else could be causing these symptoms? Could it be the extensive overwriting of the paintComponent methods?
Any ideas would be highly appriciated!
Regards Wilco
When a panel is constructed for display in the JFrame (each on different stages within te program), the previous constructed panels aren't realy 'destroyed', and the Listeners of those panels remain active.
No. Events are only dispatched to the component that has focus. It a comonents doesn't have focus then it won't received system generated events like KeyEvents and MouseEvents. So if a panel isn't visible then it won't receive events.
I switch to another extended version of JPanel. I do this by removing all elements from the JFrame and add the new panel.
This is not the best design. It is better to use a Card Layout which was designed for this purpose.
Almost every child of JComponent that I use has got its paintComponent rewriten with custom image backgrounds and anti-aliasing where applicable
Then you probably have problems with your custom painting. What happens when you just use the standard components without custom painting?
I have several JPanels that contain buttons, labels, etc. that I want to switch between from a main JFrame. Currently I am trying to use the this.add(JPanelname); method and this.remove(JPanelname); with the validate(); and repaint(); methods
The problem is it will add the panel to the JFrame but it will not remove it. I am not sure how exactly to go about this.
Maybe you should be using a Card Layout.
Or maybe you should be using modal JDialogs. So whenever you click on the "widjet" a new window is displayed. Then when you close the dialog you are back on your main frame.
If you are constantly switching between JPanels, then a JTabbedPane may be the right thing to use. It should not be necessary to call "validate" or "repaint" when you add or remove a JPanel. Do you have a layout manager installed? Do you make sure to call add/remove only within the UI event thread? Also, typically one does not call "validate()" but rather "invalidate()" to invalidate the container for updates.