GUI-国际象棋游戏将碎片拖放到板上“ 2D阵列”

Question

Hello I'm trying to make a chess game, so far I have created my pieces and I can move them with my mouse.

Now I'm trying to make the board with a 2D array that contains chess piece, so that I when I drag a piece on the board, it adds the piece in the array for example on the image

I drag the piece to (2,3) and board[2][3] = pawn

But I'm not sure how to implement it, I thought about using coordinates like when I drag it into the middle, say I have a frame size of 800x800 and board size of 8 so when I drag my piece to the coordinate (400,400) , board[4][4] = pawn , but then I have to do it for each cell and I'm gonna end up with up 64 if conditions, is there some kind of trick to do it or is my approach wrong?

If( piece's position is between ... and ... ){
then put into board[0][1]}

If ( piece's position is between ... ) {
then put then put into board[1][1]} 

Answer 1

You could use a mouseListener on the JLabels you have in your board! First, build your board by using 8*8 (chess is 8*8, right?) JLabels, store them in some array.

JLabel[][] boardFields = new JLabel[8][8];

You pack these in a JPanel which has GridBagLayout . You can lay them out in the desired pattern pretty easily by using the GridBagContraints class'v gridx and gridy variables.

Now what you do is make a static variable somewhere, lets call it selectedPiece . Lets add the mouse listeners to all of our field labels:

for(int i=0;i<8;i++){
   for(int j=0;j<8;j++){

      boardFields[i][j] = new JLabel();
      //set its background white or black here

      //each field will listen to a mouse press (means we selected this piece)
      //and a mouse release (meaning we placed the selected piece here)
      boardFields[i][j].addMouseListener(new MouseAdapter(){

           public void mousePressed(MouseEvent e){
                selectedPiece = //set piece on this field somehow
                //update the background to plain black or white
                //make the icon of the piece follow the cursor
           }

           public void mousePressed(MouseEvent e){
                //update the background to contain the selectedPiece
                //make the icon of the piece stop followin the cursor
                 selectedPiece = null //de-select the piece since we just placed it
           }
      )};
   }
}

This is just a sketch obviously, but it should give you the idea!