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How to rewrite the text of buttons that are not separately defined

I have started trying to write a code similar to the game 2048, however the size of the board can have any value depending on what the user inputs. I decided to make the numbers on the board, for style purposes, separate buttons.
This is the current GUI:
How can I make it so that when the buttons: up, down left, or right are pressed each of the button's in the board texts are changed? I know about event listeners I just mean how can I replace the button's in the same grid with different values when I defined the buttons on the board as:
`for(int i = 2; i < rows + 2; i++) {
for(int j = 2; j < columns + 2; j++) {
gbc.gridx = j;
gbc.gridy = i;
num = new JButton(board.board[j-2][i-2].getValue()+"");
num.setFont(new Font("monospaced", Font.PLAIN, screenSize.height/50));
num.setEnabled(false);
this.add(num, gbc);
}
}`
The only ideas I've had was to create an array of buttons and then change the button's text in the array of buttons and then replace the old array of buttons with the new one. Also sorry if it has some super simple answer that I just couldn't find, I am just about finished with one semester of coding courses in college.

You could store the JButtons on a HashMap and use column number and row number as a key to find the correct button.
Something like:
Map<String, JButton> grid = new HashMap<String, JButton>;
for(int i = 2; i < rows + 2; i++) {
for(int j = 2; j < columns + 2; j++) {
grid.put(String.valueOf(i) + String.valueOf(i), new JButton("some text"));
// we transform the integers into String, otherwise the operator "+" will sum them
// instead of concatenate them.
}
}
Now you cant get the desired button with grid.get(row + column);
JButton bt;
JButton bt = grid.get("4" + "6");
bt.setText("different text");
grid.put("4" + "6", bt);

I don't think you should use Buttons to do such a game button it's something that you can click on it since your are not supposed to click on numbers. If I were you I would use a gamePanel which contains fixed labels since it's easier changing text of label than moving label.
I would add MouseListener to the gamePanel and then fill implemented methods in order to manage when the mouse left button is pressed and move to left and so on.
So create an array of Label.
Create a method which add and move numbers according to the direction of the move. For instance if you make a left to right move you will start to add the numbers of the first column into the second column when they have same values. Next you just have to do it recursively until the last column.
If you need a bit more explainations ,I'll be pleased to help you.

Render multiple heights in an isometric tile based map

Good evening everyone.
I've been messing a bit with isometric tile worlds and I have a few doubts about rendering the elements on it.
When I build a single height map I render it first and then add the diferent elements on top, and the displacement of the last seem right.
public void render(Graphics2D g2d) {
for(int i = 0; i < tileGrid.length; i++) {
Point isop = NeoMath.getInstance().cartToIso(i % yAmmount, i / yAmmount, GlobalDataStorage.tileWidth, GlobalDataStorage.tileHeight);
TileManager.getInstance().getTileByID(tileGrid[i]).render(g2d, isop.x, isop.y);
}
for(Entity entity : entityList) {
entity.render(g2d);
}
}
(The position of the entity is calculated inside it's update).
With this I have no problems as everything is rendered on the same height, the problem comes when I try to add other floors to it.
Let's say that I want it to have three heights. I have a list of list of tiles instead of the single array, and render every element on them:
public void render(Graphics2D g2d) {
int flag = 0;
for(int i = 0; i < tileGrid.size(); i++) {
Point isop = NeoMath.getInstance().cartToIso(i % yAmmount, i / yAmmount, GlobalDataStorage.tileWidth, GlobalDataStorage.tileHeight);
for(int k = 0; k < tileGrid.get(i).size(); k++) {
TileManager.getInstance().getTileByID(tileGrid.get(i).get(k)).render(g2d, isop.x, isop.y - (GlobalDataStorage.tileZ * k));
}
while(flag < currentList.size() &&
currentList.get(flag).getPosition().equals(new Point(i % yAmmount, i /
yAmmount))) {
currentList.get(flag).render(g2d);
flag++;
}
}
}
Where the currentList is the list of entities.
With this I have the problem that, when the entities move to a new position, they get overlaped by the tiles, as these are rendered after the entity, and the position of the entity does not change until it reached the destiny. I could change the position to the new one before rendering, but that implies that in the other axis the previous tile get rendered after the entity, making it disapear for a second due to the overlap.
This also mess when I try to draw selection rectangle as it get stuck behind the tiles being rendered. I don't want them to overlap the whole map so can't draw them after all the rendering has been done either.
Does someone know of another approach that I can try out?
Thank you beforehand.

Draw your entire floor layer in a first pass. Then in the second pass draw all walls and objects and moving entities.
I could change the position to the new one before rendering,
David Brevik, programmer on Diablo, mentions using this option in his GDC talk Diablo: A Classic Games Postmortem. It was his first "What Went Wrong" example!
Reference: https://www.youtube.com/watch?v=VscdPA6sUkc&t=20m17s
Turns out this is a classic hurdle in isometric games.

Gridbag layout or Grid layout?

I am a little new to swing. In order to learn to use the API correctly, I am designing the following project:
The project is a solving block puzzle solver sliding block puzzle similar to the rush-hour puzzles common in toy stores - https://en.wikipedia.org/wiki/Rush_Hour_(board_game) except there is no escape for a special car.
By dragging the blocks from an off board area to the board, the user specifies the starting configuration of the puzzle. The user, in the same way, specifies an ending goal configuration which dictates where some (or all) of the blocks the user specified initially must be at the end of the puzzle - the ending configuration can be specified using only SOME of the blocks, making multiple legal ending configurations.
The algorithm for solving the puzzle is already complete - I just need to design the interface and I am getting stuck. For designing the tray, I used a grid layout. Since blocks need to be entered at certain positions, I need to be able to place blocks in specific cells in the grid and move them around.
A 'block' object has four attributes - its height, width, its top row, and its left most column (ie - each block is addressed by its top left corner).
I used the suggestion here ( https://stackoverflow.com/questions/2510159/can-i-add-a-component-to-a-specific-grid-cell-when-a-gridlayout-is-used ) for the grid layout.
Right now I have only programmed to the point where java reads the puzzle from a .txt file and is supposed to display it on the screen ( I have not designed any user interactablity yet ).
First, here is the code I have written so far.
public class SolverPuzzleGUI extends JFrame {
//Specs from the puzzle.
Board initBoard;
ArrayList<Block> goalBlocks;
LinkedList<Move> moveList;
JLayeredPane layeredpane;
JPanel Board;
Dimension boardsize = new Dimension(400, 500);
JPanel[][] panelHolder = new JPanel[5][4];
public SolverPuzzleGUI(Board startBoard, ArrayList<Block> startGoalBlocks,
LinkedList<Move> startMoveList) {
this.initBoard = startBoard;
this.goalBlocks = startGoalBlocks;
this.moveList = startMoveList;
} // end constructor.
//gives the actual simulation
public void runSimulation() {
// Initalizing the main window.
setSize(500, 600);
setName("Solution");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setMinimumSize(getMinimumSize());
//Using layered pane
layeredpane = new JLayeredPane();
add(layeredpane);
layeredpane.setPreferredSize(boardsize);
layeredpane.setBackground(Color.YELLOW);
layeredpane.setVisible(true);
// adding the game tray
Board = new JPanel();
layeredpane.add(Board, JLayeredPane.DEFAULT_LAYER);
Board.setLayout(new GridLayout(5, 4));
// centering the game tray.
Board.setPreferredSize(boardsize);
Board.setMinimumSize(boardsize);
Board.setMaximumSize(boardsize);
Box box = new Box(BoxLayout.Y_AXIS);
box.add(Box.createVerticalGlue());
box.add(Board);
box.add(Box.createVerticalGlue());
add(box);
//Adding placeholders to the board for creating blocks
for (int i = 0; i < 5; i++) {
for (int j = 0; j < 4; j++) {
panelHolder[i][j] = new JPanel();
panelHolder[i][j].setBackground(Color.DARK_GRAY);
Board.add(panelHolder[i][j]);
layeredpane.setLayer(panelHolder[i][j], JLayeredPane.DEFAULT_LAYER);
panelHolder[i][j].setVisible(false);
} // end 'j' for
} // end 'i' for
ArrayList<Block> initBlocks = initBoard.getBlocks();
//int count = 0; //DEBUG
for (Block block : initBlocks) {
this.drawBlock(block);
//count++;
//if(count > 4) { break; }
} // end 'for'
Board.setBackground(Color.DARK_GRAY);
Board.setVisible(true);
setVisible(true);
} // end 'run'
private void drawBlock(Block block) {
Dimension blockSize = new Dimension(block.getWidth()*100, block.getHeight()*100);
System.out.println(blockSize.width);
System.out.println(blockSize.height);
JPanel screenBlock = new JPanel();
screenBlock.setPreferredSize(blockSize);
screenBlock.setMinimumSize(blockSize);
screenBlock.setMaximumSize(blockSize);
screenBlock.setSize(blockSize);
screenBlock.setBackground(Color.BLUE);
screenBlock.setBorder(BorderFactory.createLineBorder(Color.BLACK));
layeredpane.setLayer(screenBlock, JLayeredPane.MODAL_LAYER);
int leftRow = block.getRow();
int leftCol = block.getColumn();
panelHolder[leftRow][leftCol].setSize(blockSize);
panelHolder[leftRow][leftCol].setVisible(true);
panelHolder[leftRow][leftCol].add(screenBlock);
layeredpane.setLayer(panelHolder[leftRow][leftCol], JLayeredPane.MODAL_LAYER);
screenBlock.setVisible(true);
}// end 'drawBlock'
public static void main(String[] args) {
String file = "C:\\Users\\Tim\\Desktop\\init.from.handout.txt";
String goal = "C:\\Users\\Tim\\Desktop\\goal.2.from.handout.txt";
/*
A SolverPuzzle object is the object which actually solves the algorithm -
when the class is constructed, it takes the file path of the inital
configuration as an input, as well as the file path of the goal
configuration. It has the following fields:
A 'board' object which specifies the inital configuration of the board.
It contains an ArrayList of Block objects(Remember block objects store
the height and width of the block, as well as the address of the
top left corner of block) which specify the starting
blocks, an ArrayList of EmptySpace objects which specify the empty
spaces on the board, an ArrayList of Move objects, which contain
the legal moves of the configuration, and the height and width of
the tray (in this application, the tray will always be 5 x 4).
An ArrayList of Block objects which specify the ending configuration.
A LinkedList of Move objects which specify the shortest possible
list of Moves which brings the configuration to a position which
satisfies the goal position. A Move object has three fields -
The block object being moved, and the row and column of the
top left corner of the block in the new position.
*/
SolverPuzzle test;
try { test = new SolverPuzzle(file, goal); }
catch (IOException ex) {
System.out.println("IOException");
return;
}
Board testBoard = test.getStartBoard();
ArrayList<Block> testGoalBlocks = test.getGoalBlocks();
LinkedList<Move> testMoveSolution = test.getMoveList();
// testing the gui
SolverPuzzleGUI testGUI = new SolverPuzzleGUI(testBoard, testGoalBlocks,
testMoveSolution);
testGUI.runSimulation();
}
} // end class 'SolverPuzzleGUI'
Here's the current output vs desired output.
http://imgur.com/a/ykXXP
So specifically, I have two questions:
1 - Why is the image only showing the top left corners of the blocks instead of the whole block?
2 - Is it better to continue using the GridLayout or switch to GridBagLayout?
Thanks

GridBagLayout would definitely be suitable for want you want to do. For example, you can expand components to envelop more than one column or row - just like what you want to do. Check out the java tutorials for how to use them.
A key point to remember when using GridBagLayoutis that you need to reset the Constraints after each component, assuming that they're unique to that particular component.
Also - I can't discern what you mean by only showing the top-left - it looks likes its showing the whole thing to me...

More Efficient Way of making multiple objects

I am trying to make a memory game with Java. The game is basically going to be some squares in a grid that is 4x4 at the moment just for testing purposes. I have created my Square class, and programmed what i want them to do in that class, and then created a square object in another Class that handles the "Normal Mode" of the game. Now since i have a 4x4 grid of squares I need to make 16 different Squares (Or at least that's what i'm thinking at the moment). I also need to draw the Squares in their corresponding place.
My Question: What is the most efficient way of creating 16 of these Square objects while still being able to manipulate them individually? (Sort of like each having their own name; Square, Square1, Square2, etc).
I am also using the Slick2D library.

As mentioned above, Square[][] squareGrid = new Square[4][4] is a good way to go about this;
then you can initialize all 16 of them using:
for (int i = 0; i < squareGrid.length; i++)
for(int j = 0; j < squareGrid[i].length; j++)
squareGrid[i][j] = new Square();
now each square automatically has its own unique (row, col) id.
for example,
squareGrid[1][2].callSomeFunctionInSquareClass();
can be used to manipulate the square at 2nd row, 3rd column.
This way you will avoid scanning through all the squares to get the one at a particular cell on the grid, thus making it much more efficient.
happy coding :)

You can try Square[][] grid = new Square[4][4]

I would use a Square[][] array, e.g. Square[][] squares = new Square[4][4], and then initialise it with all 16 Squares in two nested loops:
for (int x = 0; x < squares.length) x++)
for (int y = 0; y < squares[x].length; y++)
squares[x][y] = new Square(x, y);

How can I create actions for a variable number of buttons?

I'm creating a user interface for a game that I have to do as a class project, and needless to say I'm not experienced with Swing.
I did learn about actionevents and whatnot for simple button pushes, but in those cases I knew how many buttons would be on screen. Here, I need to create a board with an arbitrary number of tiles, which will be represented as buttons in Swing. I need to push a button and "move" my character from one tile to another, so I need to call a method on one tile object to remove the player from that tile, and then add it to another tile.
So my question is, given that the number of buttons is generated at runtime (and stored in a 2d array) how can I make an actionlistener that is able to distinguish between each unique button?

Set all your buttons to the same handler:
ActionListener a = new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
if (evt.getSource() == buttons[0][0]) {
}
// etc
// common handling
}
};
for (int i = 0; i < height; ++i)
for (int j = 0; j < width; ++j)
buttons[i][j].addActionListener(a);