Question

I have here a code snippet of my Tetris project.

private class Game implements Runnable  {
    private int numDropped = -1;
    public void setCount(int count){
        count++;
    }
    public int getCount(){
        return count;
    }
    public void run() {
        int column = 4, style = Piece.SHAPES[(int) (Math.random() * 7)][(int) (Math.random() * 4)];
        while (onPlay) {
            if (piece != null) {
                if (piece.isAlive()) {
                    try {
                        Thread.currentThread().sleep(100);
                    } 
                    catch (InterruptedException ie) {
                        ie.printStackTrace();
                    }
                    continue;
                }
            }

            checkFullLine();  
            if (isGameOver()) {
                playItem.setEnabled(true);
                pauseItem.setEnabled(true);
                resumeItem.setEnabled(false);
                rightPanel.setPlayButtonEnable(true);
                rightPanel.setPauseButtonLabel(true);

                displayGameOver();
                return;
            }
            piece = new Piece(style, -1, column, board);
            piece.start();
            style = Piece.SHAPES[(int) (Math.random() * 7)][(int) (Math.random() * 4)];
            rightPanel.setTipStyle(style);
            numDropped = numDropped+1;
            RightPanel.scoreTextField.setText(numDropped+"");
        }
    }
}

The class Game is an inner class, by the way. Whenever a new piece goes down, the value of numDropped increments (as displayed in a JTextField) but then after a short while goes back to zero. Did I misplace the

numDropped = numDropped+1;
RightPanel.scoreTextField.setText(numDropped+"");

? Or because of something else like being static and stuff. Please help me. I’m kinda new in Java. Thank you very much!

Answer 1

The code you have posted will definitely never update the scoreTextField to a value that is smaller than the value it used earlier.

The first thing I would suspect is that there is some other code that updates scoreTextField to a value that is not equal to numDropped.

Update

In your additionally posted code I see this:

RightPanel.scoreTextField = new JTextField(numDropped+"");

This is wrong; delete it and uncomment the line above, that sets the text on the existing text field.

Moreover, you’ve got this code:

timer = new Timer(
                500, new ActionListener() {
                    public void actionPerformed(ActionEvent ae) {
                        scoreTextField.setText("" + game.getScore());
                        int scoreForLevelUpdate = game.getScoreForLevelUpdate();
                        if (scoreForLevelUpdate >= Tetris.PER_LEVEL_SCORE && scoreForLevelUpdate > 0)
                            game.levelUpdate();
                    }
                }
        );

        timer.start();

Clearly this will overwrite your scoreTextField with the game score, whereas in the Game‘s loop you are writing the number of dropped elements. Judging from the name of your variable scoreTextField, you should change the code in Game to update some other text field and not the one used to display score.

Yet another thing that is wrong in your design is this:

Thread thread = new Thread(new Game());
thread.start();

You are starting another thread to control the gameplay. You must not update any Swing components outside the main GUI thread, the so-called Event Dispatch Thread (EDT). My suggestion is to redesign your code similar to what you have done above with your timer variable: don’t start another thread; instead schedule another Timer with the interval of 100 milliseconds, and implement the associated actionPerformed based on your current code in while (onPlay) — all you’ll need to change is that you don’t need the loop anymore. Of course, Thread.sleep(100) will also be redundant. When the game is over, just cancel your timer task.

Not directly related to the problem of this question, but this code

public void setCount(int count){
    count++;
}

is also wrong: it doesn’t write to the instance variable count, but just increments the supplied argument, immediately discarding it (it’s just a local variable).