尝试在if语句中暂停程序执行（Swing）

Question

I'm trying to pause my program and have been looking at using Thread.Sleep(). After reading about the problems this causes I am trying to implement a Swing Timer. However, it seems that Swing timers fire ActionEvents... I'm only looking to pause program execution and have a JLabel change between the following

mPlayerLastRollLabel.setText("Player rolled: ...");

//PAUSE

mPlayerLastRollLabel.setText("Player rolled: " + mFaceNumber);

How would I use a Timer in the case below to pause the program where I've marked it:

class ClickListener implements ActionListener {
        public void actionPerformed(ActionEvent event) {
            if (mPlayerTurn && event.getSource() == playerRollButton) {
                mFaceNumber = rollDie();
                mPlayerLastRollLabel.setText("Player rolled: ...");

                **// want to pause here //**

                mPlayerLastRollLabel.setText("Player rolled: " + mFaceNumber);

                if (mFaceNumber != 1) {
                    mSubTotal += mFaceNumber;
                    mPlayerSubtotalLabel.setText("Player's current subtotal: " + mSubTotal);
                }
                else {
                    mSubTotal = 0;
                    mPlayerSubtotalLabel.setText("Player's current subtotal: " + mSubTotal);
                    mPlayerTurn = false;
                    mComputerTurn = true;
                }
            }

            if (mPlayerTurn && event.getSource() == playerEndTurnButton) {
                mPlayerTotalScore += mSubTotal;
                mPlayerCurrentTotalScoreLabel.setText("Player's current total score: " + mPlayerTotalScore);
                mSubTotal = 0;
                System.out.println(mPlayerTotalScore);
                mPlayerTurn = false;
                mComputerTurn = true;
            }

            if (mComputerTurn && event.getSource() == computerRollButton) {
                mFaceNumber = rollDie();

                mComputerLastRollLabel.setText("Computer rolled: " + mFaceNumber);

                if (mFaceNumber != 1)
                    mSubTotal += mFaceNumber;
                else {
                    mSubTotal = 0;
                    mPlayerTurn = true;
                    mComputerTurn = false;
                }
            }

            if (mComputerTurn && event.getSource() == computerEndTurnButton) {
                mComputerTotalScore += mSubTotal;
                mSubTotal = 0;
                System.out.println(mComputerTotalScore);
                mPlayerTurn = true;
                mComputerTurn = false;
            }


        }
    }

Answer 1

That is because swing timer is asynchronous. So you have to put second line of your code (and all following logic) into action listener like:

mPlayerLastRollLabel.setText("Player rolled: ...");
Timer t = new Timer(5000, new ActionListener(){
    public void actionPerformed(ActionEvent ae){
        mPlayerLastRollLabel.setText("Player rolled: " + mFaceNumber);
    }
});
t.setRepeats(false);
t.start();

Or you can put second half after sleep into separate function and call it from actionPerfomed method. Doing it this way instead of Thread.sleep you release graphical thread (which is one for all UI) until your sleeping time is up. If don't release graphical thread then your UI would freeze because there would be no thread to react to user actions.