I've read through a dozen or so actionlistener/loop related questions here, but I'm not sure I've found my answer. I started on my first large Java project, a text RPG that's spiraled into around 5K lines of logic and game features which was functioning as intended using just the console - when I decided I'd try to build a Java swing GUI for it instead. Here's my problem:
I use a Room object which handles the description of where the player is at and also has an array of options for the player to choose next which it creates dynamically based on what cell the room's id is in on a csv file and what is beside it. I stopped outputting this to the console and instead started creating JButtons based on the options array like so:
public void showNarrate(){
add(dd,gridConstraints);
optionCopy.clear();
int i = 0;
for(JButton j : optionButtons){
//adding and formatting buttons to gridBagConstraint I also set actionCommand for each button to the triggerValue (ID of the next room which the button should take the player to)
}
//I tried using a copy of my JButton array here so I could have something to iterate over in actionListener after clearing out the original
//(Since it needs to be cleared so the next Room's buttons can be built after the player chooses an option)
for(JButton j : optionButtons){
optionCopy.add(j);
}
optionButtons.clear();
//dd is a seperate drawingComponent I used for outputting room descriptions which may be totally unnecessary at this point :/
dd.repaint();
setVisible(true);
}
Over in actionlistener (Same class) this is how I tried to swing it:
for(JButton j : optionCopy){
if(e.getActionCommand().equals(j.getActionCommand())){
Main.saveRoom = Main.currentRoom;
Main.currentRoom = j.getActionCommand();
System.out.println(Main.currentRoom);
}
}}
Then in my main class I call:
narrator.narrate(currentRoom, saveRoom); which takes care of some other logic concerning locked doors, encounters, etc.
Also in Main loop are some other methods related to autosave and tracking which rooms the player has visited. I know from other q/a i'v read on here that this is all pretty bad design, and I'm sttarting to understand that now, but my issue is this:
The first room of the game loads up fine, when I click a button it outputs to console(Just for testing) the correct trigger value of the room the button should be calling, so I'm getting that far, but how can I call the same method over again now?
-If I call narrate from actionListener it will wind up calling itself again and complain about ConcurrentModification.
-If I try to keep a loop going in my Main class it will keep looping and won't allow for the player to actually choose a button.
I've never used threads before, which I wonder might be the answer,and the closest thing to a related answer I've found is this:
Java: Method wait for ActionListener in another class
but I don't think moving actionListener to Main class would resolve my problem which is actionListener winding up calling itself recursively. And as for the observer-observable pattern... I just can't understand it :(
I appreciate any and all help, I've learned a LOT trying to make this thing work without seeking help as much as possible but this has stumped me.
Your loop in actionPerformed only checks whether a JButton exists in your optionList with the given actionCommand. However this can be done before actually doing something:
boolean contained = false;
for (JButton j : optionButtons)
if (j.getActionCommand().equals(e.getActionCommand()))
contained = true;
if (contained) {
// change room
}
now you can call narrate because you have finished iterating over the collection beforehand and will not get a ConcurrentModificationException
Related
im creating a game using java language. I am new to GUI. I want to be able to somehow loop a frame. For example, if the user pressed 2 players, the second frame should be able to show twice like "Player 1 name: " then after pressing enter "player 2 name: " should be the next one and then after pressing next another frame will show. I want to be able to update my GUI every time the enter button is clicked, and limit the update depending on how many players was chosen. The images shown below have different .java files
while(i < game.getnPlayers()) {
if (action.getActionCommand().equals("enter")) {
// codes
}
i++;
}
im trying to start with this code, but when i do. it doesnt get updated
I see you have tagged the post with IntelliJ-idea, so I am assuming you are using the GUI designer. Graphical user interfaces use listeners to listen for certain input (OnMouseClick, ActionListener and so on), and then performs methods you assign to the listener. I would suggest reading some documents or watching some videos on the topic before moving on with your game.
A source from oracle on writing Event listeners
A video on making Java Swing GUIs using IntelliJ
Hope this helps! Good luck!
On your GUI class you must have the button function. There you can create an function for when the button is pressed (in this case the "ENTER"), then you will see how many players were selected.
I have a problem about modify button background. I am using netbeans gui builder for build form. I am trying change button background when the second frame is open and turn it back when second frame close.
public void update(boolean x){
if(x==true){
circleButton.setOpaque(true);
circleButton.setBackground(new java.awt.Color(0, 0, 0));
System.out.println("testoutput");
}
}
this is my update method from first class.
I added window listener to second frame.
private void formWindowOpened(java.awt.event.WindowEvent evt) {
isitopen = true;
//this is first class which includes button
homework hwork = new homework();
hwork.update(isitopen);
System.out.println("testoutput2");
}
I got 2 testoutput but color of the button didn't change.
What can i do to fix this issue ?
You're creating a new homework object in your formWindowOpened(...) method, one completely unrelated to the homework object that is displayed, and changing the state of the new object will have no effect on the displayed one.
A simple and WRONG solution is to use static fields or methods.
Instead one simple solution is to give the calss with your formWindowOpened(...) method a valid reference to the displayed homework object, something that can be done with a constructor parameter or a setHomework(...) method.
A much better and even simpler solution:
Make the 2nd window a modal JDialog, not a JFrame
This way homework will know when the window is open and can set its own button colors. When the 2nd window opens, program flow in the calling class is put on hold, and only resumes when the 2nd window closes -- just like using a JOptionPane.
For more on this, please see The Use of Multiple JFrames, Good/Bad Practice?
As an aside, you will want to learn and use Java naming conventions. Variable names should all begin with a lower letter while class names with an upper case letter. Learning this and following this will allow us to better understand your code, and would allow you to better understand the code of others.
I have 5 classes for this project, Button Minefield GUI MenuBar Game.
Button is an individual mine cell.
Minefield contains a 2d array of buttons, and operations that concern all of the buttons.
GUI is the portion above the MineField grid, displaying the reset button, time lapsed and how many flags remain,
Game puts all of the other classes in Panels and places them in the applet. No game logic here.
Here is a screenshot of my applet
I'm having problems when it comes to using inheritance. If I can solve this issue, I can do the other problems too. It has to do with invoking a method in the super class.
One of my problems:
When a Button mine cell is right-clicked, the mouse listener picks it up and changes the text of the JButton to "F" for flag. However, I want to update the counter of how many flags are available, which is a variable in the Minefield class. Finally, I want the GUI class to listen for changes to that variable and update the JLabel.
In the MouseListener for Button:
if (e.getButton() == MouseEvent.BUTTON3)
{
advanceCurrentState();
if (currentState == "FLAG")
super.setNumFlagsRemaining(-1); //update the Minefields variable
}
Back in Minefield:
public void setNumFlagsRemaining(int delta)
{
numFlagsRemaining += delta;
}
But this doesn't work. When I am debugging, super.setNumFlagsRemaining(-1) is creating a new instance of Minefield and I cannot update the variable inside the super class. I thought that it would update the existing object of Minefield, but I read that Java does not pass by reference, so I was confused as how to do it. If you need to see additional code please say so, I tried to not clutter this post with 5 whole classes and say, "fix it".
You do not provide enough code so I can only guess here.
I think you are confused with key word super
It actually mean to call method from the super class which you had inherited.
I doubt that JButton inherits anything from your class Minefield. Usually it is in opposite way.
Also count of the fields is stored and displayed in the JLabel. So you, actually, have to call method of the class which has this JLabel and takes care of total count.
I've read through lots of the threads on paintComponent here, most of which making the point that it either is never or almost never necessary (or possible) to choose when paintComponent is called.
In my program, however, sometimes (only sometimes) paintComponent gets called before some of the objects it needs to paint have finished initializing or even sometimes before they've been created, triggering warnings- JOptionPane pop-ups, which surprisingly do not show any of the text they were hard-coded to display in their "message" area. I've read in other places that it's something to do with the EDT, and I've looked into some parts of that but I'm just getting confused. If the main purpose of the EDT is to update the gui, and by default pretty much everything will run in the EDT, then could I tell the program to run all the initialization and update functions in a different thread(s), which I somehow forcibly make run before the EDT runs?
What I'd ideally like to have happen is for paintComponent to wait until a certain point in my code to be run (after a bunch of update functions, regardless of what happens to the screen. After it does get called, it is followed by a pause in which relatively little is going on ( I had been using Thread.sleep() inside a while loop ) and which lasts until the user clicks something - at which point all the necessary functions are run again, followed by paintComponent afterwards, then the sleep() while loop, etc.
From what I understand, I think what I want isn't really possible, so my question is: Do you guys have any ideas of how to get around this?
EDIT:
So essentially the program is a college course planner, intended to make it easier for someone to plan out by semester all the courses they have to take before graduation, move those courses around (if possible), and see how all the courses are connected (prerequisites and such). When the program starts, it loads the list of necessary courses from a text file, then loads info about each course from a bunch of individual text files, and arranges them according to their prerequisites. Courses with no prerequisites go in the first semester, courses whose prerequisites have all been added to the first semester get added to the second, and so on until all the courses have been added. When paintComponent runs, it calls a function that assume all of each course's prerequisites exist on the schedule, and if it finds otherwise, it throws an error and displays a JOptionPane message box. When this happens during a normal run of the program (like if I manually add a course before adding its prerequisites), that all works and displays correctly. But sometimes that message box pops up when only some of the courses have been loaded (meaning control is still in the main constructor) and when it does so, the actual string message doesn't show up - only the actual pane, title and ok button do. Heres the line where I display the error box, so you can know that I'm not trying to display a string variable which has the potential of being empty.
JOptionPane.showMessageDialog(this,
"Course couldn't be loaded, partially >loaded\ncourses have been removed.",
"Error",
JOptionPane.OK_OPTION);
It is the "Course couldn't...been removed." part that doesn't get displayed. This is the only JOptionPane I display with the title "Error".
This post mentioned what sounds like the same thing happening, except I'm not using any of the things that poster had to fix. So possibly it's irrelevant but I'll add it just in case. JOptionPane.showMessageDialog() shows but without any message?
But to step back a bit, because that box popped up before all the courses had been added, it means that paintComponent was somehow called in the middle of the relevant JPanel's constructor, before a bunch of things had been initialized. I added a bunch of println() statements to make sure that that is true. Is it normal for that to happen, and if so, is there a way to fix it without simply using Andrew Thompson's advice?
After thinking though it a bit, I think that because the project is 3200 lines long and relies to a huge extent on text files, I'm really not sure how to ( or if I can) make a SSCCE for it..
If any specific pieces would be helpful I'll gladly add those but if this problem isn't clearly some standard issue I'm getting wrong, then I'll just add that flag and keep looking for bugs.
Thanks for your help
Declare a flag as a class attribute. Check it in the paint method. Change it at the end of the initialization.
class XandYandZ extends JComponent {
boolean initializationFinished = false;
public XandYandZ() {
// long initialisation..
initializationFinished = true;
}
public void paintComponent(Graphics g) {
if (!initializationFinished) return;
// .. paint ..
I wrote a simple little maze game for a terminal which repeatedly asks the user to do something (e.g. "In which direction would you like to go? [N/E/S/W]"). I have a navigate() method running in a loop that fires off these questions, stores their answers and does something depending on the answer.
public enum Dir (N, E, S, W);
public void navigate() {
Dir nextDir = utils.askDirection("Which way do you want to go?");
// Do stuff with answer, like changing position of user in maze
}
Now, I've written a simple GUI for my game. I deliberately put all the references to the terminal in a ConsoleUtils class which implements a Utils interface (this has methods like askQuestion()) - the idea being that I could create a GuiUtils class and have my game either as a terminal game or as a GUI game.
The problem is that the navigate method asks the user a question and then "waits" for the response, which the Utils class gives it by using a Scanner to read the newest line of input. However if I use Event Listeners for the new N/E/S/W buttons in my GUI, they fire off events regardless whether the navigate method has asked for one or not.
--> Image of GUI
Is there any way I can combine this or do I need to write a new navigate method for the GUI?
(To be honest, I'm also not entirely sure whether my GUI class should instantiate a game class, in which case the logic for navigate could end up in a GUI method anyway, or whether the game should have a GUI. I haven't written any code for the event listener either yet, since I'm not sure which class should be calling which. This is probably a separate question.)
Your text based game has a loop that repeatedly asks questions to gather user input. Swing provides this loop for you by continually executing Runnable blocks of code that have been posted to the EventQueue. For example, when the user presses a button labeled E, code is posted to the queue that invokes your ActionEvent implementation to handle your game's interpretation of the move east command.
For reference, a complete example of a very simple guessing game is examined here. In pseudocode, the corresponding text based game might look like this:
initialize
loop
prompt "Guess what color!"
get chosenColor
if chosenColor = actualColor
say "You win!"
reset game
else
say "Keep trying."
end loop
A more elaborate game cited there includes the original text-based source.