Trouble passing context to helper class method

Question

Not entirely sure if I'm using those terms (context, helper class) correctly, so excuse me if I'm not.

Anyway, my issue is that I have a class chessboard which needs to call a method in another class, this being the class for the 'knight' piece. The method in this knight class generates a list of possible moves that the knight could make given its current position on the chessboard.

Once the 'possibleMoves' method (located in the knight class) is called, I want it to generate a Toast that will be displayed. However I'm having trouble filling the Toast with a context to use. I'm not sure how to pass the context of the chessboard to the knight class when it's called.

I hope that makes sense.

My code is below -

chessboard portion:

final ImageView s01 = (ImageView) findViewById(R.id.s01);
        s01.setClickable(true);
        s01.setOnClickListener(new OnClickListener() {
                public void onClick(View v) {
                    if (s01.getDrawable() != (null)) {
                        String Piece = s01.getTag().toString();

                        switch (Piece) {
                            case "black_knight":
                                knight blackKnight = new knight();
                                blackKnight.possibleMoves(0, 1);
                                break;

                        }

                        }


                    }
                });

knight class:

public class knight extends piece {
    static String chessBoard[][] = chessboard.chessBoard;
    //private static Context boardContext;
    @Override
    public String possibleMoves(int r, int c) {
        String list="", oldPieceRecord;

        for (int j=-1; j<=1; j+=2) {
            for (int k=-1; k<=1; k+=2) {
                try {
                    if (Character.isUpperCase(chessBoard[r+j][c+k*2].charAt(0)) || " ".equals(chessBoard[r+j][c+k*2])) {
                        oldPieceRecord=chessBoard[r+j][c+k*2];
                        chessBoard[r][c]=" ";
                        chessBoard[r+j][c+k*2]="k";
                        if (kingSafe()) {
                            list=list+r+c+(r+j)+(c+k*2)+oldPieceRecord+(oldPieceRecord.equals(" ") ? "": " ");
                        }
                        chessBoard[r][c]="k";
                        chessBoard[r+j][c+k*2]=oldPieceRecord;
                    }
                } catch (Exception e) {}
                try {
                    if (Character.isUpperCase(chessBoard[r+j*2][c+k].charAt(0)) || " ".equals(chessBoard[r+j*2][c+k])) {
                        oldPieceRecord=chessBoard[r+j*2][c+k];
                        chessBoard[r][c]=" ";
                        chessBoard[r+j*2][c+k]="k";
                        if (kingSafe()) {
                            list=list+r+c+(r+j*2)+(c+k)+oldPieceRecord;
                        }
                        chessBoard[r][c]="k";
                        chessBoard[r+j*2][c+k]=oldPieceRecord;
                    }
                } catch (Exception e) {}
            }
        }
        Toast.makeText( ,list, Toast.LENGTH_LONG).show();
        return list;
    }

I understand that some context indicator should go before the comma in the Toast.

Answer 1

You can require a Context object in the constructor:

private Context mContext;
public knight(Context context)
{
   mContext=context;
   super();
}
...
Toast.makeText(mContext ,list, Toast.LENGTH_LONG).show();

As was said in the comments by peace walker and codeMagic, you can instantiate this object like so:

In a Fragment:

knight blackKnight = new knight(getActivity());

In an Activity :

knight blackKnight = new knight(ChessboardActivity.this);

or

knight blackKnight = new knight(View.getContext());

Answer 2

Hope i can help you (i don't know english). You can create constructor of class knight like this.

 public class knight extends piece {
static String chessBoard[][] = chessboard.chessBoard;
private Context mContext;
public knight(Context mContext){
    this.mContext = mContext;       
}
// your code

}

and :

knight blackKnight = new knight(yourContext);

Now you can use context in your class.